Deck 6: Photosynthesis and Cellular Respiration

Question 1

Stomata admit CO₂ to the leaf interior but also facilitate the loss of water from the leaves;plants must regulate their stomata carefully or risk dehydration.A reasonable hypothesis associated with the global increase in atmospheric CO₂ is that plants will

A) evolve lower stomatal densities to reduce the potential for desiccation.
B) grow smaller and more slowly than they do now.
C) keep their stomata closed most of the time to minimize carbon dioxide poisoning.
D) increase their stomatal densities to take advantage of the abundance of CO₂.

Answer 1

A

Question 2

NADH serves as an energy carrier in living organisms by coupling ________ with ________.

A) oxygen production;the generation of carbon dioxide during cellular respiration
B) the synthesis of ATP;the synthesis of water
C) photosynthesis;metabolism
D) the catabolic aspects of cellular respiration;the synthesis of ATP

Answer 2

D

Question 3

If plants are able to capture energy from the sun,why do they need to pass that energy through the chemical reactions that are necessary to produce ATP?

A) ATP enables the energy to be stored for later use or transferred to other chemical reactions.
B) Chloroplasts are unable to use the energy they capture from the sun.
C) Producing ATP enables the plant to destroy excess energy that was captured from the sun.
D) The mitochondria that capture the sun's energy are unable to use it for respiration.

Answer 3

A

Question 4

Which of the following statements describes the function of the electron transport chain (ETC)in photosynthesis?

A) As electrons move through the ETC,they release energy that is used to concentrate protons in the thylakoid lumen.
B) As electrons move through the ETC,they catalyze the formation of ATP.
C) The ETC releases CO₂ from glucose.
D) The ETC captures and stores the electrons that are given off by NADPH.

Question 5

Cells use a variety of metabolic pathways to construct ATP,but each pathway concludes with the same step.Which of the following processes is the final step by which ADP becomes ATP?

A) photosynthesis
B) phosphorylation
C) carbon fixation
D) electron transfer

Question 6

The three stages of aerobic catabolism are

A) photosynthesis,glycolysis,and oxidative phosphorylation.
B) glycolysis,the Krebs cycle,and oxidative phosphorylation.
C) glycolysis,fermentation,and the Krebs cycle.
D) photosynthesis,the Krebs cycle,and fermentation.

Question 7

What is the importance of photosynthesis to organisms other than plants?

A) All other organisms require oxygen for life processes.
B) The sugars made during photosynthesis are building blocks of DNA.
C) All cells must have chloroplasts to survive.
D) Photosynthesis captures energy that other organisms access when they eat either plants or organisms that eat plants.

Question 8

Which of the following statements comparing photosynthesis with cellular respiration is true?

A) Photosynthesis is a catabolic pathway,whereas cellular respiration is an anabolic pathway.
B) Water is formed during photosynthesis but broken apart during cellular respiration.
C) Both photosynthesis and cellular respiration require electron transport chains.
D) Both photosynthesis and cellular respiration produce CO₂ as metabolic end products.

Question 9

Biologists believe that Earth's early life-forms were exposed to an atmosphere that had no molecular oxygen and therefore had not yet evolved the Krebs cycle.If so,alcoholic fermentation would have been particularly critical to life,because without this pathway

A) ethanol would not be available as a nutrient for other consumers.
B) lactic acid would accumulate and disable prokaryotic muscle cells.
C) carbon could not be recycled back into the biosphere for use by producers.
D) the only source of NADH for electron transport would be from glycolysis;therefore,ATP production would be greatly reduced.

Question 10

What is the role of water in photosynthesis?

A) It provides a phosphate group to ATP.
B) It captures light energy and transfers it to the electron transport chain.
C) It provides replacement electrons to the reaction center chlorophyll in photosystem II.
D) It combines with carbon dioxide (CO₂)to make glucose.

Question 11

Which of the following molecules carries electrons that will be used to reduce other molecules in an electron transport chain?

A) ATP
B) NADH
C) CO₂
D) ADP

Question 12

In which of the following functions does ATP NOT participate?

A) synthesis of macromolecules
B) synthesis of water from hydrogen and oxygen
C) membrane transport
D) cytoskeletal organization

Question 13

Today,the pathways of photosynthesis and cellular respiration are complementary and relatively balanced,but early in the history of life on Earth,photosynthesis appears to have dominated.One piece of evidence that suggests the early dominance of photosynthesis is the

A) accumulation of atmospheric oxygen.
B) declines in historic sea levels as photosynthetic organisms consumed water.
C) gradual warming of Earth's climate as CO₂ slowly accumulated.
D) sequestration of O₂ in Earth's oceans.

