Biology Questions
Chapter 6: Cell Energy, Transport and Enzymes
1) Many of the enzymes that control a deep-sea firefly squid's ability to produce light energy from chemical energy are located A) in membranes. B) in the nucleus. C) within chloroplasts. D) outside of cells. E) within mitochondria. 2) The fluid mosaic model describes the plasma membrane as consisting of A) a phospholipid bilayer with embedded carbohydrates. B) two layers of phospholipids with protein sandwiched between them. C) a protein bilayer with embedded phospholipids. D) carbohydrates, proteins, and phospholipids that can drift in the membrane. E) individual proteins and phospholipids that can drift in a phospholipid bilayer. 3) Membrane phospholipids A) have hydrophobic heads that face the center of the membrane and are shielded from water. B) have hydrophilic tails that face outward and are exposed to water. C) often have "kinks" in their tails caused by the presence of a double bond between carbons. D) remain fluid because they are tightly packed against one another. E) form impermeable layers for cells. 4) The cholesterol associated with animal cell membranes A) is attached to membrane proteins and extends into the watery environment surrounding the cell. B) helps to stabilize the cell membrane at body temperature. C) makes the cell membrane fluid at room temperature. D) is an abnormality resulting from a diet high in cholesterol. E) helps solidify the membranes when the room temperature is below freezing. 5) A major function of glycoproteins and glycolipids in the cell membrane is to A) glue cells together to form tissues. B) allow the cells of an embryo to sort themselves into tissues and organs. C) attach the cell membrane to the cytoskeleton. D) help the cell resist swelling. E) help the cell retain its shape. 6) When physicians perform an organ transplant, they choose a donor whose tissues match those of the recipient as closely as possible. Which of the following cell components are being matched? A) plasma membrane phospholipids B) plasma membrane proteins C) cell-surface carbohydrates D) plasma membrane cholesterols E) cytoskeletal elements 7) Most of the functions of a cell membrane are performed by A) glycolipids. B) proteins. C) phospholipids. D) cholesterol. E) nucleotides.
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9) Relaying a message from a membrane receptor to a molecule that performs a specific function within a cell is called A) signal transduction. B) inhibition. C) competition. D) self-recognition. E) selective permeability. 10) Plasma membranes are selectively permeable. This means that A) anything can pass into or out of a cell as long as the membrane is intact and the cell is healthy. B) the plasma membrane allows some substances to enter or leave a cell more easily than others. C) glucose cannot enter the cell. D) cholesterol cannot enter the cell. E) plasma membranes must be very thick. 12) Small, nonpolar, hydrophobic molecules such as fatty acids A) easily pass through a membrane's lipid bilayer. B) very slowly diffuse through a membrane's lipid bilayer. C) require transport proteins to pass through a membrane's lipid bilayer. D) are actively transported across cell membranes. E) usually enter the cell via endocytosis. 13) Which characteristic promoted the utilization of lipids as the first cell membrane? A) spontaneous degradation of the intracellular environment B) self-assembly into a simple membrane C) ability to form an impermeable membrane D) formation of a semi-solid membrane E) utilization of the hydrophilic nature of lipids 14) All cells are enclosed by a plasma membrane that is similar in ________ and ________. A) thickness . . . composition B) permeability . . . content C) proteins . . . lipids D) lucidity . . . texture E) structure . . . function 15) Which of the following substances would have the most trouble crossing a biological membrane by diffusing through the lipid bilayer? A) H2O B) O2 C) CO2 D) Na+ E) a small, nonpolar molecule such as butane (C4H10) 16) Oxygen crosses a plasma membrane by A) osmosis. B) phagocytosis. C) active transport. D) pinocytosis. E) passive transport. 17) Which of the following statements regarding diffusion is false? A) Diffusion is a result of the kinetic energy of atoms and molecules. B) Diffusion is driven by concentration gradients.
