giovanivaldrighi/sciq_filtered · Datasets at Hugging Face

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Compounds that are capable of accepting electrons, such as o 2 or f2, are called what?	residues	antioxidants	Oxygen	oxidants	Oxidants and Reductants Compounds that are capable of accepting electrons, such as O 2 or F2, are calledoxidants (or oxidizing agents) because they can oxidize other compounds. In the process of accepting electrons, an oxidant is reduced. Compounds that are capable of donating electrons, such as sodium metal or cyclohexane (C6H12), are calledreductants (or reducing agents) because they can cause the reduction of another compound. In the process of donating electrons, a reductant is oxidized. These relationships are summarized in Equation 3.30: Equation 3.30 Saylor URL: http://www. saylor. org/books.
What term in biotechnology means a genetically exact copy of an organism?	phenotype	adult	male	clone	But transgenic animals just have one novel gene. What about an animal with a whole new genome? Could a clone , a genetically exact copy of an organism, be developed using techniques associated with biotechnology? It could be argued that human cloning is one of the inevitable outcomes of modern biotechnology. It "simply" involves the removal of the nucleus from a somatic cell and its placement into an unfertilized egg cell whose nucleus has either been deactivated or removed. This new cell would mimic the zygote, the first diploid cell of a new organism. This new zygote is allowed to become established, and a few days later is placed into the uterus of a surrogate mother. Theoretically this would result in an individual genetically identical to the donor. Obviously, there are many ethical and legal issues associated with human cloning, and of course, it is not a "simple" procedure. But animal cloning is arguably a different story.
What is the height above or below sea level called?	variation	depth	latitude	elevation	As you know, the surface of Earth is not flat. Some places are high, and some places are low. For example, mountain ranges like the Sierra Nevada in California or the Andes in South America are high above the surrounding areas. An accurate location must take into account the third dimension. Elevation is the height above or below sea level. Sea level refers to the height of the ocean’s surface. This is the midpoint between high and low tide. Sea level can vary from place to place, but scientists base their elevation measurements on the average, or mean, sea level to make sure they have a standard reference point.
The bird ancestor that lived in trees developed what feature commonly associated with birds?	beaks	tails	webbed feet	wings	Wings evolved in a bird ancestor that lived in trees. Thus, wings are modified arms that helped the animal glide from branch to branch.
What term means the amount of water vapor in the air?	ambient	temperature	pressure	humidity	Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation.
Paracrine signals move by what method through the extracellular matrix?	transfusion	osmosis	deposition	diffusion	Paracrine Signaling Signals that act locally between cells that are close together are called paracrine signals. Paracrine signals move by diffusion through the extracellular matrix. These types of signals usually elicit quick responses that last only a short amount of time. In order to keep the response localized, paracrine ligand molecules are normally quickly degraded by enzymes or removed by neighboring cells. Removing the signals will reestablish the concentration gradient for the signal, allowing them to quickly diffuse through the intracellular space if released again. One example of paracrine signaling is the transfer of signals across synapses between nerve cells. A nerve cell consists of a cell body, several short, branched extensions called dendrites that receive stimuli, and a long extension called an axon, which transmits signals to other nerve cells or muscle cells. The junction between nerve cells where signal transmission occurs is called a synapse. A synaptic signal is a chemical signal that travels between nerve cells. Signals within the nerve cells are propagated by fast-moving electrical impulses. When these impulses reach the end of the axon, the signal continues on to a dendrite of the next cell by the release of chemical ligands called neurotransmitters by the presynaptic cell (the cell emitting the signal). The neurotransmitters are transported across the very small distances between nerve cells, which are called chemical synapses (Figure 9.3). The small distance between nerve cells allows the signal to travel quickly; this enables an immediate response, such as, Take your hand off the stove! When the neurotransmitter binds the receptor on the surface of the postsynaptic cell, the electrochemical potential of the target cell changes, and the next electrical impulse is launched. The neurotransmitters that are released into the chemical synapse are degraded quickly or get reabsorbed by the presynaptic cell so that the recipient nerve cell can recover quickly and be prepared to respond rapidly to the next synaptic signal.
Presence of a cell wall, large central vacuole, and organelles called plastids distinguish what type of cell?	heterotroph	animal	reproductive	plant	All but one of the structures described above are found in plant cells as well as animal cells. The only exception is centrioles, which are not found in plant cells. Plant cells have three additional structures that are not found in animals cells. These include a cell wall, large central vacuole, and organelles called plastids. You can see these structures in the model of a plant cell in Figure below . You can also see them in the interactive plant cell at this link:.
Digestion of proteins begins with acids in what organ?	brain	colon	liver	stomach	24.4 Protein Metabolism Digestion of proteins begins in the stomach, where HCl and pepsin begin the process of breaking down proteins into their constituent amino acids. As the chyme enters the small intestine, it mixes with bicarbonate and digestive enzymes. The bicarbonate neutralizes the acidic HCl, and the digestive enzymes break down the proteins into smaller peptides and amino acids. Digestive hormones secretin and CCK are released from the small intestine to aid in digestive processes, and digestive proenzymes are released from the pancreas (trypsinogen and chymotrypsinogen). Enterokinase, an enzyme located in the wall of the small intestine, activates trypsin, which in turn activates chymotrypsin. These enzymes liberate the individual amino acids that are then transported via sodium-amino acid transporters across the intestinal wall into the cell. The amino acids are then transported into the bloodstream for dispersal to the liver and cells throughout the body to be used to create new proteins. When in excess, the amino acids are processed and stored as glucose or ketones. The nitrogen waste that is liberated in this process is converted to urea in the urea acid cycle and eliminated in the urine. In times of starvation, amino acids can be used as an energy source and processed through the Krebs cycle.
Many species of rotifers exhibit haplodiploidy, which is a method of what?	respiration	circulation	digestion	gender determination	Watch this video (http://openstaxcollege. org/l/rotifers) to see rotifers feeding. Rotifers are pseudocoelomates commonly found in fresh water and some salt water environments throughout the world. Figure 28.17 shows the anatomy of a rotifer belonging to class Bdelloidea. About 2,200 species of rotifers have been identified. Rotifers are dioecious organisms (having either male or female genitalia) and exhibit sexual dimorphism (males and females have different forms). Many species are parthenogenic and exhibit haplodiploidy, a method of gender determination in which a fertilized egg develops into a female and an unfertilized egg develops into a male. In many dioecious species, males are short-lived and smaller with no digestive system and a single testis. Females can produce eggs that are capable of dormancy for protection during harsh environmental conditions.
What is the most abundant metal of the earth's crust?	magnetite	calcium	copper	aluminum	Metals represent approximately 25% of the elemental makeup of the Earth's crust. The bulk of these metals, primarily aluminum, iron, calcium, sodium, potassium, and magnesium, are typically found in combined form. The most abundant metal is aluminum, which occurs almost exclusively as the ionic mineral bauxite. The other most common metals, including iron, sodium, potassium, magnesium, and calcium, are also found primarily as the cationic portion of an ionic compound. Very few metals actually occur naturally as pure substances. The ones that do are often referred to as precious or semi-precious metals.
What is the term for the total kinetic energy of moving particles of matter?	Newton's energy	heavy energy	mechanical energy	thermal energy	The total kinetic energy of moving particles of matter is called thermal energy.
Chemical reactions involve a transfer of heat energy. measured in what?	thermals	amps	amperes	joules	Chemical reactions involve a transfer of heat energy. Measured in joules.
Most fungi get organic compounds from what?	carnivorous organisms	inorganic material	living organisms	dead organisms	Most fungi get organic compounds from dead organisms. They are decomposers called saprotrophs. A saprotroph feeds on any remaining organic matter after other decomposers do their work. Fungi use enzymes to digest organic remains and then absorb the resulting organic compounds. As decomposers, fungi are vital for the health of ecosystems. They break down nonliving organic matter and release the nutrients into the soil. Plants can then use the nutrients and pass them on to herbivores and other consumers.
Pairs of nitrogenous bases are attached to each other by?	magnetism	potassium bonds	ionic bonds	hydrogen bonds
The strength of a base depends on the concentration of _______ it produces when dissolved in water?	monoxide ions	combustion ions	calcium ions	hydroxide ions	The strength of a base depends on the concentration of hydroxide ions it produces when dissolved in water. For example, sodium hydroxide completely breaks down into ions in water, so it is a strong base. However, only a fraction of ammonia breaks down into ions, so it is a weak base.
Organisms that live deep in the ocean must be able to withstand what?	tsunamis	the sun	significant water pressure	extreme water pressure	Organisms that live deep in the ocean must be able to withstand extreme water pressure, very cold water, and complete darkness. However, even here, thriving communities of living things can be found. Organisms cluster around hydrothermal vents in the ocean floor. The vents release hot water containing chemicals that would be toxic to most other living things. The producers among them are single-celled chemoautotrophs. They make food using energy stored in the chemicals. The tube worms in this chapter's opening photo depend on these chemoautotrophs for food.
What instrument is used to make very sensitive mass measurements in a laboratory, usually in grams?	scale	speedometer	thermometer	analytical balance	An analytical balance makes very sensitive mass measurements in a laboratory, usually in grams.
The lens focuses light on the retina , which covers the back of the inside of the eye. the retina has light-sensing photoreceptor cells called?	tubes and rods	cones and tubes	holes and cones	rods and cones	The lens focuses light on the retina , which covers the back of the inside of the eye. The retina has light-sensing photoreceptor cells called rods and cones. Rods let us see in dim light. Cones let us detect light of different colors.
Temperature, water, soil, and air are examples of nonliving factors of an ecosystem, also termed what?	diverse factors	nucleic factors	conditional factors	abiotic factors	Ecology is the study of ecosystems. That is, ecology is the study of how living organisms interact with each other and with the nonliving part of their environment. An ecosystem consists of all the nonliving factors and living organisms interacting in the same habitat . Recall that living organisms are biotic factors . The biotic factors of an ecosystem include all the populations in a habitat, such as all the species of plants, animals, and fungi, as well as all the micro-organisms. Also recall that the nonliving factors are called abiotic factors . Abiotic factors include temperature, water, soil, and air.
Which kind of muscle regulates air flow in lungs?	alveoli	vascular	striated	smooth	Smooth muscle regulates air flow in lungs.
What type of bonds are formed by the side-to-side overlap of p orbitals?	theta bonds	sigma bonds	omega bonds	pi bonds	Sigma bonds are formed by the end-to-end overlap of bonding orbitals. Pi bonds are formed by the side-to-side overlap of p orbitals. Single bonds are normally sigma bonds. A double or triple bond consists of one sigma bond and either one or two pi bonds.
What is another name for the vertebral column?	brain stem	nerve column	pillar	backbone	animal in Phylum Chordata that has a vertebral column, or backbone.
The temperature at which a substance melts is called its what point?	freezing	boiling	change	melting	The temperature at which a substance melts is called its melting point. Melting point is a physical property of matter. The gold pictured in the Figure above , for example, has a melting point of 1064°C. This is a high melting point, and most other metals also have high melting points. The melting point of ice, in comparison, is much lower at 0°C. Many substances have even lower melting points. For example, the melting point of oxygen is -222°C.
Humans are among the most versatile of mammals with what type of diet?	vegetarian	carnivore	herbivore	omnivore
Solute potential is also called osmotic potential because solutes affect the direction of what?	electrolysis	permeability	electrolysis	osmosis
Fungi, such as black bread mold (rhizopus nigricans), have haploid-dominant what?	mutations	birth cycles	gene pools	life cycles	Figure 11.9 Fungi, such as black bread mold (Rhizopus nigricans), have haploid-dominant life cycles. The haploid multicellular stage produces specialized haploid cells by mitosis that fuse to form a diploid zygote. The zygote undergoes meiosis to produce haploid spores. Each spore gives rise to a multicellular haploid organism by mitosis. (credit “zygomycota” micrograph: modification of work by “Fanaberka”/Wikimedia Commons).
The electrode at which oxidation occurs is called?	calomel	diode	cathode	the anode	The electrode at which oxidation occurs is called the anode . The zinc anode gradually diminishes as the cell operates due to the loss of zinc metal. The zinc ion concentration in the half-cell increases. Because of the production of electrons at the anode, it is labeled as the negative electrode.
The lens and other parts of the eye work together to focus a real image on what eye structure?	cornea	iris	pupil	retina	As just described, the eyes collect and focus visible light. The lens and other structures of the eye work together to focus a real image on the retina. The image is upside-down and reduced in size, as you can see in Figure below . The image reaches the brain as electrical signals that travel through the optic nerve. The brain interprets the signals as shape, color, and brightness. It also interprets the image as though it were right-side up. The brain does this automatically, so what we see is always right-side up. The brain also “tells” us what we are seeing.