Question 14

Each time we take a breath,we are bringing in the oxygen we need to stay alive.The ultimate source of the oxygen used by all aerobic organisms comes from a reaction that

A) degrades carbon dioxide.
B) hydrolyzes ATP.
C) splits water.
D) reduces NADPH.

Question 15

The energy carriers NADPH and NADH are different from each other structurally.Functionally,they are

A) quite similar;they both transport electrons and hydrogen ions that are released in catabolic pathways.
B) quite similar;they both transport electrons and hydrogen ions to anabolic pathways.
C) somewhat different;NADPH receives electrons and hydrogen from catabolic processes,whereas NADH delivers those items to anabolic processes.
D) somewhat different;NADH receives electrons and hydrogen from catabolic processes,whereas NADPH delivers those items to anabolic processes.

Question 16

Biologists believe that in the earliest version of photosynthesis,the energized photosystem electron simply cycled back to the chlorophyll molecule.Which of the following limitations would NOT be imposed by such a system?

A) No molecular oxygen would be generated.
B) No electrons would be available to reduce the carbon in CO₂.
C) Cells could produce ATP but not sugars.
D) Cells could produce O₂ but not sugars.

Question 17

Which of the following characteristics applies to chloroplasts?

A) They have an intermembrane space and a matrix.
B) They have three membrane-enclosed compartments.
C) Unlike mitochondria,they lack a stroma.
D) They carry out both photosynthesis and respiration.

Question 18

During the process of photosynthesis,plants capture the kinetic energy of moving photons and transform it into potential energy in the form of

A) pyruvate.
B) stroma.
C) chemical bonds.
D) thylakoid disks.

Question 19

The energetics of photosynthesis often overshadows the importance of carbon fixation;without the vital process of carbon fixation,what would happen?

A) Carbon dioxide levels would decrease uncontrollably,making the Earth too warm to support life.
B) Atmospheric oxygen levels would be too low to support life on Earth.
C) Carbon atoms would still be readily available in biologically useful forms,causing organisms to grow and reproduce at the normal rate.
D) Oxygen would bind carbon atoms spontaneously,producing more carbon dioxide.

Question 20

The photosynthetic reactions that are dependent on light occur in the

A) thylakoid membrane.
B) stroma.
C) cytosol.
D) nucleus.

Question 21

Which of the following statements best summarizes the events of the Calvin cycle?

A) The cycle uses ATP and NADPH to produce sugars.
B) The cycle moves electrons from photosystem II to photosystem I.
C) The cycle moves light-energized electrons to photosystem II.
D) The cycle absorbs light from the light reactions.

Question 22

The enzyme rubisco is important to the process of

A) catabolism.
B) fermentation.
C) glycolysis.
D) carbon fixation.

Question 23

The first stable product of carbon fixation in C₃ photosynthesis is

A) CO₂.
B) a three-carbon compound called phosphoglyceric acid.
C) citric acid.
D) glyceraldehyde 3-phosphate.

Question 24

Glycolysis is an anaerobic process,which means that glycolytic reactions

A) require no oxygen.
B) produce molecular oxygen.
C) produce ATP.
D) produce citric acid.

Question 25

Which of the following statements about NADP⁺ is true?

A) It is oxidized by photosystem I.
B) It is reduced by photosystem I.
C) It is reduced by photosystem II.
D) It is oxidized by photosystem II.

Question 26

During exercise,the increase in our respiration rate and heartbeat speed is driven by the need to replenish the oxygen used to support

A) lactic acid fermentation.
B) carbon dioxide synthesis in our lungs.
C) oxidative phosphorylation in muscle cell mitochondria.
D) the dark reactions of photosynthesis.

Question 27

Glycolysis occurs in a cell's

A) nucleus.
B) chloroplast.
C) mitochondrion.
D) cytosol.

Question 28

A funnel is used to channel substances that are collected over a wide area into a narrow-necked container.In the Calvin cycle,a funnel might be a good analogy for the

A) reaction center.
B) antenna complex.
C) thylakoid.
D) stoma.

Question 29

The burning pain we feel in our muscles during strenuous exercise is a result of

A) the buildup of lactic acid during fermentation.
B) signals sent to the nervous system by O₂-starved cells.
C) the accumulation of pyruvate in the absence of oxidative phosphorylation.
D) the lack of ATP needed to regulate the pain receptors in our muscle cells.

Question 30

It is reasonable to say that our brain is solar powered because

A) mitochondria in plant cells convert solar power to the chemical power that is used to run the brain.
B) cellular respiration is powered by sunlight.
C) the antenna complex in chloroplasts acts like a tiny solar panel,collecting sunlight to make the sugars we consume to run our brain.
D) mitochondria in plant cells use solar power to split water molecules,creating the energy that runs the brain.