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C) Diffusion requires no input of energy into the system. D) Diffusion occurs when particles spread from areas where they are less concentrated to areas where they are more concentrated. E) Diffusion occurs even after equilibrium is reached and no net change is apparent. 18) Diffusion does not require the cell to expend ATP. Therefore, diffusion is considered a type of A) exocytosis. B) phagocytosis. C) passive transport. D) active transport. E) endocytosis. 19) Osmosis can be defined as A) the diffusion of water. B) the diffusion of nonpolar molecules. C) active transport. D) the diffusion of a solute. E) endocytosis. 20) When two aqueous solutions that differ in solute concentration are placed on either side of a semipermeable membrane and osmosis is allowed to take place, the water will A) exhibit a net movement to the side with lower water concentration. B) exhibit a net movement to the side with higher water concentration. C) exhibit a net movement to the side with lower solute concentration. D) exhibit an equal movement in both directions across the membrane. E) not cross the membrane. 22) Some protozoans have special organelles called contractile vacuoles that continually eliminate excess water from the cell. The presence of these organelles tells you that the environment A) is isotonic to the protozoan. B) is hypotonic to the protozoan. C) is contaminated with pollutants. D) contains a higher concentration of solutes than the protozoan. E) is hypertonic to the protozoan. 23) A cell that neither gains nor loses water when it is immersed in a solution is A) isotonic to its environment. B) hypertonic to its environment. C) hypotonic to its environment. D) metabolically inactive. E) dead. 24) In a hypotonic solution, an animal cell will A) lyse. B) experience turgor. C) neither gain nor lose water. D) shrivel. E) lose water. 26) In the lab, you use a special balloon that is permeable to water but not sucrose to make an "artificial cell." The balloon is filled with a solution of 20% sucrose and 80% water and is immersed in a beaker containing a solution of 40% sucrose and 60% water. The solution in the balloon is ________ relative to the solution in the beaker. A) isotonic B) hypotonic C) hypertonic
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D) hydrophobic E) hydrophilic 28) A plant cell in a hypotonic solution A) is turgid. B) lyses. C) shrivels. D) wilts. E) is flaccid. 30) Facilitated diffusion across a biological membrane requires ________ and moves a substance ________ its concentration gradient. A) energy and transport proteins . . . down B) energy . . . down C) transport proteins . . . down D) energy and transport proteins . . . against E) transport proteins . . . against 31) The molecules responsible for membrane transport are A) steroids. B) ATP. C) phospholipids. D) carbohydrates. E) proteins. 33) Which of the following processes can move a solute against its concentration gradient? A) osmosis B) passive transport C) diffusion D) facilitated diffusion E) active transport 34) Which of the following processes could result in the net movement of a substance into a cell, if the substance is more concentrated in the cell than in the surroundings? A) active transport B) facilitated diffusion C) diffusion D) osmosis E) passive transport. 35) Which of the following is a typical feature of an ATP-driven active transport mechanism? A) The transport protein must cross to the correct side of the membrane before the solute can bind to it. B) The solute must be phosphorylated before it can bind to the transport protein. C) The transport protein is irreversibly phosphorylated as transport takes place. D) The transport protein catalyzes the conversion of ADP to ATP. E) The solute moves against the concentration gradient. 37) Certain cells that line the stomach synthesize a digestive enzyme and secrete it into the stomach. This enzyme is a protein. Which of the following processes could be responsible for its secretion? A) endocytosis B) exocytosis C) diffusion D) pinocytosis E) passive transport
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38) The process of a white blood cell engulfing a bacterium is A) osmosis. B) diffusion. C) receptor-mediated endocytosis. D) pinocytosis. E) phagocytosis. 39) Phagocytosis is to eating as pinocytosis is to A) osmosis. B) drinking. C) chewing. D) hydrolysis. E) lysis. 40) Cells acquire LDLs by A) osmosis. B) diffusion. C) receptor-mediated endocytosis. D) pinocytosis. E) phagocytosis. 41) Kinetic energy differs from chemical energy in that A) kinetic energy is stored energy that has the potential to do work, and chemical energy is the energy of movement. B) kinetic energy depends on the movement of atoms, whereas chemical energy depends on the movement of molecules. C) kinetic energy can be converted into various forms of energy, whereas chemical energy can only be converted into heat. D) kinetic energy is the energy of a moving object, whereas chemical energy is the potential energy of molecules. E) chemical energy is a particular form of kinetic energy. 42) Glucose molecules provide energy to power the swimming motion of sperm. In this example, the sperm are changing A) chemical energy into kinetic energy. B) chemical energy into potential energy. C) kinetic energy into potential energy. D) kinetic energy into chemical energy. E) kinetic energy into thermal energy. 43) In the reaction A → B + C + heat, A) there is a net input of energy. B) the potential energy of the products is greater than that of the reactant. C) the potential energy of the products is the same as that of the reactant. D) the potential energy of the products is less than that of the reactant. E) entropy has decreased. 45) According to ________, energy cannot be created or destroyed. A) Aristotle's first principle B) the first law of thermodynamics C) the second law of thermodynamics D) the third law of thermodynamics E) Einstein's law of relativity 47) Which of the following energy transfers is impossible in living systems? A) light energy to chemical energy B) chemical energy to kinetic energy C) potential energy to kinetic energy D) light energy to potential energy