What is required to move or change matter from one state to another?	evolution	food	gravity	energy	Energy provides the ability to move or change matter from one state to another (for example, from solid to liquid). Every living thing needs energy to live and grow. Your body gets its energy from food, but that is only a small part of the energy you use every day. Cooking your food takes energy, and so does keeping it cold in the refrigerator or the freezer. The same is true for heating or cooling your home. Whether you are turning on a light in the kitchen or riding in a car to school, you are using energy. Billions of people all around the world use energy, so there is a huge demand for resources to provide all of this energy. Why do we need so much energy? The main reason is that almost everything that happens on Earth involves energy.
What contains positive protons and neutral neutrons?	epidermis	electrons	ions	nucleus	The nucleus is at the center of the atom. It contains positive protons and neutral neutrons. Negative electrons constantly move about the nucleus.
Natural gas is the predominately made up of?	sulfur	hydrogen	carbon	methane	Natural gas is mostly methane. Natural gas is usually found with petroleum. People prefer to burn natural gas when possible because it is relatively clean.
Which organs control the amount of water, ions, and other substances in the blood by excreting more or less of them in urine?	ears	lungs	tongue	kidneys	The kidneys play many vital roles in homeostasis. They filter all the blood in the body many times each day and produce a total of about 1.5 liters of urine. The kidneys control the amount of water, ions, and other substances in the blood by excreting more or less of them in urine. The kidneys also secrete hormones that help maintain homeostasis. Erythropoietin, for example, is a kidney hormone that stimulates bone marrow to produce red blood cells when more are needed. The kidneys themselves are also regulated by hormones. For example, antidiuretic hormone from the hypothalamus stimulates the kidneys to produce more concentrated urine when the body is low on water.
What is a therian mammal in which the embryo is born at an early, immature stage?	carnivore	rodent	bat	a marsupial	Marsupials have a different way of reproducing that reduces the mother’s risks. A marsupial is a therian mammal in which the embryo is born at an early, immature stage. The embryo completes its development outside the mother’s body in a pouch on her belly. Only a minority of therian mammals are marsupials. They live mainly in Australia. Examples of marsupials are pictured in Figure below .
What are fungi which feed on living cells called?	symbiotic	static	predatory	parasitic	23.24 Nutrition Fungi are saprophytes. When they find a source of food (e. dead wood, orange peel) , they decompose it and digest it. The enzymes break down larger organic molecules in the substrate into smaller molecules. These smaller molecules diffuse into the fungus, where they are used to allow growth and repair. Fungi which feed on living cells are parasitic. For example, athlete's foot grows on the human foot. These kinds of fungi produce hyphae called haustoria, which can penetrate host cells without immediately killing them. However, they are friendlier species of fungi. Many fungi live symbiotically with plants or animals. For example, most trees have fungi living in close contact with their roots. In this relationship, known as a mycorrhiza, there are many benefits: • Growing around the plant roots and often entering plant cells, the hyphae absorb minerals from the soil and release them in the roots. The fungi gets its source of food (organic nutrients) while delivering food to the plant. • The mycelium here would increase the surface area, thus the absorptive surface, of the plant roots. • The fungal cells help to maintain air and water flow in the soil around the roots. • The fungi may prevent other potentially pathogenic fungi to attack the tree.
What is the diffusion of water through a semipermeable membrane down its concentration gradient	Permable	nutrients	mirrors	osmosis	Figure 3.7 Osmosis Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration). In the beaker on the left, the solution on the right side of the membrane is hypertonic.
In phyisics, what is considered to be the rotational version of force?	pressure	work	energy	torque	Torque is equal to the cross product as stated above. In general, one can simplify by saying that the torque is equal to the force acting on the object multiplied by the perpendicular distance from the application of the force to the rotational axis. Say you had a seesaw. It is easier to exert torque, get the seesaw to move, if you pushed on the board near the end rather than near the middle. It is the rotational version of Force.
Skeletal muscles are attached to the skeleton by tough connective tissues called what?	cords	fibers	veins	tendons	Skeletal muscles are attached to the skeleton by tough connective tissues called tendons (see Figure above ). Many skeletal muscles are attached to the ends of bones that meet at a joint . The muscles span the joint and connect the bones. When the muscles contract, they pull on the bones, causing them to move.
What is the ability to see called?	hearing	thought	smell	vision	The ability to see is called vision . This ability depends on more than healthy eyes. It also depends on certain parts of the brain, because the brain and eyes work together to allow us to see. The eyes collect and focus visible light. The lens and other structures of the eye work together to focus an image on the retina. The image is upside-down and reduced in size, as you can see in the Figure below . Cells in the retina change the image to electrical signals that travel to the brain through the optic nerve. The brain interprets the electrical signals as shape, color, and brightness. It also interprets the image as though it were right-side up. The brain does this automatically, so what we see always appears right-side up. The brain also interprets what we are seeing.
Which two major innovations allowed seed plants to reproduce in the absence of water?	salt and pollen	bee and pollen	root and pollen	seed and pollen	CHAPTER SUMMARY 26.1 Evolution of Seed Plants Seed plants appeared about one million years ago, during the Carboniferous period. Two major innovations—seed and pollen—allowed seed plants to reproduce in the absence of water. The gametophytes of seed plants shrank, while the sporophytes became prominent structures and the diploid stage became the longest phase of the lifecycle. Gymnosperms became the dominant group during the Triassic. In these, pollen grains and seeds protect against desiccation. The seed, unlike a spore, is a diploid embryo surrounded by storage tissue and protective layers. It is equipped to delay germination until growth conditions are optimal. Angiosperms bear both flowers and fruit. The structures protect the gametes and the embryo during its development. Angiosperms appeared during the Mesozoic era and have become the dominant plant life in terrestrial habitats.
Water can be broken down into hydrogen and oxygen gases by the addition of what?	demand	motion	mineral	energy	Chemistry in Everyday Life Decomposition of Water / Production of Hydrogen Water consists of the elements hydrogen and oxygen combined in a 2 to 1 ratio. Water can be broken down into hydrogen and oxygen gases by the addition of energy. One way to do this is with a battery or power supply, as shown in (Figure 1.15).
In humans, the only haploid cells are what reproductive cells?	uteral and sperm	dna and egg	sperm and dna	sperm and egg	The life cycle of a plant is very different from the life cycle of an animal. Humans are made entirely of diploid cells (cells with two sets of chromosomes, referred to as ''2n''). Our only cells that are haploid cells (cells with one set of chromosomes, ''n'') are sperm and egg cells. Plants, however, can live when they are are at the stage of having haploid cells or diploid cells. If a plant has a haploid chromosome number of 20, what is the diploid chromosome number? If the diploid chromosome number is 20, what is the haploid number?.
The lithosphere is divided into a dozen major and several minor what?	faults	zones	crystals	plates	The lithosphere is divided into a dozen major and several minor plates. Each plate is named for the continent or ocean basin it contains. Some plates are made of all oceanic lithosphere. A few are all continental lithosphere. But most plates are made of a combination of both.
What are used to indicate the number of atoms of an element that are in the compound?	digits	indices	suffixes	prefixes	Prefixes are used to indicate the number of atoms of an element that are in the compound.
Area, volume, and speed are all examples of what type of units?	known units	fundamental units	calculated measure	derived units	Derived units can be expressed as some combination of base units. Examples of derived units are area, volume, and speed.
Anything moving has what type of energy?	thermal	magnetic	potential	kinetic	Why do the air and sand of Death Valley feel so hot? It’s because their particles are moving very rapidly. Anything that is moving has kinetic energy, and the faster it is moving, the more kinetic energy it has. The total kinetic energy of moving particles of matter is called thermal energy . It’s not just hot things such as the air and sand of Death Valley that have thermal energy. All matter has thermal energy, even matter that feels cold. That’s because the particles of all matter are in constant motion and have kinetic energy.
A skydiver will reach what when the air drag equals their weight?	ending velocity	constant velocity	building velocity	terminal velocity	viscosity. Using the equation of the previous problem, find the viscosity of motor oil in which a steel ball of radius 0.8 mm falls with a terminal speed of 4.32 cm/s. The densities of the ball and the oil are 7.86 and 0.88 g/mL, respectively. A skydiver will reach a terminal velocity when the air drag equals their weight. For a skydiver with high speed and a large body, turbulence is a factor. The drag force then is approximately proportional to the square of the velocity. Taking the drag force to be F D = 1 ρAv 2 and setting this 2 equal to the person’s weight, find the terminal speed for a person falling “spread eagle. ” Find both a formula and a number for v t , with assumptions as to size. A layer of oil 1.50 mm thick is placed between two microscope slides. Researchers find that a force of 5.50×10 −4 N is required to glide one over the other at a speed of 1.00 cm/s when their contact area is 6.00 cm 2 . What is the oil’s viscosity? What type of oil might it be? 42. (a) Verify that a 19.0% decrease in laminar flow through a tube is caused by a 5.00% decrease in radius, assuming that all other factors remain constant, as stated in the text. (b) What increase in flow is obtained from a 5.00% increase in radius, again assuming all other factors remain constant? 43. Example 12.8 dealt with the flow of saline solution in an IV system. (a) Verify that a pressure of 1.62×10 4 N/m 2 is created at a depth of 1.61 m in a saline solution, assuming its density to be that of sea water. (b) Calculate the new flow rate if the height of the saline solution is decreased to 1.50 m. (c) At what height would the direction of flow be reversed? (This reversal can be a problem when patients stand up. ) 44. When physicians diagnose arterial blockages, they quote the reduction in flow rate. If the flow rate in an artery has been reduced to 10.0% of its normal value by a blood clot and the.
What is the adaptation that certain animals use to become less visible to predators and prey?	insulation	skeletons	speed	camouflage	Camouflage by the dead leaf mantis makes it less visible to both its predators and prey. If alarmed, it lies motionless on the rainforest floor of Madagascar, Africa, camouflaged among the actual dead leaves. It eats other animals up to the size of small lizards.
What is another term for blood clotting?	differentiation	adulation	oxidation	coagulation	Positive Feedback Loop A positive feedback loop maintains the direction of the stimulus, possibly accelerating it. Few examples of positive feedback loops exist in animal bodies, but one is found in the cascade of chemical reactions that result in blood clotting, or coagulation. As one clotting factor is activated, it activates the next factor in sequence until a fibrin clot is achieved. The direction is maintained, not changed, so this is positive feedback. Another example of positive feedback is uterine contractions during childbirth, as illustrated in Figure 33.21. The hormone oxytocin, made by the endocrine system, stimulates the contraction of the uterus. This produces pain sensed by the nervous system. Instead of lowering the oxytocin and causing the pain to subside, more oxytocin is produced until the contractions are powerful enough to produce childbirth.
What do you call the study of how organisms interact with their environment and each other?	climatology	biology	biochemistry	ecology	Most biological sciences are specialized areas of study. Biology includes biochemistry, cell biology, microbiology, immunology, genetics, physiology, zoology, ecology, evolutionary biology, and botany. Biochemistry is the study of the chemicals that make up life. Cell biology is the study of life at the level of the cell. Microbiology is the study of microscopic organisms. Immunology is the study of an organism's resistance to disease. Genetics is the study of how organisms pass traits to their offspring. The study of how the human body works is called physiology. Zoology is the study of animals. The study of how organisms interact with their environment and each other is called ecology. Evolutionary biology is the study of how populations and species change over time. Botany is the study of plants. The four unifying principles are important foundations for each and every field of biology. Applied fields of biology such as medicine and genetic research involve many specialized areas of study.
What phenomenon, which is most important in small populations, occurs because the alleles in an offspring generation are a random sample of the alleles in the parent generation?	genetic code	genetic DNA	genetic mutation	genetic drift	Genetic Drift Another way a population’s allele frequencies can change is genetic drift (Figure 11.7), which is simply the effect of chance. Genetic drift is most important in small populations. Drift would be completely absent in a population with infinite individuals, but, of course, no population is this large. Genetic drift occurs because the alleles in an offspring generation are a random sample of the alleles in the parent generation. Alleles may or may not make it into the next generation due to chance events including mortality of an individual, events affecting finding a mate, and even the events affecting which gametes end up in fertilizations. If one individual in a population of ten individuals happens to die before it leaves any offspring to the next generation, all of its genes—a tenth of the population’s gene pool—will be suddenly lost. In a population of 100, that 1 individual represents only 1 percent of the overall gene pool; therefore, it has much less impact on the population’s genetic structure and is unlikely to remove all copies of even a relatively rare allele. Imagine a population of ten individuals, half with allele A and half with allele a (the individuals are haploid). In a stable population, the next generation will also have ten individuals. Choose that generation randomly by flipping a coin ten times and let heads be A and tails be a. It is unlikely that the next generation will have exactly half of each allele. There might be six of one and four of the other, or some different set of frequencies. Thus, the allele frequencies have changed and evolution has occurred. A coin will no longer work to choose the next generation (because the odds are no longer one half for each allele). The frequency in each generation will drift up and down on what is known as a random walk until at one point either all A or all a are chosen and that allele is fixed from that point on. This could take a very long time for a large population. This simplification is not very biological, but it can be shown that real populations behave this way. The effect of drift on frequencies is greater the smaller a population is. Its effect is also greater on an allele with a frequency far from one half. Drift will influence every allele, even those that are being naturally selected.
