Deck 4: How Cells Work

Question 1

Carbon dioxide is one product of a metabolic process, which occurs in both plants and animals. This process is called

A)catalysis.
B)glycolysis.
C)respiration.
D)photosynthesis.

Answer 1

C

Question 2

Enzymes can catalyze a reaction only if

A)they encounter a molecule of ATP.
B)their active site is sufficiently oxidized.
C)they have both products in their active site at the same time.
D)they encounter a substrate that fits their active site.

Answer 2

D

Question 3

Which of the following is a similarity between photosynthesis and respiration?

A)Neither is a metabolic process.
B)They are both metabolic processes.
C)Neither is an anabolic process.
D)They are both mainly anabolic processes.

Answer 3

B

Question 4

A given enzyme

A)can be used for many different kinds of chemical reactions.
B)is permanently changed during a chemical reaction.
C)has a special site where the products bind before the reaction begins.
D)increases the rate of a particular reaction.

Question 5

Chemical reactions that break down lipids are

A)catabolic.
B)anabolic.
C)metabolic.
D)respiration.

Question 6

In the reaction C₆H₁₂O₆ + 6 O₂ à 6 CO₂ + 6 H₂O, the 6 CO₂ molecules are some of the

A)substrates.
B)products.
C)enzymes.
D)reactants

Question 7

The image below diagrams the action of an enzyme. Notice that the enzyme is depicted as being more tightly wrapped around the substrates in step 2 than it is in step 1. Why is this?

A)When a substrate locks into the active site of an enzyme, the enzyme changes shape to mold itself around the substrates.
B)Generally, the size of a substrate is larger than the size of the active site into which it must fit. When the substrate enters the active site, the active site must stretch to fit.
C)Before catalysis can occur, a substrate must change its shape so that it fits into the active site of the enzyme more precisely.
D)Most active sites are only designed to hold one substrate. In this image, two substrates enter the active site, creating a tighter fit.

Question 8

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

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

Question 9

In a human cell,

A)one enzyme usually catalyzes no more than five different chemical reactions.
B)nearly all chemical reactions are catalyzed by enzymes.
C)enzymes have to be constantly replaced as they are used up in the reactions that they catalyze.
D)some enzymes are specialized to store activation energy.

Question 10

The illustration below indicates that photosynthesis and cellular respiration are both complementary and balanced. An excess of sugars produced fossil fuels like coal and petroleum; this suggest that in the past,

A)the amount of photosynthesis occurring exceeded the amount of cellular respiration.
B)sugars were only one of several products of photosynthesis.
C)reduced carbon-rich molecules could be produced independently from the photosynthetic process.
D)the energy release from respiration must have exceeded energy use in photosynthesis.

Question 11

Photosynthesis and cellular respiration are both complementary and relatively balanced, but early history of life on Earth showed increasing oxygen concentrations. This indicates that

A)both photosynthesis and respiration were occurring at approximately the same levels.
B)neither photosynthesis nor respiration were occurring.
C)the amount of photosynthesis occurring exceeded the amount of cellular respiration.
D)the amount of cellular respiration occurring exceeded the amount of photosynthesis.

Question 12

A chemical reaction that uses ATP to build cellular components is

A)catabolic.
B)anabolic.
C)photosynthetic.
D)respiration.

Question 13

Photosynthetic organisms capture energy from sunlight and convert it into chemical bonds by forming

A)sugars.
B)enzymes.
C)work.
D)substrates.

Question 14

What should the arrow in the following equation be labeled? Sugar + oxygen à carbon dioxide + water + ATP.

A)photosynthesis
B)cellular respiration
C)Krebs cycle
D)Calvin cycle

Question 15

________ reactions release energy by breaking down complex molecules.

A)Catabolic
B)Anabolic
C)Photosynthetic
D)Respiration

Question 16

In the reaction H₂O + CO₂ + carbonic anhydrase à H⁺ + HCO₃⁻+ carbonic anhydrase, carbonic anhydrase is a(n)

A)reactant.
B)product.
C)enzyme.
D)active site.

Question 17

The first law of thermodynamics states that

A)metabolic reactions must be balanced.
B)the flow of energy connects living things to their environments.
C)energy cannot be created nor destroyed.
D)systems tend to become more disorderly.

Question 18

The energy required for life processes must be extracted from an organism's

A)nucleus.
B)environment.
C)predators.
D)biosynthesis.

Question 19

The capture and use of energy by living organisms involves numerous chemical reactions. Collectively these processes are known as

A)metabolism.
B)respiration.
C)anabolic reactions.
D)catabolic reactions.