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E) heat to light energy. 48) Living systems A) violate the first law of thermodynamics. B) violate the second law of thermodynamics. C) decrease their entropy while increasing the entropy of the universe. D) are examples of a closed system. E) are only compelled to follow the first law of thermodynamics. 49) Which of the following processes is endergonic? A) the burning of wood B) the release of heat from the breakdown of glucose C) the synthesis of glucose from carbon dioxide and water D) the breakdown of glucose E) cellular respiration 50) What is the basic difference between exergonic and endergonic reactions? A) Exergonic reactions involve ionic bonds; endergonic reactions involve covalent bonds. B) Exergonic reactions involve the breaking of bonds; endergonic reactions involve the formation of bonds. C) Exergonic reactions involve the formation of bonds; endergonic reactions involve the breaking of bonds. D) Exergonic reactions release energy; endergonic reactions absorb it. E) In exergonic reactions, the reactants have less chemical energy than the products; in endergonic reactions, the opposite is true. 52) Which of the following examples is classified as a metabolic pathway? A) protein synthesis B) osmosis C) cell lysis D) spontaneous combustions E) passive diffusion 53) When a cell uses chemical energy to perform work, it couples a(n) ________ reaction with a(n) ________ reaction. A) exergonic . . . endergonic B) endergonic . . . exergonic C) exergonic . . . spontaneous D) spontaneous . . . exergonic E) endergonic . . . spontaneous 55) The transfer of a phosphate group to a molecule or compound is called A) carboxylation. B) ionization. C) phosphorylation. D) hydrogen bonding. E) hydrogenation. 56) Anything that prevents ATP formation will most likely A) result in cell death. B) force the cell to rely on lipids for energy. C) result in the conversion of kinetic energy to potential energy. D) force the cell to rely on ADP for energy. E) have no effect on the cell. 57) ATP can be used as the cell's energy exchange mechanism because A) endergonic reactions can be fueled by coupling them with the formation of ATP from ADP. B) ATP is the most energy-rich small molecule in the cell. C) endergonic reactions can be fueled by coupling them with the hydrolysis of high-energy phosphate bonds in ATP.
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D) the regeneration of ATP from ADP can be fueled by coupling it with endergonic reactions. E) ATP is a disposable form of chemical energy, used once and then discarded by the cell. 58) An energy barrier A) is the amount of energy that must be produced by the reactants to start a chemical reaction. B) is higher than the energy of activation of a reaction. C) is lower than the energy of activation of a reaction. D) prevents the spontaneous decomposition of molecules in the cell. E) can only be overcome with the use of enzymes. 59) The energy required to initiate an exergonic reaction is called A) exergonic energy. B) endergonic energy. C) input energy. D) hydrolytic energy. E) the energy of activation. 60) Most of a cell's enzymes are A) lipids. B) proteins. C) amino acids. D) nucleic acids. E) carbohydrates. 61) When an enzyme catalyzes a reaction, A) it lowers the activation energy of the reaction. B) it raises the activation energy of the reaction. C) it becomes a product. D) it acts as a reactant. E) it is used once and discarded. 62) Substrates bind to an enzyme's ________ site. A) reactant B) allosteric C) regulatory D) phosphate E) active 63) The active site of an enzyme is A) the region of a substrate that is changed by an enzyme. B) the highly changeable portion of an enzyme that adapts to fit the substrates of various reactions. C) the region of an enzyme that attaches to a substrate. D) the region of a product that detaches from the enzyme. E) the region of the enzyme composed of only a few specific nucleic acids. 67) Heating inactivates enzymes by A) breaking the covalent bonds that hold the molecule together. B) removing phosphate groups from the enzyme. C) causing enzyme molecules to stick together. D) changing the enzyme's three-dimensional shape. E) inducing the addition of amino acids. 68) Which of the following substances could be a cofactor? A) a protein B) a polypeptide
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C) a zinc atom D) a ribosome E) collagen 69) Which of the following is a coenzyme? A) zinc B) vitamin B6 C) iron D) iodine E) hydrogen ions 70) Which of the following will have no effect on the rate of an enzyme-catalyzed reaction? A) temperature B) pH C) competitive inhibitors D) noncompetitive inhibitors E) net change in energy 71) Inhibition of an enzyme is irreversible when A) a competitive inhibitor is involved. B) a noncompetitive inhibitor is involved. C) the shape of the enzyme is changed. D) covalent bonds form between inhibitor and enzyme. E) weak interactions form between inhibitor and enzyme.