What is the term for when an embryo fixes itself to the side of the uterus?	exploration	bacterial	parasite	implantation	Implantation occurs when the developing embryo fixes itself to the side of the uterus.
When exposed to ultraviolet, some substances, such as minerals, glow in characteristic visible wavelengths, a process called this?	pigment	plasma	chemical reaction	fluorescence	When exposed to ultraviolet, some substances, such as minerals, glow in characteristic visible wavelengths, a process called fluorescence. So-called black lights emit ultraviolet to cause posters and clothing to fluoresce in the visible. Ultraviolet is also used in special microscopes to detect details smaller than those observable with longer-wavelength visible-light microscopes. Things Great and Small: A Submicroscopic View of X-Ray Production X-rays can be created in a high-voltage discharge. They are emitted in the material struck by electrons in the discharge current. There are two mechanisms by which the electrons create X-rays. The first method is illustrated in Figure 24.18. An electron is accelerated in an evacuated tube by a high positive voltage. The electron strikes a metal plate (e. , copper) and produces X-rays. Since this is a high-voltage discharge, the electron gains sufficient energy to ionize the atom.
What disease occurs when the cell cycle is no longer regulated?	malnutrition	allergy	schizophrenia	cancer	Cancer is a disease that occurs when the cell cycle is no longer regulated. Cancer cells grow rapidly and may form a mass of abnormal cells called a tumor.
What are the little sacs at the end of the bronchioles called?	ganglion	lung	respiratory sacs	alveoli	The bronchioles lead to the alveoli. Alveoli are the little sacs at the end of the bronchioles ( Figure below ). They look like little bunches of grapes. Oxygen is exchanged for carbon dioxide in the alveoli. That means oxygen enters the blood, and carbon dioxide moves out of the blood. The gases are exchanged between the blood and alveoli by simple diffusion.
Circulating the air prevents ethylene from accumulating, and carbon dioxide inhibits synthesis of new what?	cellulose	alcohol	sulfur	ethylene
What is a fiber that is found only in mammals?	feathers	muscle	muscle	hair	Hair is a fiber that is found only in mammals. Its main component is keratin. A hair shaft consists of dead, keratin-filled cells that overlap each other like the shingles on a roof (see Figure below ). Like roof shingles, the overlapping cells help shed water from the hair.
What type of plants does human welfare depend greatly on?	fertilizer plants	mosses	ferns	seed plants	30.4 Human welfare depends greatly on seed plants.
What are cells without a nucleus called?	crustal cells	Monocyte Cells	heterogeneous cells	prokaryotic cells	Prokaryotic cells are cells without a nucleus. They are found in single-celled organisms. Eukaryotic cells are cells with a nucleus and other organelles. They are found mainly in multicellular organisms.
The hypothalamus is actually part of the brain, but it also secretes what?	electrolytes	enzymes	acids	hormones	The hypothalamus is actually part of the brain, but it also secretes hormones. Some of its hormones go directly to the pituitary gland in the endocrine system. These hypothalamus hormones tell the pituitary to either secrete or stop secreting its hormones. In this way, the hypothalamus provides a link between the nervous and endocrine systems.
What disease characterized by the extreme swelling of the limbs is caused by infection with a type of roundworm?	fibrosis	pulmonary edema	gigantism	elephantiasis	Roundworms can be free-living organisms, but they are probably best known for their role as significant plant and animal parasites. Most Nematodes are parasitic, with over 16,000 parasitic species described. Heartworms, which cause serious disease in dogs while living in the heart and blood vessels, are a type of roundworm. Roundworms can also cause disease in humans. Elephantiasis, a disease characterized by the extreme swelling of the limbs ( Figure below ), is caused by infection with a type of roundworm.
What is the study of water movement, including waves and ocean currents?	thermal oceanography	theoretical oceanography	experimental oceanography	physical oceanography	There are many branches of oceanography. Physical oceanography is the study of water movement, like waves and ocean currents. Physical oceanographers ask when or if a tsunami will hit a shoreline. Marine geologists look at rocks and structures in the ocean basins. These scientists ask how new ocean crust forms. Chemical oceanographers study the natural elements in ocean water. Chemical oceanographers might be concerned with where carbon dioxide goes in the oceans. Marine biologists look at marine life. There are lots of questions to ask about marine life!.
There are many types of asexual spores. conidiospores are unicellular or multicellular spores that are released directly from the tip or side of this?	goychay	ganglion	idioma	hypha	There are many types of asexual spores. Conidiospores are unicellular or multicellular spores that are released directly from the tip or side of the hypha. Other asexual spores originate in the fragmentation of a hypha to form single cells that are released as spores; some of these have a thick wall surrounding the fragment. Yet others bud off the vegetative parent cell. Sporangiospores are produced in a sporangium (Figure 24.9).
What are the hormones that cause a plant to grow?	pistills	sporozoans	pores	gibberellins	Gibberellins are hormones that cause the plant to grow. When gibberellins are applied to plants by scientists, the stems grow longer. Some gardeners or horticulture scientists add gibberellins to increase the growth of plants. Dwarf plants (small plants), on the other hand, have low levels of gibberellins ( Figure below ). Another function of gibberellins is to stop dormancy (resting time) of seeds and buds. Gibberellins signal that it’s time for a seed to germinate (sprout) or for a bud to open.
What are the smallest structural and functional unit of all living organisms?	proteins	neutrons	lipids	cells	If you zoom in very close on a leaf of a plant, or on the skin on your hand, or a drop of blood, you will find cells, you will find cells ( Figure below ). Cells are the smallest structural and functional unit of all living organisms. Most cells are so small that they are usually visible only through a microscope. Some organisms, like bacteria, plankton that live in the ocean, or the Paramecium, shown in Figure below , are unicellular, made of just one cell. Other organisms have millions, billions, or trillions of cells.
A diagram in which the numerical values of variables are represented by the height or length of lines or rectangles of equal width is called?	circle graph	pie chart	venn diagram	bar graph	Bar graphs are especially useful for comparing values for different types of things. The bar graph in Figure below shows the number of vehicles of each type that passed the checkpoint.
What opens two strands of dna?	chromosome	replication	adenylate	helicase	DNA replication. The two DNA strands are opened by helicase. The strands are held open by a single strand of binding proteins, preventing premature reannealing. Topoisomerase solves the problem caused by tension generated by winding/unwinding of DNA. This enzyme wraps around DNA and makes a cut permitting the helix to spin and relax. Once DNA is relaxed, topoisomerase reconnects broken strands. DNA primase synthesizes a short RNA primer which initiates the Okazaki fragment. Okazaki fragments are attached by DNA ligase.
Vultures, raccoons and blowflies are examples of what?	consumer	producer	predator	scavengers	Scavengers consume the soft tissues of dead animals. Examples of scavengers include vultures, raccoons, and blowflies.
What holds together adenine and thymine?	helium bonds	covalent bonds	potassium bonds	hydrogen bonds	The base-pairing nature of DNA. Adenine always pairs with thymine, and they are held together with two hydrogen bonds. The guanine-cytosine base pair is held together with three hydrogen bonds. Note that one sugar-phosphate backbone is in the 5’ → 3’ direction, with the other strand in the opposite 3’ → 5’ orientation. Notice that the 5'-end begins with a free (not attached to the sugar of another nucleotide) phosphate group, while the 3'-end has a free (not attached to the phosphate group of another nucleotide) deoxyribose sugar.
Approximately 20% of the atmosphere is made of which element?	nitrogen	hydrogen	carbon	oxygen	Approximately 20% of the atmosphere is oxygen. This gas is essential for life. In environments where oxygen is in low supply, it can be provided from a tank. Since gases are very compressible, a large amount of oxygen can be stored in a relatively small container. When it is released, the volume expands and the pressure decreases. The gas is then available for breathing under normal pressure.
Compound forms when atoms of nonmetals form molecules that are held together by what?	dissonance bonds	phenotype bonds	magnetic bonds	covalent bonds	Compound forms when atoms of nonmetals form molecules that are held together by covalent bonds.
The bony socket that houses the eyeball and associated muscles is called?	acetabulum	cavity	glenoid fossa	orbit	The Orbit The orbit is the bony socket that houses the eyeball and contains the muscles that move the eyeball or open the upper eyelid. Each orbit is cone-shaped, with a narrow posterior region that widens toward the large anterior opening. To help protect the eye, the bony margins of the anterior opening are thickened and somewhat constricted. The medial walls of the two orbits are parallel to each other but each lateral wall diverges away from the midline at a 45° angle. This divergence provides greater lateral peripheral vision. The walls of each orbit include contributions from seven skull bones (Figure 7.16). The frontal bone forms the roof and the zygomatic bone forms the lateral wall and lateral floor. The medial floor is primarily formed by the maxilla, with a small contribution from the palatine bone. The ethmoid bone and lacrimal bone make up much of the medial wall and the sphenoid bone forms the posterior orbit. At the posterior apex of the orbit is the opening of the optic canal, which allows for passage of the optic nerve from the retina to the brain. Lateral to this is the elongated and irregularly shaped superior orbital fissure, which provides passage for the artery that supplies the eyeball, sensory nerves, and the nerves that supply the muscles involved in eye movements.
Humans cannot digest what primary structural material of plants, which is one of the most abundant organic substances on earth?	zinc	sulfur	carbonate	cellulose	Starches (a) and cellulose (b) differ in the connection between glucose units and the amount of branching in the molecule. Starches can be coiled or branched, whereas cellulose, the primary structural material of plants, has long, unbranched chains held together by hydrogen bonds. Cellulose is the primary structural material of plants and one of the most abundant organic substances on Earth. Because our enzymes are not able to hydrolyze the bonds between the glucose units in cellulose, we are unable to digest it. A recently marketed product containing a high percentage of cellulose was sold as a dietetic substance for rapid weight loss, but those who consumed it experienced severe intestinal discomfort because the cellulose could not be digested. The product was quickly removed from the market.
Myofibrils are long cylindrical structures that lie parallel to and run the entire length of what fibers?	heart muscle fibers	uplift muscle fibers	luminous muscle fibers	skeletal muscle fibers	Skeletal Muscle Fiber Structure and Function Each skeletal muscle fiber is a skeletal muscle cell. Within each muscle fiber are myofibrils, long cylindrical structures that lie parallel to the muscle fiber. Myofibrils run the entire length of the muscle fiber. They attach to the plasma membrane, called the sarcolemma, at their ends, so that as myofibrils shorten, the entire muscle cell contracts (Figure 16.18).
The inside of the small intestine has many folds, called villi. microvilli are lined with blood vessels as well as lymphatic vessels. the inside of the small intestine is called this?	osmotic	reticular	porous	lumen	The inside of the small intestine has many folds, called villi. Microvilli are lined with blood vessels as well as lymphatic vessels. The inside of the small intestine is called the lumen. Figure 34.19 Which of the following statements about digestive processes is true? a. Amylase, maltase and lactase in the mouth digest carbohydrates. Trypsin and lipase in the stomach digest protein. Bile emulsifies lipids in the small intestine. No food is absorbed until the small intestine.
What broad animal group is thought to have evolved from theropod dinosaurs around 150 million years ago?	reptiles	insects	mammals	birds	Birds are thought to have evolved from theropod dinosaurs around 150 million years ago. Their ancestor may have been similar to the extinct theropod Deinonychus, whose fossils convinced most scientists that birds evolved from dinosaurs. Scientist still don’t know how or why wings and flight evolved, but they continue to search for answers.
What is the protein in red blood cells which transports oxygen around the body?	hematocrit	plasma	hydrogen	hemoglobin	What do you see when you look at this picture? Is it just a mass of tangled ribbons? Look closely. It’s actually a complex pattern of three-dimensional shapes. It represents the structure of a common chemical found inside living cells. The chemical is a protein called hemoglobin. It is the protein in red blood cells which transports oxygen around the body.
Organs involved in digestion that do not have food pass through them are called?	bypass organs	vestigial organs	layer organs	accessory organs	Other organs involved in digestion include the liver, gall bladder, and pancreas. They are called accessory organs because food does not pass through them. Instead, they secrete or store substances needed for digestion.