Question 20

In many organelles, groups of different enzymes are located on membranes in close proximity to each other because

A)attaching enzymes to the membrane prevents the cell from losing them to the surrounding environment.
B)when enzymes are in close proximity, each one can catalyze more than one type of reaction.
C)these enzymes are involved in the same metabolic pathway and keeping them closer together increases the efficiency of the pathway.
D)all enzymes must act in groups to position substrates in the proper orientation to produce the product.

Question 21

As an energy carrier, ATP differs from NADPH in that

A)ATP transfers energy through phosphorylation, whereas NADPH donates electrons and hydrogen ions.
B)ATP transfers energy through redox reactions, whereas NADPH uses phosphorylation.
C)NADPH is involved in a larger variety of chemical reactions than ATP.
D)NADPH is made by Photosystem I, whereas ATP is made by Photosystem II.

Question 22

Which of the following statements describe the function of the light reaction in photosynthesis?

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

Question 23

The enzyme rubisco is important to the process of

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

Question 24

What 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 25

Glycolysis is an anaerobic process, indicating that the glycolytic reactions

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

Question 26

Which of the following is either consumed or synthesized in virtually every cellular reaction?

A)sugars
B)enzymes
C)DNA
D)ATP

Question 27

Which of the following statements comparing photosynthesis and cellular respiration is accurate?

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 28

When ATP breaks down into ADP and a phosphate group,

A)energy is absorbed by ADP and transferred to enzymes.
B)energy is released and can power cellular activities.
C)ADP becomes the active site in an enzyme.
D)the energy in the broken bond is transferred to the phosphate group.

Question 29

Which of these carries the most energy?

A)ADP
B)ATP
C)NADH
D)NAD+

Question 30

Some kinds of drain cleaners use enzymes rather than strong, more dangerous chemicals. These enzymes must be able to

A)catalyze a catabolic reaction.
B)raise the energy of the reaction that clears the clog.
C)create energy that can be used to break up the clog.
D)catalyze an anabolic reaction.

Question 31

Examine the illustration below. Which statement best summarizes the contribution of Photosystem I (PSI) during photosynthesis?

A)PSI provides the initial energy boost to the electrons on their way to Photosystem II (PSII).
B)PSI generates the excited electrons that initially accumulate within the thylakoid space and eventually drive ATP synthesis.
C)PSI generates the high-energy electrons that are transported by NADPH to the Calvin cycle and will eventually reduce the carbon in CO₂.
D)PSI regulates the transmembrane passage of protons through the thylakoid membrane.

Question 32

A plant cell is mutated so ATP synthase no longer functions. Which process will be affected?

A)photosynthesis only
B)respiration only
C)both photosynthesis and respiration
D)neither photosynthesis nor respiration

Question 33

In photosynthesis, the carbon used to make sugars is

A)provided by enzymes.
B)provided by carbon dioxide.
C)extracted from DNA.
D)oxidized to make sugars.

Question 34

Plants and animals use different energy storage molecules, yet they both use the same mechanism to "burn" their stored energy. How can plants and animals both be successful, even though they "burn" different energy storage molecules?

A)The internal components of plant and animal cells are identical.
B)The second law of thermodynamics says that all cells have the same energy transfer system.
C)The breaking of the chemical bonds of a storage molecule transfers energy, no matter what molecule is stored.
D)All organisms have the same enzymes to catalyze their energy-producing reactions.

Question 35

The three stages of cellular respiration (in order) 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 36

The energy carriers NADPH and NADH differ structurally. Functionally they

A)are quite similar; each is produced in catabolic pathways and is used in anabolic pathways.
B)are quite similar; each is produced in anabolic pathways and is used in catabolic pathways.
C)are somewhat different; NADPH is produced from catabolic processes, whereas NADH is used in anabolic processes.
D)are somewhat different; NADH is produced from catabolic processes, whereas NADPH is used in anabolic processes.

Question 37

The chemical 3-(3,4-dichloro-phenyl)-1,1-dimethylurea (DCMU) blocks the movement of electrons at the point indicated by the black, downward-pointing arrow in the figure below. Which of the following would be an immediate effect of treating a chloroplast with this drug?

A)Water molecules would be split at a faster rate than when the drug is not present.
B)The amount of NADPH produced by the light reactions would increase.
C)A proton gradient would not be created, so ATP could not be made.
D)The production of water would increase.

Question 38

Cells contain the molecule GTP (guanosine triphosphate). Would this molecule be useful as an energy carrier (similar to ATP)?