BSC 1005 Chapter 7 Cellular Respiration and Fermentation
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Chapter 7 Cellular Respiration and Fermentation 1) Substrate-level phosphorylation occurs _____.
A) in glycolysis B) in the citric acid cycle C) in both glycolysis and the citric acid cycle D) during oxidative phosphorylation
2) When electrons move closer to a more electronegative atom, what happens? The more electronegative atom
is _____. A) reduced, and energy is released B) reduced, and energy is consumed C) oxidized, and energy is consumed D) oxidized, and energy is released
3) When a glucose molecule loses a hydrogen atom as the result of an oxidation-reduction reaction, the
molecule becomes _____. A) hydrolyzed B) oxidized C) reduced D) an oxidizing agent
4) Which of the following statements about NAD+ is true?
A) NAD+ is reduced to NADH during glycolysis, pyruvate oxidation, and the citric acid cycle. B) NAD+ has more chemical energy than NADH. C) NAD+ can donate electrons for use in oxidative phosphorylation. D) In the absence of NAD+, glycolysis can still function.
5) The oxygen consumed during cellular respiration is involved directly in which process or event?
A) glycolysis B) accepting electrons at the end of the electron transport chain C) the citric acid cycle D) the oxidation of pyruvate to acetyl CoA
6) During which of the following steps is no ATP made–
A) Glycolysis B) Electron transport chain C) Pyruvate oxidation D) Krebs cycle E) ATP is made during all the steps
7) Starting with one molecule of glucose, the energy-containing products of glycolysis are _____.
A) 2 NAD+, 2 pyruvate, and 2 ATP B) 2 NADH, 2 pyruvate, and 2 ATP C) 2 FADH2, 2 pyruvate, and 4 ATP D) 6 CO2, 2 pyruvate, and 2 ATP
8) In glycolysis, for each molecule of glucose oxidized to pyruvate _____.
A) two molecules of ATP are used and two molecules of ATP are produced. B) two molecules of ATP are used and four molecules of ATP are produced. C) four molecules of ATP are used and two molecules of ATP are produced.
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D) two molecules of ATP are used and six molecules of ATP are produced. 9) Following glycolysis and the citric acid cycle, but before the electron transport chain and oxidative
phosphorylation, the carbon skeleton of glucose has been broken down to CO2 with some net gain of ATP. Most of the energy from the original glucose molecule at that point in the process, however, is in the form of _____.
A) acetyl-CoA B) glucose C) pyruvate D) NADH
10) The 2 carbons in acetyl–CoA are eventually used to form —
A) Glucose B) ATP C) Pyruvate D) Oxaloacetate E) Carbon dioxide
11) Which electron carrier(s) function in the citric acid cycle?
A) NAD+ only B) NADH and FADH2 C) the electron transport chain D) ADP and ATP
12) All of the glycolysis reactions do not require oxygen and can take place in an anaerobic environment.
A) This is true B) This is false
13) What is the function of the coenzymes, NADH and FADH2 ?
A) Charging electrons to power ATP synthase B) Catalyzing the formation of acetyl-CoA C) Providing electrons and H+ to the electron transport chain D) Transporting CO2 into the mitochondria E) Acting as a terminal electron acceptor
14) The electron transport chain _____.
A) is a series of redox reactions B) is a series of substitution reactions C) is driven by ATP consumption D) takes place in the cytoplasm of prokaryotic cells
15) The chemiosmotic hypothesis is an important concept in our understanding of cellular metabolism in general
because it explains _____. A) how ATP is synthesized by a proton motive force B) how electron transport can fuel substrate-level phosphorylation C) the sequence of the electron transport chain molecules D) the reduction of oxygen to water in the final steps of oxidative metabolism
16) ATP synthase –
A) Is an H+ channel B) Is embedded in the cristae C) Spins due to the flow of H+ D) Uses rotational energy to form ATP
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E) All of the above 17) How does substrate level phosphorylation differ from oxidative phosphorylation ?