At a synapse, what objects are released to carry a nerve impulse from one neuron to the next?	microorganisms	viruses	receptors	neurotransmitters	Laura Guerin. At a synapse, neurotransmitters are released to carry a nerve impulse from one neuron to the next . CC BY-NC 3.0.
All cells have a jellylike substance in which subcellular components are suspended. what is that substance?	cortisol	glycerol	plasma	cytosol
In physics, when one subtracts the frictional force from the applied force what is the result?	kinetic force	rolled force	quarter force	net force	The net force is found by subtracting the frictional force from the applied force.
What is the term for the force that brings objects toward the earth?	centrifugal	weight	light	gravity
Skyscrapers and other large structures built on soft ground must be anchored to what, located below the ground surface?	water table	ocean floor	groundwater	bedrock	Skyscrapers and other large structures built on soft ground must be anchored to bedrock. Sometimes the bedrock lies hundreds of meters below the ground surface.
When your brain senses that your body temperature is increasing, it sends messages to the blood vessels in the skin to increase in what?	weight	surface	height	diameter	The cardiovascular system also plays a role in maintaining body temperature. It helps to keep you warm by moving warm blood around your body. Your blood vessels also control your body temperature to keep you from getting too hot or too cold. When your brain senses that your body temperature is increasing, it sends messages to the blood vessels in the skin to increase in diameter. Increasing the diameter of the blood vessels increases the amount of blood and heat that moves near the skin's surface. The heat is then released from the skin. This helps you cool down. What do you think your blood vessels do when your body temperature is decreasing?.
Which fish has a round sucker used to suck the blood of other fish?	moray	shark	abalone	lamprey	Lampreys Lampreys lack scales but have fins and a partial backbone. Their mouth is surrounded by a large round sucker with teeth. They use the sucker to suck the blood of other fish. lampreys.
What type of change is undergone when the physical properties of a substance are changed?	atmospheric	thermal	genetic	physical	Any time the physical properties of a substance are changed, we can say the substance has undergone a physical change . All substances undergo physical changes where there is a change in the form of the substance but not in its chemical composition. For instance, the grinding of granular sugar into powdered sugar is a physical change. Similarly, dissolving sugar in water is a physical change. We can also use physical changes to separate mixtures into their components. There are a variety of methods used, and the best procedure depends largely on the nature of the mixture. Depending on the states of matter involved, the relative sizes of the mixtures components, and whether the mixture is homogeneous or heterogeneous will determine the necessary separation technique.
Digestive enzymes are released, or secreted, by the organs of which body system?	endocrine system	nervous system	urinary system	digestive system	Digestive enzymes are released, or secreted, by the organs of the digestive system. These enzymes include proteases that digest proteins, and nucleases that digest nucleic acids. Examples of digestive enzymes are:.
When water is aerated it can provide a plant's roots with what gas for cellular respiration?	carbon dioxide	nitrogen	carbon	oxygen
Calcium ion is an example of what kind of messenger?	first	third	fourth	second	Second Messengers Second messengers are small molecules that propagate a signal after it has been initiated by the binding of the signaling molecule to the receptor. These molecules help to spread a signal through the cytoplasm by altering the behavior of certain cellular proteins. Calcium ion is a widely used second messenger. The free concentration of calcium ions (Ca2+) within a cell is very low because ion pumps in the plasma membrane continuously use adenosine-5'-triphosphate (ATP) to remove it. For signaling purposes, Ca2+ is stored in cytoplasmic vesicles, such as the endoplasmic reticulum, or accessed from outside the cell. When signaling occurs, ligand-gated calcium ion channels allow the higher levels of Ca2+ that are present outside the cell (or in intracellular storage compartments) to flow into the cytoplasm, which raises the concentration of cytoplasmic Ca2+. The response to the increase in Ca2+ varies, depending on the cell type involved. For example, in the β-cells of the pancreas, Ca2+ signaling leads to the release of insulin, and in muscle cells, an increase in Ca 2+ leads to muscle contractions. Another second messenger utilized in many different cell types is cyclic AMP (cAMP). Cyclic AMP is synthesized by the enzyme adenylyl cyclase from ATP (Figure 9.12). The main role of cAMP in cells is to bind to and activate an enzyme called cAMP-dependent kinase (A-kinase). A-kinase regulates many vital metabolic pathways: It phosphorylates serine and threonine residues of its target proteins, activating them in the process. A-kinase is found in many different types of cells, and the target proteins in each kind of cell are different. Differences give rise to the variation of the responses to cAMP in different cells.
Aspirin and ibuprofen reduce pain by inhibiting the synthesis of what?	hormones	triglycerides	lipids	prostaglandins
What unit do astronomers use to describe distances in space?	gravity years	quantum years	light months	light years	Astronomers use light years as the unit to describe distances in space. Remember that a light year is the distance light travels in one year.
What is the process by which water moves through semi-permeable membranes from one part of the body to another?	mitosis	diffusion	electrolysis	osmosis	26.1 \| Body Fluids and Fluid Compartments By the end of this section, you will be able to: • Explain the importance of water in the body • Contrast the composition of the intracellular fluid with that of the extracellular fluid • Explain the importance of protein channels in the movement of solutes • Identify the causes and symptoms of edema The chemical reactions of life take place in aqueous solutions. The dissolved substances in a solution are called solutes. In the human body, solutes vary in different parts of the body, but may include proteins—including those that transport lipids, carbohydrates, and, very importantly, electrolytes. Often in medicine, a mineral dissociated from a salt that carries an electrical charge (an ion) is called and electrolyte. For instance, sodium ions (Na+) and chloride ions (Cl-) are often referred to as electrolytes. In the body, water moves through semi-permeable membranes of cells and from one compartment of the body to another by a process called osmosis. Osmosis is basically the diffusion of water from regions of higher concentration to regions of lower concentration, along an osmotic gradient across a semi-permeable membrane. As a result, water will move into and out of cells and tissues, depending on the relative concentrations of the water and solutes found there. An appropriate balance of solutes inside and outside of cells must be maintained to ensure normal function.
What cells are the basis of nervous tissue?	osteoclasts	erythrocytes	lipocytes	neurons	Neurons Neurons are the cells considered to be the basis of nervous tissue. They are responsible for the electrical signals that communicate information about sensations, and that produce movements in response to those stimuli, along with inducing thought processes within the brain. An important part of the function of neurons is in their structure, or shape. The threedimensional shape of these cells makes the immense numbers of connections within the nervous system possible.
Pure carbon can exist in different forms, depending on how its atoms are arranged. the forms include diamond, graphite, and what else?	ligands	calcites	lead	fullerenes	Pure carbon can exist in different forms, depending on how its atoms are arranged. The forms include diamond, graphite, and fullerenes. All three forms exist as crystals, but they have different structures. Their different structures, in turn, give them different properties. You can learn more about them in Table below .
Which cavity, filled with lubricating serous fluid, lies between the epicardium and the pericardium?	thoracic cavity	cranial cavity	oral cavity	pericardial cavity	and is part of the heart wall. The pericardial cavity, filled with lubricating serous fluid, lies between the epicardium and the pericardium. In most organs within the body, visceral serous membranes such as the epicardium are microscopic. However, in the case of the heart, it is not a microscopic layer but rather a macroscopic layer, consisting of a simple squamous epithelium called a mesothelium, reinforced with loose, irregular, or areolar connective tissue that attaches to the pericardium. This mesothelium secretes the lubricating serous fluid that fills the pericardial cavity and reduces friction as the heart contracts. Figure 19.5 illustrates the pericardial membrane and the layers of the heart.
Layers of what create a volcano?	crust	rock	limestone	lava	Magma beneath a volcano erupts onto the volcano’s surface. Layer upon layer of lava creates a volcano.
In amphibians, reptiles, birds, and mammals, blood flow is directed in two circuits: one through the lungs and back to the heart, which is called what?	metabolic circulation	systemic circulation	sensory circulation	pulmonary circulation	In amphibians, reptiles, birds, and mammals, blood flow is directed in two circuits: one through the lungs and back to the heart, which is called pulmonary circulation, and the other throughout the rest of the body and its organs including the brain (systemic circulation). In amphibians, gas exchange also occurs through the skin during pulmonary circulation and is referred to as pulmocutaneous circulation. As shown in Figure 40.4b, amphibians have a three-chambered heart that has two atria and one ventricle rather than the two-chambered heart of fish. The two atria (superior heart chambers) receive blood from the two different circuits (the lungs and the systems), and then there is some mixing of the blood in the heart’s ventricle (inferior heart chamber), which reduces the efficiency of oxygenation. The advantage to this arrangement is that high pressure in the vessels pushes blood to the lungs and body. The mixing is mitigated by a ridge within the ventricle that diverts oxygen-rich blood through the systemic circulatory system and deoxygenated blood to the pulmocutaneous circuit. For this reason, amphibians are often described as having double circulation. Most reptiles also have a three-chambered heart similar to the amphibian heart that directs blood to the pulmonary and systemic circuits, as shown in Figure 40.4c. The ventricle is divided more effectively by a partial septum, which results in less mixing of oxygenated and deoxygenated blood. Some reptiles (alligators and crocodiles) are the most primitive animals to exhibit a four-chambered heart. Crocodilians have a unique circulatory mechanism where the heart shunts blood from the lungs toward the stomach and other organs during long periods of submergence, for instance, while the animal waits for prey or stays underwater waiting for prey to rot. One adaptation includes two main arteries that leave the same part of the heart: one takes blood to the lungs and the other provides an alternate route to the stomach and other parts of the body. Two other adaptations include a hole in the heart between the two ventricles, called the foramen of Panizza, which allows blood to move from one side of the heart to the other, and specialized connective tissue that slows the blood flow to the lungs. Together these adaptations have made crocodiles and alligators one of the most evolutionarily successful animal groups on earth. In mammals and birds, the heart is also divided into four chambers: two atria and two ventricles, as illustrated in Figure 40.4d. The oxygenated blood is separated from the deoxygenated blood, which improves the efficiency of double circulation and is probably required for the warm-blooded lifestyle of mammals and birds. The four-chambered heart of birds and mammals evolved independently from a three-chambered heart. The independent evolution of the same or a similar biological trait is referred to as convergent evolution.
Non-human organisms that mainly consume plants/other primary producers are known as what?	omnivores	amphibians	carnivores	herbivores
In the microbiology lab, what technique refers to the procedures that are carried out under sterile conditions?	ionization	personal hygiene	experimental control	aseptic	In the microbiology lab, aseptic technique refers to the procedures that are carried out under sterile conditions. Scientists who study microbes are called microbiologists. Microbiologists must carry out their lab work using the aseptic technique to prevent microbial contamination of themselves, contamination of the environment they are working in, including work surfaces or equipment, and contamination of the sample they are working on. Bacteria live on just about every surface on Earth, so if a scientist wants to grow a particular type of bacterium in the lab, he or she needs to be able to sterilize their equipment to prevent contamination by other bacteria or microorganisms. The aseptic technique is also used in medicine, where it is important to keep the human body free of contamination.
Connecting a magnesium rod to an underground steel pipeline protects the pipeline from corrosion. because magnesium (e° = −2.37 v) is much more easily oxidized than iron (e° = −0.45 v), the mg rod acts as the anode in a what?	voltaic cell	anode cell	stimulation cell	galvanic cell	Connecting a magnesium rod to an underground steel pipeline protects the pipeline from corrosion. Because magnesium (E° = −2.37 V) is much more easily oxidized than iron (E° = −0.45 V), the Mg rod acts as the anode in a galvanic cell. The pipeline is therefore forced to act as the cathode at which oxygen is reduced. The soil between the anode and the cathode acts as a salt bridge that completes the electrical circuit and maintains electrical neutrality. As Mg(s) is oxidized to Mg2+ at the anode, anions in the soil, such as nitrate, diffuse toward the anode to neutralize the positive charge. Simultaneously, cations in the soil, such as H+ or NH4+, diffuse toward the cathode, where they replenish the protons that are consumed as oxygen is reduced. A similar strategy uses many miles of somewhat less reactive zinc wire to protect the Alaska oil pipeline.
Matrix is the term for the fluid-filled interior of what structure, where most of the cell’s atp is made?	enzyme	nucleus	Golgi apparatus	mitochondria	As the Figure below (a) and (b) shows, a mitochondrion has two phospholipids membranes. The smooth outer membrane separates the mitochondrion from the cytosol. The inner membrane has many folds, called cristae . These cristae greatly increase the membrane surface area for integral proteins. Many proteins involved in cellular respiration are embedded in this inner membrane. The greater surface area allows more proteins to be located there, resulting in more cellular respiration reactions, and more ATP synthesis. ATP is produced by the enzyme ATP synthase, which is a membrane protein of the mitochondria inner membrane. The fluid-filled inside of the mitochondrian, called matrix , is where most of the cell’s ATP is made.