Question 31

When CO₂ levels are low and O₂ levels are high,photosynthesis can be inefficient,because rubisco will add

A) CO₂ to ribulose 1,5-bisphosphate (RuBP)instead of O₂.
B) O₂ to RuBP instead of CO₂.
C) CO₂ to O₂,forming sucrose instead of glucose.
D) CO₂ to a molecule that contains four carbons.

Question 32

The outcome of the Calvin cycle is the

A) capture of energy from sunlight.
B) synthesis of sugars like glucose,fructose,and sucrose.
C) production of pyruvate.
D) breakdown of complex molecules and the subsequent release of energy.

Question 33

During photosynthesis,energized electrons flow from ________ to ________.

A) photosystem I;photosystem II
B) the reaction center;the antenna complex
C) photosystem II;photosystem I
D) the stroma;the intermembrane space

Question 34

Which of the following statements explains how CAM plants have evolved to cope with the dangers of excessive water loss in very hot and dry regions like deserts?

A) They are more efficient at water uptake than are C₃ and C₄ plants.
B) They have special adaptations that cool them off in very hot and dry weather.
C) They close their stomata at night and open them at daybreak to conserve water.
D) They open their stomata at night and close them at daybreak to conserve water.

Question 35

Because inorganic carbon cannot be used by living organisms to build biological molecules,carbon fixation may be the most important metabolic process in the biosphere;if so,the most important enzyme in the biosphere would be

A) chlorophyll.
B) ATP synthase.
C) sucrase.
D) rubisco.

Question 36

The electron transport chains (ETCs)in the chloroplasts and the mitochondria gradually lower the energy content of an electron as it passes from carrier to carrier.This process is similar to the reduction in the energy content of a

A) cannonball that reaches the high point of its flight and then returns to the ground.
B) bowling ball bouncing down a flight of stairs and landing temporarily on each step.
C) pair of sunglasses that intercepts ultraviolet radiation before it reaches our eyes.
D) newly baked pie cooling on the counter before it can be cut and eaten.

Question 37

A fermentation pathway is an oxidative pathway in which the electrons that are released from a nutrient molecule are transferred to molecules created by the catabolism of the nutrient.In lactic acid fermentation,what molecule receives electrons?

A) pyruvate
B) glucose
C) lactic acid
D) ethanol

Question 38

During alcoholic fermentation,why is pyruvate converted to ethanol?

A) to increase the efficiency of cellular respiration by producing additional molecules of ATP
B) to release O₂ as a by-product so that cellular respiration can continue
C) to create lactic acid that will stimulate muscle contraction
D) to recycle NADH back into NAD⁺ so that the cell can continue glycolysis

Question 39

All of the following elements can be found in the photosynthetic intermediary molecules that lead to the production of sugar;which element does NOT remain in the final product?

A) carbon
B) phosphorous
C) hydrogen
D) oxygen

Question 40

The number and arrangement of membranes inside a chloroplast are important to the chloroplast's functions.How would the absence of these membranes affect the manufacture of ATP in a chloroplast?

A) The chloroplast would be unable to maintain the proton gradient required for ATP production.
B) The chloroplast would be unable to capture ATP directly from the sun.
C) The chloroplast would be unable to perform the Calvin cycle.
D) The chloroplast would be unable to perform anaerobic respiration.

Question 41

You have shrunk to molecular size and find yourself in a chamber inside a chloroplast where protons are being pumped into another chamber.You are in the ________.

Question 42

Which of the following substances is NOT a respiratory poison?

A) rotenone
B) carbonic anhydrase
C) cyanide
D) carbon monoxide

Question 43

The innermost membrane in a chloroplast is the ________ membrane.

Question 44

The process that produces ATP from sugars begins with glycolysis;when fatty acids are used as nutrients to generate ATP instead of sugars,the process begins with

A) oxidative phosphorylation.
B) the Calvin cycle.
C) the electron transport chain.
D) the Krebs cycle.

Question 45

The light reactions in photosynthesis result in three output products: molecular oxygen,ATP,and ________.

Question 46

The Krebs cycle produces

A) NADH and carbon dioxide.
B) water and carbon dioxide.
C) ADP and NADP⁺.
D) acetyl CoA and sugars.

Question 47

Most of the oxidation reactions that produce NADH in a cell take place in

A) the Krebs cycle.
B) glycolysis.
C) photosynthesis.
D) the electron transport chain.

Question 48

The molecular energy carrier that has less energy than other energy carriers but is more versatile because of its ability to be used in a larger variety of chemical reactions is ________.

Question 49

Light consists of massless particles called photons,each of which travels through space with a wavelike oscillation.Photons that have more energy content have wavelengths that are ________.

Question 50

The type of reaction that breaks down food molecules and gradually oxidizes them to produce energy is a(n)________ reaction.