A) Oxidative makes ADP B) Substrate level requires oxygen C) Oxidative occurs during glycolysis only D) Substrate level uses PO4 from a donor molecule only E) All of the above are correct
18) Where are the proteins of the electron transport chain located?
A) mitochondrial outer membrane B) mitochondrial inner membrane C) mitochondrial intermembrane space D) mitochondrial matrix
19) Energy released by the electron transport chain is used to pump H+ into which location in eukaryotic cells?
A) mitochondrial outer membrane B) mitochondrial inner membrane C) mitochondrial intermembrane space D) mitochondrial matrix
20) When hydrogen ions are pumped from the mitochondrial matrix across the inner membrane and into the
intermembrane space, the result is the _____. A) formation of ATP B) reduction of NAD+ C) creation of a proton-motive force D) lowering of pH in the mitochondrial matrix
21) Approximately how many molecules of ATP are produced from the complete oxidation of one molecule of
glucose (C6H12O6) in aerobic cellular respiration? A) 2 B) 4 C) 18-24 D) 30-32
22) Chemiosmotic ATP synthesis (oxidative phosphorylation) occurs in _____.
A) all cells, but only in the presence of oxygen B) only eukaryotic cells, in the presence of oxygen C) only in mitochondria, using either oxygen or other electron acceptors D) all respiring cells, both prokaryotic and eukaryotic, using either oxygen or other electron
acceptors 23) Alcohol fermentation is an anaerobic process?
A) This is true B) This is false
24) Which of the following occurs in the cytosol of a eukaryotic cell?
A) glycolysis and fermentation B) fermentation and chemiosmosis C) oxidation of pyruvate to acetyl CoA D) citric acid cycle
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25) In the absence of oxygen, yeast cells can obtain energy by fermentation, resulting in the production of _____. A) ATP, CO2, and ethanol (ethyl alcohol) B) ATP, CO2, and lactate C) ATP, NADH, and pyruvate D) ATP, pyruvate, and acetyl CoA
26) What do NADH dehydrogenase and cytochrome oxidase have in common?
A) Both pump H+ from the matrix B) Both are powered by electrons C) Both are embedded in the cristae D) Both are transmembrane proteins E) All of the above
27) One function of both alcohol fermentation and lactic acid fermentation is to _____.
A) reduce NAD+ to NADH B) reduce FAD+ to FADH2 C) oxidize NADH to NAD+ D) reduce FADH2 to FAD+
28) An organism is discovered that thrives in both the presence and absence of oxygen in the air. Curiously, the
consumption of sugar increases as oxygen is removed from the organism's environment, even though the organism does not gain much weight. This organism _____.
A) is a normal eukaryotic organism B) is photosynthetic C) is an anaerobic organism D) is a facultative anaerobe
29) Cyanide inhibits cytochrome oxidase. Why is this lethal?
A) NAD+ can no longer be reduced to NADH B) Electron transport chain is shut down C) Glycolysis is inhibited D) Krebs cycle cannot be initiated E) Pyruvate is not converted to Acetyl-CoA
30) Cyanide inhibits cytochrome oxidase. Why is this lethal?
A) NAD+ can no longer be reduced to NADH B) Electron transport chain is shut down C) Glycolysis is inhibited D) Krebs cycle cannot be initiated E) Pyruvate is not converted to Acetyl-CoA
31) During a heart attack blood flow to the cardiac muscle is restricted. How would this effect cellular respiration?