A)No, because it does not contain the adenosine necessary for storing energy.
B)No, because it contains fewer phosphates than ATP.
C)Yes, because it contains a nitrogenous base just like ATP.
D)Yes, because it contains the same number of phosphates as does ATP.

Question 39

What is the role of water in photosynthesis?

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

Question 40

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

A)carbon dioxide.
B)ATP.
C)water.
D)NADPH.

Question 41

Two students are discussing the importance of glycolysis in human cells. One student states that the main function of glycolysis is to produce ATP. The other states that the main function is to produce NADH. Which student is correct?

Question 42

Excess carbon dioxide in the atmosphere is increasing climate change. How do photosynthesis and cellular respiration relate to this issue and how can we use this knowledge to help decrease this problem?

Question 43

Cells would not be able to survive unless anabolic and catabolic processes occurred in linked reactions. Support or refute this statement.

Question 44

Photosynthesis and cellular respiration cycle the element ________ through the environment. When a plant does photosynthesis, it takes this element from the air and produces sugars. When animals conduct cellular respiration, they break down sugars and exhale a gas that contains this element.

Question 45

A cell is found that is able to use sunlight to produce ATP, but it does not produce NADPH. The portion of the light reaction that is not functioning is ________.

Question 46

The step of cellular respiration that produces a product that will eventually be used in the Calvin cycle is the ________.

Question 47

The sequential reaction pathway A à B à C à D is dependent on enzymes for each separate step. The enzyme which has "C" as a substrate becomes nonfunctional. Explain how this affects the metabolic pathway shown.

Question 48

The evolution of photosynthesis was an essential event for the evolution of life as we know it. Defend this statement by discussing the importance of the products of photosynthesis.

Question 49

A mutation in a plant cell produces rubisco enzymes, which can only bind O₂ (and not CO₂). What would be the outcome of this mutation?

Question 50

Which of the following molecules carries electrons to the electron transport chain of oxidative phosphorylation?

A)ATP
B)NADH
C)CO₂
D)ADP

Question 51

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

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

Question 52

The Krebs cycle produces

A)NADH, ATP, and FADH2.
B)water and carbon dioxide.
C)ADP and NADP+.
D)acetyl CoA and sugars.

Question 53

What would occur if the mitochondria of a cell did not produce an inner membrane?

A)The mitochondria would be unable to maintain the proton gradient required for ATP production.
B)The mitochondria would be unable to capture ATP from the sun.
C)The mitochondria would be unable to perform the Krebs cycle.
D)The mitochondria would be unable to perform glycolysis.

Question 54

Humans store sugars in the form of glycogen. Glycogen is made by linking many glucose molecules together. This process is ________.

Question 55

Which step of cellular respiration occurs outside the mitochondria?

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

Question 56

A hypothetical chemical forms a permanent bond between the phosphates in ATP. How would this affect the cell?

Question 57

A new bacterial cell is found that is able to grow without food as long as sunlight is available. This cell likely uses ________ to produce its own food.

Question 58

The ________ of an enzyme is an area with a specialized shape and/or set of chemical properties that allows the enzyme to bind with a particular substrate.

Question 59

For each characteristic below, state if it applies to photosynthesis and/or cellular respiration.
a.photosynthesis only
b.cellular respiration only
c.both photosynthesis and cellular respiration
d.neither photosynthesis nor cellular respiration
produces carbon dioxide

Question 60

A protein in the cell membrane is used to transport molecules against their concentration gradient (a process that requires energy). This protein likely also binds to ________ in addition to the molecule it is transporting.

Question 61

For each characteristic below, state if it applies to photosynthesis and/or cellular respiration.
a.photosynthesis only
b.cellular respiration only
c.both photosynthesis and cellular respiration
d.neither photosynthesis nor cellular respiration
produces sugars

Question 62

For each characteristic below, state if it applies to photosynthesis and/or cellular respiration.
a.photosynthesis only
b.cellular respiration only
c.both photosynthesis and cellular respiration
d.neither photosynthesis nor cellular respiration
used by plant cells

Question 63

For each characteristic below, state if it applies to photosynthesis and/or cellular respiration.
a.photosynthesis only
b.cellular respiration only
c.both photosynthesis and cellular respiration
d.neither photosynthesis nor cellular respiration
produces light energy

Question 64

For each characteristic below, state if it applies to photosynthesis and/or cellular respiration.
a.photosynthesis only
b.cellular respiration only
c.both photosynthesis and cellular respiration
d.neither photosynthesis nor cellular respiration
used by animal cells