Question 51

The green pigment that is most commonly associated with photosynthesis is ________.

Question 52

In mitochondria,the energy that electrons release as they move through the electron transport chain is used to transport

A) electrons from the thylakoid matrix to the cytosol.
B) acetyl CoA into the Krebs cycle.
C) protons into the mitochondrial intermembrane space.
D) pyruvate into the first reaction of glycolysis.

Question 53

NAD⁺ becomes NADH when it gains one proton and two high-energy ________.

Question 54

The inner membrane of a mitochondrion has many folds.Why?

A) The folds protect the proteins in the inner membrane from the toxic by-products of cellular respiration.
B) The folds increase the space available for electron transport chains and ATP synthase molecules,increasing the efficiency of ATP production.
C) The extra folds make the mitochondrion more efficient at capturing carbon dioxide.
D) The antenna complexes in the inner membrane form clusters that force the membrane into folds.

Question 55

The conversion of inorganic carbon from air into the carbon atoms found in all living organisms is known as carbon ________.

Question 56

The Krebs cycle takes place in the

A) mitochondrial matrix.
B) cytosol.
C) thylakoid membrane.
D) outer mitochondrial membrane.

Question 57

Not all visible light supports photosynthesis;the chlorophyll molecules in an antenna complex can be excited only by those wavelengths that are colored ________ and ________.

Question 58

World-class sprinters typically do not breathe during the 9+ seconds it takes to complete a 100-meter race.What does this fact suggest about these runners' energy production?

A) It must be mitochondrial,with oxygen provided by one big breath at the beginning of the sprint.
B) It must be mitochondrial,with oxygen provided by circulating hemoglobin that is already saturated with oxygen.
C) It must be glycolytic;the process is entirely anaerobic and the race will be over before NADH⁺ reserves are depleted.
D) It must be fermentative,which explains why most sprinters experience cramping after the race ends.

Question 59

The energy source that makes oxidative phosphorylation possible comes from

A) phosphate group transfers from ATP.
B) electrons that are transferred from NADPH.
C) electrons that are transferred from NADH.
D) electrons that are removed from CO₂ during its oxidation.

Question 60

Acetyl CoA donates the two-carbon acetyl group to a four-carbon acceptor molecule to begin what process?

A) glycolysis
B) the Krebs cycle
C) the electron transport chain
D) the Calvin cycle

Question 61

The respiratory poison that shuts down ATP production by mitochondria and smells like bitter almonds is ________.

Question 62

Plants that live in very dry regions where they are subject to the dangers of extreme water loss through their stomata open their stomata only at night,when the temperature is lower and the air is not as dry.These plants are referred to as ________ plants.

Question 63

Organisms that require oxygen to extract energy from food are ________.

Question 64

In warm and dry conditions,when CO₂ levels fall and O₂ levels rise,photorespiration occurs as a result of plants closing their ________.

Question 65

In mitochondria,ATP is produced in conjunction with proteins in the membrane that surrounds a region in the mitochondrion known as the ________.

Question 66

When yeasts are exposed to anaerobic conditions,they regenerate NAD⁺ from NADH in a series of reactions that make CO₂ and ________.

Question 67

An electron transport chain is made up of a group of membrane-embedded,electron-accepting ________.

Question 68

The most common cause of death by poisoning around the world is ________.

Question 69

The process that converts NADH into NAD⁺ to keep glycolysis running under anaerobic conditions is called ________.

Question 70

The muscle cells of a very active organism would contain fewer mitochondria than those of a less active organism.

Question 71

The mitochondria of plant cells contain thylakoids.

Question 72

Electrons gain energy as they move through the electron transport chain.

Question 73

The energy that is needed to produce the flash of a firefly originally comes from sunlight.

Question 74

Cellular respiration is essentially the opposite of photosynthesis.

Question 75

You have shrunk to molecular size and find yourself in a mitochondrial chamber where protons are being pumped out of the chamber and across a membrane into another chamber.You are in the mitochondrion's ________.

Question 76

In C₄ plants,carbon fixation and the workings of rubisco are spatially separated.Carbon fixation occurs in the ________ cells,and then rubisco adds CO₂ to RuBP in ________ cells.

Question 77

Energy is used to force protons from the thylakoid space back into the stroma.

Question 78

During the Calvin cycle,the enzyme rubisco forms an unstable carbohydrate by combining CO₂ with a compound that contains ________ carbons.(Hint: The answer is a number. )

Question 79

ATP synthase is a protein that participates in the redox reactions of the electron transport chain.

Question 80

The series of chemical reactions that begins with rubisco adding oxygen to ribulose 1,5-bisphosphate (RuBP)and ends with the release of CO₂ is called ________.