A) ATP production would be increased B) ATP production would remain unchanged C) ATP production would be decreased D) The cell would switch to alcohol fermentation
32) In E. coli an enzyme, nitrate reductase, is found in the electron transport chain. The enzyme transfers an
electron to nitrate (NO3) instead of oxygen. What type of pathway is this? A) Aerobic respiration B) Anaerobic respiration
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C) Fermentation
BSC1005 Biology General Chapter 8 Photosynthesis
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Chapter 8 Photosynthesis
1) The summary equation for photosynthesis is A) 6 CO2 + 6 H2O + sunlight → C6H12O6 + 6 O2. B) C5H12O6 + 6 O2 + sunlight → 5 CO2 + 6 H2O. C) C6H12O6 + 6 O2 + sunlight → 6 CO2 + 6 H2O. D) the same as the equation for glycolysis written in reverse. E) 6 CH2O + 5 O2 + sunlight → CO2 + 2 H2O. 2) Which of the following statements regarding photosynthesis and carbon dioxide is false? A) Plants require carbon dioxide, water, and sunlight to make glucose. B) Burning fossil fuels release carbon dioxide that was removed from the atmosphere millions of years ago, C) Because of their short growth period and self-regeneration, willows are more viable as a source of potential power than the trees in most natural forests. D) Most of the food humans eat can be traced back to photosynthetic plants. E) Burning wood contributes more to acid rain than burning fossil fuels. 3) What is the name given to organisms that can make their own food and the food for the biosphere? A) chemotrophs B) heterotrophs C) manufacturers D) synthesizers E) producers 4) Photoautotrophs A) make sugar by using organic raw materials. B) produce organic molecules from inorganic molecules. C) eat other organisms that use light energy to make food molecules. D) include only the green plants. E) are only found on land. 5) Which of the following is an example of a photoautotroph? A) cyanobacteria in freshwater and marine ecosystems B) grizzly bears in Alaska C) bacteria in our mouth D) fungi growing in the refrigerator E) mushrooms growing on the side of a dead tree 6) Autotrophs that utilize light as their energy source are A) chemosynthetic autotrophs. B) photoautotrophs. C) consumers. D) fungi. E) heterotrophs. 7) What is the likely origin of chloroplasts? A) mitochondria that had a mutation for photosynthesis B) photosynthetic prokaryotes that lived inside eukaryotic cells C) a combination of mitochondria and Golgi bodies D) prokaryotes with photosynthetic mitochondria E) eukaryotes that engulfed photosynthetic fungi 8) In most green plants, chloroplasts are A) concentrated in a zone of leaf tissue called the mesophyll.
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B) concentrated in the stomata. C) concentrated in a portion of the leaf called the stroma. D) found throughout the leaf tissue. E) found throughout the plant. 9) ________ cells in leaves are specialized for photosynthesis. A) Companion B) Mesophyll C) Sclerenchyma D) Tracheid E) Collenchyma 10) CO2 enters and O2 escapes from a leaf via A) stomata. B) thylakoids. C) grana. D) stroma. E) central vacuoles. 11) In the chloroplast, sugars are made in a compartment that is filled with a thick fluid called the A) stomata. B) thylakoid. C) matrix. D) stroma. E) mesophyll. 12) Chloroplasts contain disklike membranous sacs arranged in stacks called A) cristae. B) thylakoids. C) grana. D) vacuoles. E) stroma. 13) Where is chlorophyll found in a plant cell? A) stroma B) thylakoid membranes C) matrix D) cytoplasm E) cristae 14) The oxygen released into the air as a product of photosynthesis comes from A) water. B) glucose. C) carbon dioxide. D) chlorophyll. E) mitochondria. 15) Which of the following molecules is both a reactant and a product of photosynthesis? A) H2O B) glucose C) O2 D) CO2 E) chlorophyll
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16) If you expose a photosynthesizing plant to water that contains both radioactive H and radioactive O, in which of the products of photosynthesis will the radioactive H and O show up? A) H and O both in glucose B) H in glucose; O in water C) H in water; O in glucose D) H in glucose and water; O in O2 E) H in glucose and water; O in water and O2 17) A redox reaction involves the transfer of A) a hydrogen ion. B) oxygen. C) water. D) an electron. E) carbon dioxide. 18) Which of the following statements concerning the role of redox reactions in photosynthesis and cellular respiration is true? A) Photosynthesis involves only reductions, while respiration involves only oxidations. B) Photosynthesis involves only oxidations, while respiration involves only reductions. C) In photosynthesis, carbon dioxide is oxidized to form sugar, while in respiration, sugar is reduced to form carbon dioxide. D) In photosynthesis, carbon dioxide is reduced to form sugar, while in respiration, sugar is oxidized to form carbon dioxide. E) Photosynthesis involves both reduction and oxidation, while respiration involves only oxidation. 19) What is the source of energy that provides the boost for electrons during photosynthesis? A) light B) electromagnetism C) cellular respiration D) ATP