Compounds that are capable of accepting electrons, such as o 2 or f2, are called what?

residues

antioxidants

Oxygen

oxidants

Oxidants and Reductants Compounds that are capable of accepting electrons, such as O 2 or F2, are calledoxidants (or oxidizing agents) because they can oxidize other compounds. In the process of accepting electrons, an oxidant is reduced. Compounds that are capable of donating electrons, such as sodium metal or cyclohexane (C6H12), are calledreductants (or reducing agents) because they can cause the reduction of another compound. In the process of donating electrons, a reductant is oxidized. These relationships are summarized in Equation 3.30: Equation 3.30 Saylor URL: http://www. saylor. org/books.

What term in biotechnology means a genetically exact copy of an organism?

phenotype

adult

male

clone

But transgenic animals just have one novel gene. What about an animal with a whole new genome? Could a clone , a genetically exact copy of an organism, be developed using techniques associated with biotechnology? It could be argued that human cloning is one of the inevitable outcomes of modern biotechnology. It "simply" involves the removal of the nucleus from a somatic cell and its placement into an unfertilized egg cell whose nucleus has either been deactivated or removed. This new cell would mimic the zygote, the first diploid cell of a new organism. This new zygote is allowed to become established, and a few days later is placed into the uterus of a surrogate mother. Theoretically this would result in an individual genetically identical to the donor. Obviously, there are many ethical and legal issues associated with human cloning, and of course, it is not a "simple" procedure. But animal cloning is arguably a different story.

What is the height above or below sea level called?

variation

depth

latitude

elevation

As you know, the surface of Earth is not flat. Some places are high, and some places are low. For example, mountain ranges like the Sierra Nevada in California or the Andes in South America are high above the surrounding areas. An accurate location must take into account the third dimension. Elevation is the height above or below sea level. Sea level refers to the height of the ocean’s surface. This is the midpoint between high and low tide. Sea level can vary from place to place, but scientists base their elevation measurements on the average, or mean, sea level to make sure they have a standard reference point.

The bird ancestor that lived in trees developed what feature commonly associated with birds?

beaks

tails

webbed feet

wings

Wings evolved in a bird ancestor that lived in trees. Thus, wings are modified arms that helped the animal glide from branch to branch.

What term means the amount of water vapor in the air?

ambient

temperature

pressure

humidity

Humidity is the amount of water vapor in the air. High humidity increases the chances of clouds and precipitation.

Paracrine signals move by what method through the extracellular matrix?

transfusion

osmosis

deposition

diffusion

Paracrine Signaling Signals that act locally between cells that are close together are called paracrine signals. Paracrine signals move by diffusion through the extracellular matrix. These types of signals usually elicit quick responses that last only a short amount of time. In order to keep the response localized, paracrine ligand molecules are normally quickly degraded by enzymes or removed by neighboring cells. Removing the signals will reestablish the concentration gradient for the signal, allowing them to quickly diffuse through the intracellular space if released again. One example of paracrine signaling is the transfer of signals across synapses between nerve cells. A nerve cell consists of a cell body, several short, branched extensions called dendrites that receive stimuli, and a long extension called an axon, which transmits signals to other nerve cells or muscle cells. The junction between nerve cells where signal transmission occurs is called a synapse. A synaptic signal is a chemical signal that travels between nerve cells. Signals within the nerve cells are propagated by fast-moving electrical impulses. When these impulses reach the end of the axon, the signal continues on to a dendrite of the next cell by the release of chemical ligands called neurotransmitters by the presynaptic cell (the cell emitting the signal). The neurotransmitters are transported across the very small distances between nerve cells, which are called chemical synapses (Figure 9.3). The small distance between nerve cells allows the signal to travel quickly; this enables an immediate response, such as, Take your hand off the stove! When the neurotransmitter binds the receptor on the surface of the postsynaptic cell, the electrochemical potential of the target cell changes, and the next electrical impulse is launched. The neurotransmitters that are released into the chemical synapse are degraded quickly or get reabsorbed by the presynaptic cell so that the recipient nerve cell can recover quickly and be prepared to respond rapidly to the next synaptic signal.

Presence of a cell wall, large central vacuole, and organelles called plastids distinguish what type of cell?

heterotroph

animal

reproductive

plant

All but one of the structures described above are found in plant cells as well as animal cells. The only exception is centrioles, which are not found in plant cells. Plant cells have three additional structures that are not found in animals cells. These include a cell wall, large central vacuole, and organelles called plastids. You can see these structures in the model of a plant cell in Figure below . You can also see them in the interactive plant cell at this link:.

Digestion of proteins begins with acids in what organ?

brain

colon

liver

stomach

24.4 Protein Metabolism Digestion of proteins begins in the stomach, where HCl and pepsin begin the process of breaking down proteins into their constituent amino acids. As the chyme enters the small intestine, it mixes with bicarbonate and digestive enzymes. The bicarbonate neutralizes the acidic HCl, and the digestive enzymes break down the proteins into smaller peptides and amino acids. Digestive hormones secretin and CCK are released from the small intestine to aid in digestive processes, and digestive proenzymes are released from the pancreas (trypsinogen and chymotrypsinogen). Enterokinase, an enzyme located in the wall of the small intestine, activates trypsin, which in turn activates chymotrypsin. These enzymes liberate the individual amino acids that are then transported via sodium-amino acid transporters across the intestinal wall into the cell. The amino acids are then transported into the bloodstream for dispersal to the liver and cells throughout the body to be used to create new proteins. When in excess, the amino acids are processed and stored as glucose or ketones. The nitrogen waste that is liberated in this process is converted to urea in the urea acid cycle and eliminated in the urine. In times of starvation, amino acids can be used as an energy source and processed through the Krebs cycle.

Many species of rotifers exhibit haplodiploidy, which is a method of what?

respiration

circulation

digestion

gender determination

Watch this video (http://openstaxcollege. org/l/rotifers) to see rotifers feeding. Rotifers are pseudocoelomates commonly found in fresh water and some salt water environments throughout the world. Figure 28.17 shows the anatomy of a rotifer belonging to class Bdelloidea. About 2,200 species of rotifers have been identified. Rotifers are dioecious organisms (having either male or female genitalia) and exhibit sexual dimorphism (males and females have different forms). Many species are parthenogenic and exhibit haplodiploidy, a method of gender determination in which a fertilized egg develops into a female and an unfertilized egg develops into a male. In many dioecious species, males are short-lived and smaller with no digestive system and a single testis. Females can produce eggs that are capable of dormancy for protection during harsh environmental conditions.

What is the most abundant metal of the earth's crust?

magnetite

calcium

copper

aluminum

Metals represent approximately 25% of the elemental makeup of the Earth's crust. The bulk of these metals, primarily aluminum, iron, calcium, sodium, potassium, and magnesium, are typically found in combined form. The most abundant metal is aluminum, which occurs almost exclusively as the ionic mineral bauxite. The other most common metals, including iron, sodium, potassium, magnesium, and calcium, are also found primarily as the cationic portion of an ionic compound. Very few metals actually occur naturally as pure substances. The ones that do are often referred to as precious or semi-precious metals.

What is the term for the total kinetic energy of moving particles of matter?

Newton's energy

heavy energy

mechanical energy

thermal energy

The total kinetic energy of moving particles of matter is called thermal energy.

Chemical reactions involve a transfer of heat energy. measured in what?

thermals

amps

amperes

joules

Chemical reactions involve a transfer of heat energy. Measured in joules.

Most fungi get organic compounds from what?

carnivorous organisms

inorganic material

living organisms

dead organisms

Most fungi get organic compounds from dead organisms. They are decomposers called saprotrophs. A saprotroph feeds on any remaining organic matter after other decomposers do their work. Fungi use enzymes to digest organic remains and then absorb the resulting organic compounds. As decomposers, fungi are vital for the health of ecosystems. They break down nonliving organic matter and release the nutrients into the soil. Plants can then use the nutrients and pass them on to herbivores and other consumers.

Pairs of nitrogenous bases are attached to each other by?

magnetism

potassium bonds

ionic bonds

hydrogen bonds

The strength of a base depends on the concentration of _______ it produces when dissolved in water?

monoxide ions

combustion ions

calcium ions

hydroxide ions

The strength of a base depends on the concentration of hydroxide ions it produces when dissolved in water. For example, sodium hydroxide completely breaks down into ions in water, so it is a strong base. However, only a fraction of ammonia breaks down into ions, so it is a weak base.

Organisms that live deep in the ocean must be able to withstand what?

tsunamis

the sun

significant water pressure

extreme water pressure

Organisms that live deep in the ocean must be able to withstand extreme water pressure, very cold water, and complete darkness. However, even here, thriving communities of living things can be found. Organisms cluster around hydrothermal vents in the ocean floor. The vents release hot water containing chemicals that would be toxic to most other living things. The producers among them are single-celled chemoautotrophs. They make food using energy stored in the chemicals. The tube worms in this chapter's opening photo depend on these chemoautotrophs for food.

What instrument is used to make very sensitive mass measurements in a laboratory, usually in grams?

scale

speedometer

thermometer

analytical balance

An analytical balance makes very sensitive mass measurements in a laboratory, usually in grams.

The lens focuses light on the retina , which covers the back of the inside of the eye. the retina has light-sensing photoreceptor cells called?

tubes and rods

cones and tubes

holes and cones

rods and cones

The lens focuses light on the retina , which covers the back of the inside of the eye. The retina has light-sensing photoreceptor cells called rods and cones. Rods let us see in dim light. Cones let us detect light of different colors.

Temperature, water, soil, and air are examples of nonliving factors of an ecosystem, also termed what?

diverse factors

nucleic factors

conditional factors

abiotic factors

Ecology is the study of ecosystems. That is, ecology is the study of how living organisms interact with each other and with the nonliving part of their environment. An ecosystem consists of all the nonliving factors and living organisms interacting in the same habitat . Recall that living organisms are biotic factors . The biotic factors of an ecosystem include all the populations in a habitat, such as all the species of plants, animals, and fungi, as well as all the micro-organisms. Also recall that the nonliving factors are called abiotic factors . Abiotic factors include temperature, water, soil, and air.

Which kind of muscle regulates air flow in lungs?

alveoli

vascular

striated

smooth

Smooth muscle regulates air flow in lungs.

What type of bonds are formed by the side-to-side overlap of p orbitals?

theta bonds

sigma bonds

omega bonds

pi bonds

Sigma bonds are formed by the end-to-end overlap of bonding orbitals. Pi bonds are formed by the side-to-side overlap of p orbitals. Single bonds are normally sigma bonds. A double or triple bond consists of one sigma bond and either one or two pi bonds.

What is another name for the vertebral column?

brain stem

nerve column

pillar

backbone

animal in Phylum Chordata that has a vertebral column, or backbone.

The temperature at which a substance melts is called its what point?

freezing

boiling

change

melting

The temperature at which a substance melts is called its melting point. Melting point is a physical property of matter. The gold pictured in the Figure above , for example, has a melting point of 1064°C. This is a high melting point, and most other metals also have high melting points. The melting point of ice, in comparison, is much lower at 0°C. Many substances have even lower melting points. For example, the melting point of oxygen is -222°C.

Humans are among the most versatile of mammals with what type of diet?

vegetarian

carnivore

herbivore

omnivore

Solute potential is also called osmotic potential because solutes affect the direction of what?

electrolysis

permeability

electrolysis

osmosis

Fungi, such as black bread mold (rhizopus nigricans), have haploid-dominant what?

mutations

birth cycles

gene pools

life cycles

Figure 11.9 Fungi, such as black bread mold (Rhizopus nigricans), have haploid-dominant life cycles. The haploid multicellular stage produces specialized haploid cells by mitosis that fuse to form a diploid zygote. The zygote undergoes meiosis to produce haploid spores. Each spore gives rise to a multicellular haploid organism by mitosis. (credit “zygomycota” micrograph: modification of work by “Fanaberka”/Wikimedia Commons).

The electrode at which oxidation occurs is called?

calomel

diode

cathode

the anode

The electrode at which oxidation occurs is called the anode . The zinc anode gradually diminishes as the cell operates due to the loss of zinc metal. The zinc ion concentration in the half-cell increases. Because of the production of electrons at the anode, it is labeled as the negative electrode.

The lens and other parts of the eye work together to focus a real image on what eye structure?

cornea

iris

pupil

retina

As just described, the eyes collect and focus visible light. The lens and other structures of the eye work together to focus a real image on the retina. The image is upside-down and reduced in size, as you can see in Figure below . The image reaches the brain as electrical signals that travel through the optic nerve. The brain interprets the signals as shape, color, and brightness. It also interprets the image as though it were right-side up. The brain does this automatically, so what we see is always right-side up. The brain also “tells” us what we are seeing.

What is required to move or change matter from one state to another?

evolution

food

gravity

energy

Energy provides the ability to move or change matter from one state to another (for example, from solid to liquid). Every living thing needs energy to live and grow. Your body gets its energy from food, but that is only a small part of the energy you use every day. Cooking your food takes energy, and so does keeping it cold in the refrigerator or the freezer. The same is true for heating or cooling your home. Whether you are turning on a light in the kitchen or riding in a car to school, you are using energy. Billions of people all around the world use energy, so there is a huge demand for resources to provide all of this energy. Why do we need so much energy? The main reason is that almost everything that happens on Earth involves energy.

What contains positive protons and neutral neutrons?

epidermis

electrons

ions

nucleus

The nucleus is at the center of the atom. It contains positive protons and neutral neutrons. Negative electrons constantly move about the nucleus.

Natural gas is the predominately made up of?

sulfur

hydrogen

carbon

methane

Natural gas is mostly methane. Natural gas is usually found with petroleum. People prefer to burn natural gas when possible because it is relatively clean.

Which organs control the amount of water, ions, and other substances in the blood by excreting more or less of them in urine?

ears

lungs

tongue

kidneys

The kidneys play many vital roles in homeostasis. They filter all the blood in the body many times each day and produce a total of about 1.5 liters of urine. The kidneys control the amount of water, ions, and other substances in the blood by excreting more or less of them in urine. The kidneys also secrete hormones that help maintain homeostasis. Erythropoietin, for example, is a kidney hormone that stimulates bone marrow to produce red blood cells when more are needed. The kidneys themselves are also regulated by hormones. For example, antidiuretic hormone from the hypothalamus stimulates the kidneys to produce more concentrated urine when the body is low on water.

What is a therian mammal in which the embryo is born at an early, immature stage?

carnivore

rodent

bat

a marsupial

Marsupials have a different way of reproducing that reduces the mother’s risks. A marsupial is a therian mammal in which the embryo is born at an early, immature stage. The embryo completes its development outside the mother’s body in a pouch on her belly. Only a minority of therian mammals are marsupials. They live mainly in Australia. Examples of marsupials are pictured in Figure below .

What are fungi which feed on living cells called?

symbiotic

static

predatory

parasitic

23.24 Nutrition Fungi are saprophytes. When they find a source of food (e. dead wood, orange peel) , they decompose it and digest it. The enzymes break down larger organic molecules in the substrate into smaller molecules. These smaller molecules diffuse into the fungus, where they are used to allow growth and repair. Fungi which feed on living cells are parasitic. For example, athlete's foot grows on the human foot. These kinds of fungi produce hyphae called haustoria, which can penetrate host cells without immediately killing them. However, they are friendlier species of fungi. Many fungi live symbiotically with plants or animals. For example, most trees have fungi living in close contact with their roots. In this relationship, known as a mycorrhiza, there are many benefits: • Growing around the plant roots and often entering plant cells, the hyphae absorb minerals from the soil and release them in the roots. The fungi gets its source of food (organic nutrients) while delivering food to the plant. • The mycelium here would increase the surface area, thus the absorptive surface, of the plant roots. • The fungal cells help to maintain air and water flow in the soil around the roots. • The fungi may prevent other potentially pathogenic fungi to attack the tree.

What is the diffusion of water through a semipermeable membrane down its concentration gradient

Permable

nutrients

mirrors

osmosis

Figure 3.7 Osmosis Osmosis is the diffusion of water through a semipermeable membrane down its concentration gradient. If a membrane is permeable to water, though not to a solute, water will equalize its own concentration by diffusing to the side of lower water concentration (and thus the side of higher solute concentration). In the beaker on the left, the solution on the right side of the membrane is hypertonic.

In phyisics, what is considered to be the rotational version of force?

pressure

work

energy

torque

Torque is equal to the cross product as stated above. In general, one can simplify by saying that the torque is equal to the force acting on the object multiplied by the perpendicular distance from the application of the force to the rotational axis. Say you had a seesaw. It is easier to exert torque, get the seesaw to move, if you pushed on the board near the end rather than near the middle. It is the rotational version of Force.

Skeletal muscles are attached to the skeleton by tough connective tissues called what?

cords

fibers

veins

tendons

Skeletal muscles are attached to the skeleton by tough connective tissues called tendons (see Figure above ). Many skeletal muscles are attached to the ends of bones that meet at a joint . The muscles span the joint and connect the bones. When the muscles contract, they pull on the bones, causing them to move.

What is the ability to see called?

hearing

thought

smell

vision

The ability to see is called vision . This ability depends on more than healthy eyes. It also depends on certain parts of the brain, because the brain and eyes work together to allow us to see. The eyes collect and focus visible light. The lens and other structures of the eye work together to focus an image on the retina. The image is upside-down and reduced in size, as you can see in the Figure below . Cells in the retina change the image to electrical signals that travel to the brain through the optic nerve. The brain interprets the electrical signals as shape, color, and brightness. It also interprets the image as though it were right-side up. The brain does this automatically, so what we see always appears right-side up. The brain also interprets what we are seeing.

Which two major innovations allowed seed plants to reproduce in the absence of water?

salt and pollen

bee and pollen

root and pollen

seed and pollen

CHAPTER SUMMARY 26.1 Evolution of Seed Plants Seed plants appeared about one million years ago, during the Carboniferous period. Two major innovations—seed and pollen—allowed seed plants to reproduce in the absence of water. The gametophytes of seed plants shrank, while the sporophytes became prominent structures and the diploid stage became the longest phase of the lifecycle. Gymnosperms became the dominant group during the Triassic. In these, pollen grains and seeds protect against desiccation. The seed, unlike a spore, is a diploid embryo surrounded by storage tissue and protective layers. It is equipped to delay germination until growth conditions are optimal. Angiosperms bear both flowers and fruit. The structures protect the gametes and the embryo during its development. Angiosperms appeared during the Mesozoic era and have become the dominant plant life in terrestrial habitats.

Water can be broken down into hydrogen and oxygen gases by the addition of what?

demand

motion

mineral

energy

Chemistry in Everyday Life Decomposition of Water / Production of Hydrogen Water consists of the elements hydrogen and oxygen combined in a 2 to 1 ratio. Water can be broken down into hydrogen and oxygen gases by the addition of energy. One way to do this is with a battery or power supply, as shown in (Figure 1.15).

In humans, the only haploid cells are what reproductive cells?

uteral and sperm

dna and egg

sperm and dna

sperm and egg

The life cycle of a plant is very different from the life cycle of an animal. Humans are made entirely of diploid cells (cells with two sets of chromosomes, referred to as ''2n''). Our only cells that are haploid cells (cells with one set of chromosomes, ''n'') are sperm and egg cells. Plants, however, can live when they are are at the stage of having haploid cells or diploid cells. If a plant has a haploid chromosome number of 20, what is the diploid chromosome number? If the diploid chromosome number is 20, what is the haploid number?.

The lithosphere is divided into a dozen major and several minor what?

faults

zones

crystals

plates

The lithosphere is divided into a dozen major and several minor plates. Each plate is named for the continent or ocean basin it contains. Some plates are made of all oceanic lithosphere. A few are all continental lithosphere. But most plates are made of a combination of both.

What are used to indicate the number of atoms of an element that are in the compound?

digits

indices

suffixes

prefixes

Prefixes are used to indicate the number of atoms of an element that are in the compound.

Area, volume, and speed are all examples of what type of units?

known units

fundamental units

calculated measure

derived units

Derived units can be expressed as some combination of base units. Examples of derived units are area, volume, and speed.

Anything moving has what type of energy?

thermal

magnetic

potential

kinetic

Why do the air and sand of Death Valley feel so hot? It’s because their particles are moving very rapidly. Anything that is moving has kinetic energy, and the faster it is moving, the more kinetic energy it has. The total kinetic energy of moving particles of matter is called thermal energy . It’s not just hot things such as the air and sand of Death Valley that have thermal energy. All matter has thermal energy, even matter that feels cold. That’s because the particles of all matter are in constant motion and have kinetic energy.

A skydiver will reach what when the air drag equals their weight?

ending velocity

constant velocity

building velocity

terminal velocity

viscosity. Using the equation of the previous problem, find the viscosity of motor oil in which a steel ball of radius 0.8 mm falls with a terminal speed of 4.32 cm/s. The densities of the ball and the oil are 7.86 and 0.88 g/mL, respectively. A skydiver will reach a terminal velocity when the air drag equals their weight. For a skydiver with high speed and a large body, turbulence is a factor. The drag force then is approximately proportional to the square of the velocity. Taking the drag force to be F D = 1 ρAv 2 and setting this 2 equal to the person’s weight, find the terminal speed for a person falling “spread eagle. ” Find both a formula and a number for v t , with assumptions as to size. A layer of oil 1.50 mm thick is placed between two microscope slides. Researchers find that a force of 5.50×10 −4 N is required to glide one over the other at a speed of 1.00 cm/s when their contact area is 6.00 cm 2 . What is the oil’s viscosity? What type of oil might it be? 42. (a) Verify that a 19.0% decrease in laminar flow through a tube is caused by a 5.00% decrease in radius, assuming that all other factors remain constant, as stated in the text. (b) What increase in flow is obtained from a 5.00% increase in radius, again assuming all other factors remain constant? 43. Example 12.8 dealt with the flow of saline solution in an IV system. (a) Verify that a pressure of 1.62×10 4 N/m 2 is created at a depth of 1.61 m in a saline solution, assuming its density to be that of sea water. (b) Calculate the new flow rate if the height of the saline solution is decreased to 1.50 m. (c) At what height would the direction of flow be reversed? (This reversal can be a problem when patients stand up. ) 44. When physicians diagnose arterial blockages, they quote the reduction in flow rate. If the flow rate in an artery has been reduced to 10.0% of its normal value by a blood clot and the.

What is the adaptation that certain animals use to become less visible to predators and prey?

insulation

skeletons

speed

camouflage

Camouflage by the dead leaf mantis makes it less visible to both its predators and prey. If alarmed, it lies motionless on the rainforest floor of Madagascar, Africa, camouflaged among the actual dead leaves. It eats other animals up to the size of small lizards.

What is another term for blood clotting?

differentiation

adulation

oxidation

coagulation

Positive Feedback Loop A positive feedback loop maintains the direction of the stimulus, possibly accelerating it. Few examples of positive feedback loops exist in animal bodies, but one is found in the cascade of chemical reactions that result in blood clotting, or coagulation. As one clotting factor is activated, it activates the next factor in sequence until a fibrin clot is achieved. The direction is maintained, not changed, so this is positive feedback. Another example of positive feedback is uterine contractions during childbirth, as illustrated in Figure 33.21. The hormone oxytocin, made by the endocrine system, stimulates the contraction of the uterus. This produces pain sensed by the nervous system. Instead of lowering the oxytocin and causing the pain to subside, more oxytocin is produced until the contractions are powerful enough to produce childbirth.

What do you call the study of how organisms interact with their environment and each other?

climatology

biology

biochemistry

ecology

Most biological sciences are specialized areas of study. Biology includes biochemistry, cell biology, microbiology, immunology, genetics, physiology, zoology, ecology, evolutionary biology, and botany. Biochemistry is the study of the chemicals that make up life. Cell biology is the study of life at the level of the cell. Microbiology is the study of microscopic organisms. Immunology is the study of an organism's resistance to disease. Genetics is the study of how organisms pass traits to their offspring. The study of how the human body works is called physiology. Zoology is the study of animals. The study of how organisms interact with their environment and each other is called ecology. Evolutionary biology is the study of how populations and species change over time. Botany is the study of plants. The four unifying principles are important foundations for each and every field of biology. Applied fields of biology such as medicine and genetic research involve many specialized areas of study.

What phenomenon, which is most important in small populations, occurs because the alleles in an offspring generation are a random sample of the alleles in the parent generation?

genetic code

genetic DNA

genetic mutation

genetic drift

Genetic Drift Another way a population’s allele frequencies can change is genetic drift (Figure 11.7), which is simply the effect of chance. Genetic drift is most important in small populations. Drift would be completely absent in a population with infinite individuals, but, of course, no population is this large. Genetic drift occurs because the alleles in an offspring generation are a random sample of the alleles in the parent generation. Alleles may or may not make it into the next generation due to chance events including mortality of an individual, events affecting finding a mate, and even the events affecting which gametes end up in fertilizations. If one individual in a population of ten individuals happens to die before it leaves any offspring to the next generation, all of its genes—a tenth of the population’s gene pool—will be suddenly lost. In a population of 100, that 1 individual represents only 1 percent of the overall gene pool; therefore, it has much less impact on the population’s genetic structure and is unlikely to remove all copies of even a relatively rare allele. Imagine a population of ten individuals, half with allele A and half with allele a (the individuals are haploid). In a stable population, the next generation will also have ten individuals. Choose that generation randomly by flipping a coin ten times and let heads be A and tails be a. It is unlikely that the next generation will have exactly half of each allele. There might be six of one and four of the other, or some different set of frequencies. Thus, the allele frequencies have changed and evolution has occurred. A coin will no longer work to choose the next generation (because the odds are no longer one half for each allele). The frequency in each generation will drift up and down on what is known as a random walk until at one point either all A or all a are chosen and that allele is fixed from that point on. This could take a very long time for a large population. This simplification is not very biological, but it can be shown that real populations behave this way. The effect of drift on frequencies is greater the smaller a population is. Its effect is also greater on an allele with a frequency far from one half. Drift will influence every allele, even those that are being naturally selected.

What is the term for when an embryo fixes itself to the side of the uterus?

exploration

bacterial

parasite

implantation

Implantation occurs when the developing embryo fixes itself to the side of the uterus.

When exposed to ultraviolet, some substances, such as minerals, glow in characteristic visible wavelengths, a process called this?

pigment

plasma

chemical reaction

fluorescence

When exposed to ultraviolet, some substances, such as minerals, glow in characteristic visible wavelengths, a process called fluorescence. So-called black lights emit ultraviolet to cause posters and clothing to fluoresce in the visible. Ultraviolet is also used in special microscopes to detect details smaller than those observable with longer-wavelength visible-light microscopes. Things Great and Small: A Submicroscopic View of X-Ray Production X-rays can be created in a high-voltage discharge. They are emitted in the material struck by electrons in the discharge current. There are two mechanisms by which the electrons create X-rays. The first method is illustrated in Figure 24.18. An electron is accelerated in an evacuated tube by a high positive voltage. The electron strikes a metal plate (e. , copper) and produces X-rays. Since this is a high-voltage discharge, the electron gains sufficient energy to ionize the atom.

What disease occurs when the cell cycle is no longer regulated?

malnutrition

allergy

schizophrenia

cancer

Cancer is a disease that occurs when the cell cycle is no longer regulated. Cancer cells grow rapidly and may form a mass of abnormal cells called a tumor.

What are the little sacs at the end of the bronchioles called?

ganglion

lung

respiratory sacs

alveoli

The bronchioles lead to the alveoli. Alveoli are the little sacs at the end of the bronchioles ( Figure below ). They look like little bunches of grapes. Oxygen is exchanged for carbon dioxide in the alveoli. That means oxygen enters the blood, and carbon dioxide moves out of the blood. The gases are exchanged between the blood and alveoli by simple diffusion.

Circulating the air prevents ethylene from accumulating, and carbon dioxide inhibits synthesis of new what?

cellulose

alcohol

sulfur

ethylene

What is a fiber that is found only in mammals?

feathers

muscle

hair

Hair is a fiber that is found only in mammals. Its main component is keratin. A hair shaft consists of dead, keratin-filled cells that overlap each other like the shingles on a roof (see Figure below ). Like roof shingles, the overlapping cells help shed water from the hair.

What type of plants does human welfare depend greatly on?

fertilizer plants

mosses

ferns

seed plants

30.4 Human welfare depends greatly on seed plants.

What are cells without a nucleus called?

crustal cells

Monocyte Cells

heterogeneous cells

prokaryotic cells

Prokaryotic cells are cells without a nucleus. They are found in single-celled organisms. Eukaryotic cells are cells with a nucleus and other organelles. They are found mainly in multicellular organisms.

The hypothalamus is actually part of the brain, but it also secretes what?

electrolytes

enzymes

acids

hormones

The hypothalamus is actually part of the brain, but it also secretes hormones. Some of its hormones go directly to the pituitary gland in the endocrine system. These hypothalamus hormones tell the pituitary to either secrete or stop secreting its hormones. In this way, the hypothalamus provides a link between the nervous and endocrine systems.

What disease characterized by the extreme swelling of the limbs is caused by infection with a type of roundworm?

fibrosis

pulmonary edema

gigantism

elephantiasis

Roundworms can be free-living organisms, but they are probably best known for their role as significant plant and animal parasites. Most Nematodes are parasitic, with over 16,000 parasitic species described. Heartworms, which cause serious disease in dogs while living in the heart and blood vessels, are a type of roundworm. Roundworms can also cause disease in humans. Elephantiasis, a disease characterized by the extreme swelling of the limbs ( Figure below ), is caused by infection with a type of roundworm.

What is the study of water movement, including waves and ocean currents?

thermal oceanography

theoretical oceanography

experimental oceanography

physical oceanography

There are many branches of oceanography. Physical oceanography is the study of water movement, like waves and ocean currents. Physical oceanographers ask when or if a tsunami will hit a shoreline. Marine geologists look at rocks and structures in the ocean basins. These scientists ask how new ocean crust forms. Chemical oceanographers study the natural elements in ocean water. Chemical oceanographers might be concerned with where carbon dioxide goes in the oceans. Marine biologists look at marine life. There are lots of questions to ask about marine life!.

There are many types of asexual spores. conidiospores are unicellular or multicellular spores that are released directly from the tip or side of this?

goychay

ganglion

idioma

hypha

There are many types of asexual spores. Conidiospores are unicellular or multicellular spores that are released directly from the tip or side of the hypha. Other asexual spores originate in the fragmentation of a hypha to form single cells that are released as spores; some of these have a thick wall surrounding the fragment. Yet others bud off the vegetative parent cell. Sporangiospores are produced in a sporangium (Figure 24.9).

What are the hormones that cause a plant to grow?

pistills

sporozoans

pores

gibberellins

Gibberellins are hormones that cause the plant to grow. When gibberellins are applied to plants by scientists, the stems grow longer. Some gardeners or horticulture scientists add gibberellins to increase the growth of plants. Dwarf plants (small plants), on the other hand, have low levels of gibberellins ( Figure below ). Another function of gibberellins is to stop dormancy (resting time) of seeds and buds. Gibberellins signal that it’s time for a seed to germinate (sprout) or for a bud to open.

What are the smallest structural and functional unit of all living organisms?

proteins

neutrons

lipids

cells

If you zoom in very close on a leaf of a plant, or on the skin on your hand, or a drop of blood, you will find cells, you will find cells ( Figure below ). Cells are the smallest structural and functional unit of all living organisms. Most cells are so small that they are usually visible only through a microscope. Some organisms, like bacteria, plankton that live in the ocean, or the Paramecium, shown in Figure below , are unicellular, made of just one cell. Other organisms have millions, billions, or trillions of cells.

A diagram in which the numerical values of variables are represented by the height or length of lines or rectangles of equal width is called?

circle graph

pie chart

venn diagram

bar graph

Bar graphs are especially useful for comparing values for different types of things. The bar graph in Figure below shows the number of vehicles of each type that passed the checkpoint.

What opens two strands of dna?

chromosome

replication

adenylate

helicase

DNA replication. The two DNA strands are opened by helicase. The strands are held open by a single strand of binding proteins, preventing premature reannealing. Topoisomerase solves the problem caused by tension generated by winding/unwinding of DNA. This enzyme wraps around DNA and makes a cut permitting the helix to spin and relax. Once DNA is relaxed, topoisomerase reconnects broken strands. DNA primase synthesizes a short RNA primer which initiates the Okazaki fragment. Okazaki fragments are attached by DNA ligase.

Vultures, raccoons and blowflies are examples of what?

consumer

producer

predator

scavengers

Scavengers consume the soft tissues of dead animals. Examples of scavengers include vultures, raccoons, and blowflies.

What holds together adenine and thymine?

helium bonds

covalent bonds

potassium bonds

hydrogen bonds

The base-pairing nature of DNA. Adenine always pairs with thymine, and they are held together with two hydrogen bonds. The guanine-cytosine base pair is held together with three hydrogen bonds. Note that one sugar-phosphate backbone is in the 5’ → 3’ direction, with the other strand in the opposite 3’ → 5’ orientation. Notice that the 5'-end begins with a free (not attached to the sugar of another nucleotide) phosphate group, while the 3'-end has a free (not attached to the phosphate group of another nucleotide) deoxyribose sugar.

Approximately 20% of the atmosphere is made of which element?

nitrogen

hydrogen

carbon

oxygen

Approximately 20% of the atmosphere is oxygen. This gas is essential for life. In environments where oxygen is in low supply, it can be provided from a tank. Since gases are very compressible, a large amount of oxygen can be stored in a relatively small container. When it is released, the volume expands and the pressure decreases. The gas is then available for breathing under normal pressure.

Compound forms when atoms of nonmetals form molecules that are held together by what?

dissonance bonds

phenotype bonds

magnetic bonds

covalent bonds

Compound forms when atoms of nonmetals form molecules that are held together by covalent bonds.

The bony socket that houses the eyeball and associated muscles is called?

acetabulum

cavity

glenoid fossa

orbit

The Orbit The orbit is the bony socket that houses the eyeball and contains the muscles that move the eyeball or open the upper eyelid. Each orbit is cone-shaped, with a narrow posterior region that widens toward the large anterior opening. To help protect the eye, the bony margins of the anterior opening are thickened and somewhat constricted. The medial walls of the two orbits are parallel to each other but each lateral wall diverges away from the midline at a 45° angle. This divergence provides greater lateral peripheral vision. The walls of each orbit include contributions from seven skull bones (Figure 7.16). The frontal bone forms the roof and the zygomatic bone forms the lateral wall and lateral floor. The medial floor is primarily formed by the maxilla, with a small contribution from the palatine bone. The ethmoid bone and lacrimal bone make up much of the medial wall and the sphenoid bone forms the posterior orbit. At the posterior apex of the orbit is the opening of the optic canal, which allows for passage of the optic nerve from the retina to the brain. Lateral to this is the elongated and irregularly shaped superior orbital fissure, which provides passage for the artery that supplies the eyeball, sensory nerves, and the nerves that supply the muscles involved in eye movements.

Humans cannot digest what primary structural material of plants, which is one of the most abundant organic substances on earth?

zinc

sulfur

carbonate

cellulose

Starches (a) and cellulose (b) differ in the connection between glucose units and the amount of branching in the molecule. Starches can be coiled or branched, whereas cellulose, the primary structural material of plants, has long, unbranched chains held together by hydrogen bonds. Cellulose is the primary structural material of plants and one of the most abundant organic substances on Earth. Because our enzymes are not able to hydrolyze the bonds between the glucose units in cellulose, we are unable to digest it. A recently marketed product containing a high percentage of cellulose was sold as a dietetic substance for rapid weight loss, but those who consumed it experienced severe intestinal discomfort because the cellulose could not be digested. The product was quickly removed from the market.

Myofibrils are long cylindrical structures that lie parallel to and run the entire length of what fibers?

heart muscle fibers

uplift muscle fibers

luminous muscle fibers

skeletal muscle fibers

Skeletal Muscle Fiber Structure and Function Each skeletal muscle fiber is a skeletal muscle cell. Within each muscle fiber are myofibrils, long cylindrical structures that lie parallel to the muscle fiber. Myofibrils run the entire length of the muscle fiber. They attach to the plasma membrane, called the sarcolemma, at their ends, so that as myofibrils shorten, the entire muscle cell contracts (Figure 16.18).

The inside of the small intestine has many folds, called villi. microvilli are lined with blood vessels as well as lymphatic vessels. the inside of the small intestine is called this?

osmotic

reticular

porous

lumen

The inside of the small intestine has many folds, called villi. Microvilli are lined with blood vessels as well as lymphatic vessels. The inside of the small intestine is called the lumen. Figure 34.19 Which of the following statements about digestive processes is true? a. Amylase, maltase and lactase in the mouth digest carbohydrates. Trypsin and lipase in the stomach digest protein. Bile emulsifies lipids in the small intestine. No food is absorbed until the small intestine.

What broad animal group is thought to have evolved from theropod dinosaurs around 150 million years ago?

reptiles

insects

mammals

birds

Birds are thought to have evolved from theropod dinosaurs around 150 million years ago. Their ancestor may have been similar to the extinct theropod Deinonychus, whose fossils convinced most scientists that birds evolved from dinosaurs. Scientist still don’t know how or why wings and flight evolved, but they continue to search for answers.

What is the protein in red blood cells which transports oxygen around the body?

hematocrit

plasma

hydrogen

hemoglobin

What do you see when you look at this picture? Is it just a mass of tangled ribbons? Look closely. It’s actually a complex pattern of three-dimensional shapes. It represents the structure of a common chemical found inside living cells. The chemical is a protein called hemoglobin. It is the protein in red blood cells which transports oxygen around the body.

Organs involved in digestion that do not have food pass through them are called?

bypass organs

vestigial organs

layer organs

accessory organs

Other organs involved in digestion include the liver, gall bladder, and pancreas. They are called accessory organs because food does not pass through them. Instead, they secrete or store substances needed for digestion.

At a synapse, what objects are released to carry a nerve impulse from one neuron to the next?

microorganisms

viruses

receptors

neurotransmitters

Laura Guerin. At a synapse, neurotransmitters are released to carry a nerve impulse from one neuron to the next . CC BY-NC 3.0.

All cells have a jellylike substance in which subcellular components are suspended. what is that substance?

cortisol

glycerol

plasma

cytosol

In physics, when one subtracts the frictional force from the applied force what is the result?

kinetic force

rolled force

quarter force

net force

The net force is found by subtracting the frictional force from the applied force.

What is the term for the force that brings objects toward the earth?

centrifugal

weight

light

gravity

Skyscrapers and other large structures built on soft ground must be anchored to what, located below the ground surface?

water table

ocean floor

groundwater

bedrock

Skyscrapers and other large structures built on soft ground must be anchored to bedrock. Sometimes the bedrock lies hundreds of meters below the ground surface.

When your brain senses that your body temperature is increasing, it sends messages to the blood vessels in the skin to increase in what?

weight

surface

height

diameter

The cardiovascular system also plays a role in maintaining body temperature. It helps to keep you warm by moving warm blood around your body. Your blood vessels also control your body temperature to keep you from getting too hot or too cold. When your brain senses that your body temperature is increasing, it sends messages to the blood vessels in the skin to increase in diameter. Increasing the diameter of the blood vessels increases the amount of blood and heat that moves near the skin's surface. The heat is then released from the skin. This helps you cool down. What do you think your blood vessels do when your body temperature is decreasing?.

Which fish has a round sucker used to suck the blood of other fish?

moray

shark

abalone

lamprey

Lampreys Lampreys lack scales but have fins and a partial backbone. Their mouth is surrounded by a large round sucker with teeth. They use the sucker to suck the blood of other fish. lampreys.

What type of change is undergone when the physical properties of a substance are changed?

atmospheric

thermal

genetic

physical

Any time the physical properties of a substance are changed, we can say the substance has undergone a physical change . All substances undergo physical changes where there is a change in the form of the substance but not in its chemical composition. For instance, the grinding of granular sugar into powdered sugar is a physical change. Similarly, dissolving sugar in water is a physical change. We can also use physical changes to separate mixtures into their components. There are a variety of methods used, and the best procedure depends largely on the nature of the mixture. Depending on the states of matter involved, the relative sizes of the mixtures components, and whether the mixture is homogeneous or heterogeneous will determine the necessary separation technique.

Digestive enzymes are released, or secreted, by the organs of which body system?

endocrine system

nervous system

urinary system

digestive system

Digestive enzymes are released, or secreted, by the organs of the digestive system. These enzymes include proteases that digest proteins, and nucleases that digest nucleic acids. Examples of digestive enzymes are:.

When water is aerated it can provide a plant's roots with what gas for cellular respiration?

carbon dioxide

nitrogen

carbon

oxygen

Calcium ion is an example of what kind of messenger?

first

third

fourth

second

Second Messengers Second messengers are small molecules that propagate a signal after it has been initiated by the binding of the signaling molecule to the receptor. These molecules help to spread a signal through the cytoplasm by altering the behavior of certain cellular proteins. Calcium ion is a widely used second messenger. The free concentration of calcium ions (Ca2+) within a cell is very low because ion pumps in the plasma membrane continuously use adenosine-5'-triphosphate (ATP) to remove it. For signaling purposes, Ca2+ is stored in cytoplasmic vesicles, such as the endoplasmic reticulum, or accessed from outside the cell. When signaling occurs, ligand-gated calcium ion channels allow the higher levels of Ca2+ that are present outside the cell (or in intracellular storage compartments) to flow into the cytoplasm, which raises the concentration of cytoplasmic Ca2+. The response to the increase in Ca2+ varies, depending on the cell type involved. For example, in the β-cells of the pancreas, Ca2+ signaling leads to the release of insulin, and in muscle cells, an increase in Ca 2+ leads to muscle contractions. Another second messenger utilized in many different cell types is cyclic AMP (cAMP). Cyclic AMP is synthesized by the enzyme adenylyl cyclase from ATP (Figure 9.12). The main role of cAMP in cells is to bind to and activate an enzyme called cAMP-dependent kinase (A-kinase). A-kinase regulates many vital metabolic pathways: It phosphorylates serine and threonine residues of its target proteins, activating them in the process. A-kinase is found in many different types of cells, and the target proteins in each kind of cell are different. Differences give rise to the variation of the responses to cAMP in different cells.

Aspirin and ibuprofen reduce pain by inhibiting the synthesis of what?

hormones

triglycerides

lipids

prostaglandins

What unit do astronomers use to describe distances in space?

gravity years

quantum years

light months

light years

Astronomers use light years as the unit to describe distances in space. Remember that a light year is the distance light travels in one year.

What is the process by which water moves through semi-permeable membranes from one part of the body to another?

mitosis

diffusion

electrolysis

osmosis

26.1 | Body Fluids and Fluid Compartments By the end of this section, you will be able to: • Explain the importance of water in the body • Contrast the composition of the intracellular fluid with that of the extracellular fluid • Explain the importance of protein channels in the movement of solutes • Identify the causes and symptoms of edema The chemical reactions of life take place in aqueous solutions. The dissolved substances in a solution are called solutes. In the human body, solutes vary in different parts of the body, but may include proteins—including those that transport lipids, carbohydrates, and, very importantly, electrolytes. Often in medicine, a mineral dissociated from a salt that carries an electrical charge (an ion) is called and electrolyte. For instance, sodium ions (Na+) and chloride ions (Cl-) are often referred to as electrolytes. In the body, water moves through semi-permeable membranes of cells and from one compartment of the body to another by a process called osmosis. Osmosis is basically the diffusion of water from regions of higher concentration to regions of lower concentration, along an osmotic gradient across a semi-permeable membrane. As a result, water will move into and out of cells and tissues, depending on the relative concentrations of the water and solutes found there. An appropriate balance of solutes inside and outside of cells must be maintained to ensure normal function.

What cells are the basis of nervous tissue?

osteoclasts

erythrocytes

lipocytes

neurons

Neurons Neurons are the cells considered to be the basis of nervous tissue. They are responsible for the electrical signals that communicate information about sensations, and that produce movements in response to those stimuli, along with inducing thought processes within the brain. An important part of the function of neurons is in their structure, or shape. The threedimensional shape of these cells makes the immense numbers of connections within the nervous system possible.

Pure carbon can exist in different forms, depending on how its atoms are arranged. the forms include diamond, graphite, and what else?

ligands

calcites

lead

fullerenes

Pure carbon can exist in different forms, depending on how its atoms are arranged. The forms include diamond, graphite, and fullerenes. All three forms exist as crystals, but they have different structures. Their different structures, in turn, give them different properties. You can learn more about them in Table below .

Which cavity, filled with lubricating serous fluid, lies between the epicardium and the pericardium?

thoracic cavity

cranial cavity

oral cavity

pericardial cavity

and is part of the heart wall. The pericardial cavity, filled with lubricating serous fluid, lies between the epicardium and the pericardium. In most organs within the body, visceral serous membranes such as the epicardium are microscopic. However, in the case of the heart, it is not a microscopic layer but rather a macroscopic layer, consisting of a simple squamous epithelium called a mesothelium, reinforced with loose, irregular, or areolar connective tissue that attaches to the pericardium. This mesothelium secretes the lubricating serous fluid that fills the pericardial cavity and reduces friction as the heart contracts. Figure 19.5 illustrates the pericardial membrane and the layers of the heart.

Layers of what create a volcano?

crust

rock

limestone

lava

Magma beneath a volcano erupts onto the volcano’s surface. Layer upon layer of lava creates a volcano.

In amphibians, reptiles, birds, and mammals, blood flow is directed in two circuits: one through the lungs and back to the heart, which is called what?

metabolic circulation

systemic circulation

sensory circulation

pulmonary circulation

In amphibians, reptiles, birds, and mammals, blood flow is directed in two circuits: one through the lungs and back to the heart, which is called pulmonary circulation, and the other throughout the rest of the body and its organs including the brain (systemic circulation). In amphibians, gas exchange also occurs through the skin during pulmonary circulation and is referred to as pulmocutaneous circulation. As shown in Figure 40.4b, amphibians have a three-chambered heart that has two atria and one ventricle rather than the two-chambered heart of fish. The two atria (superior heart chambers) receive blood from the two different circuits (the lungs and the systems), and then there is some mixing of the blood in the heart’s ventricle (inferior heart chamber), which reduces the efficiency of oxygenation. The advantage to this arrangement is that high pressure in the vessels pushes blood to the lungs and body. The mixing is mitigated by a ridge within the ventricle that diverts oxygen-rich blood through the systemic circulatory system and deoxygenated blood to the pulmocutaneous circuit. For this reason, amphibians are often described as having double circulation. Most reptiles also have a three-chambered heart similar to the amphibian heart that directs blood to the pulmonary and systemic circuits, as shown in Figure 40.4c. The ventricle is divided more effectively by a partial septum, which results in less mixing of oxygenated and deoxygenated blood. Some reptiles (alligators and crocodiles) are the most primitive animals to exhibit a four-chambered heart. Crocodilians have a unique circulatory mechanism where the heart shunts blood from the lungs toward the stomach and other organs during long periods of submergence, for instance, while the animal waits for prey or stays underwater waiting for prey to rot. One adaptation includes two main arteries that leave the same part of the heart: one takes blood to the lungs and the other provides an alternate route to the stomach and other parts of the body. Two other adaptations include a hole in the heart between the two ventricles, called the foramen of Panizza, which allows blood to move from one side of the heart to the other, and specialized connective tissue that slows the blood flow to the lungs. Together these adaptations have made crocodiles and alligators one of the most evolutionarily successful animal groups on earth. In mammals and birds, the heart is also divided into four chambers: two atria and two ventricles, as illustrated in Figure 40.4d. The oxygenated blood is separated from the deoxygenated blood, which improves the efficiency of double circulation and is probably required for the warm-blooded lifestyle of mammals and birds. The four-chambered heart of birds and mammals evolved independently from a three-chambered heart. The independent evolution of the same or a similar biological trait is referred to as convergent evolution.

Non-human organisms that mainly consume plants/other primary producers are known as what?

omnivores

amphibians

carnivores

herbivores

In the microbiology lab, what technique refers to the procedures that are carried out under sterile conditions?

ionization

personal hygiene

experimental control

aseptic

In the microbiology lab, aseptic technique refers to the procedures that are carried out under sterile conditions. Scientists who study microbes are called microbiologists. Microbiologists must carry out their lab work using the aseptic technique to prevent microbial contamination of themselves, contamination of the environment they are working in, including work surfaces or equipment, and contamination of the sample they are working on. Bacteria live on just about every surface on Earth, so if a scientist wants to grow a particular type of bacterium in the lab, he or she needs to be able to sterilize their equipment to prevent contamination by other bacteria or microorganisms. The aseptic technique is also used in medicine, where it is important to keep the human body free of contamination.

Connecting a magnesium rod to an underground steel pipeline protects the pipeline from corrosion. because magnesium (e° = −2.37 v) is much more easily oxidized than iron (e° = −0.45 v), the mg rod acts as the anode in a what?

voltaic cell

anode cell

stimulation cell

galvanic cell

Connecting a magnesium rod to an underground steel pipeline protects the pipeline from corrosion. Because magnesium (E° = −2.37 V) is much more easily oxidized than iron (E° = −0.45 V), the Mg rod acts as the anode in a galvanic cell. The pipeline is therefore forced to act as the cathode at which oxygen is reduced. The soil between the anode and the cathode acts as a salt bridge that completes the electrical circuit and maintains electrical neutrality. As Mg(s) is oxidized to Mg2+ at the anode, anions in the soil, such as nitrate, diffuse toward the anode to neutralize the positive charge. Simultaneously, cations in the soil, such as H+ or NH4+, diffuse toward the cathode, where they replenish the protons that are consumed as oxygen is reduced. A similar strategy uses many miles of somewhat less reactive zinc wire to protect the Alaska oil pipeline.

Matrix is the term for the fluid-filled interior of what structure, where most of the cell’s atp is made?

enzyme

nucleus

Golgi apparatus

mitochondria

As the Figure below (a) and (b) shows, a mitochondrion has two phospholipids membranes. The smooth outer membrane separates the mitochondrion from the cytosol. The inner membrane has many folds, called cristae . These cristae greatly increase the membrane surface area for integral proteins. Many proteins involved in cellular respiration are embedded in this inner membrane. The greater surface area allows more proteins to be located there, resulting in more cellular respiration reactions, and more ATP synthesis. ATP is produced by the enzyme ATP synthase, which is a membrane protein of the mitochondria inner membrane. The fluid-filled inside of the mitochondrian, called matrix , is where most of the cell’s ATP is made.