Unit 4: HW 12 on Metabolism

Question 1

Most of the energy released by oxidizing glucose is saved in the high-energy bonds of what molecules?

Choose one:
	A. GDP and other activated carriers
	B. O2
	C. ADP and other activated carriers
	D. H2O and CO2
	E. ATP and other activated carriers

Answer 1

E. ATP and other activated carriers

Question 2

Useful energy is obtained by cells when sugars derived from food are broken down by which processes?

Choose one:
A. gluconeogenesis, the citric acid cycle, and oxidative phosphorylation
B. glycolysis, the citric acid cycle, and oxidative phosphorylation
C. gluconeogenesis, fermentation, and oxidative phosphorylation
D. glycolysis, the citric acid cycle, and gluconeogenesis
E. glycolysis, the Calvin cycle, and oxidative phosphorylation

Answer 2

B. glycolysis, the citric acid cycle, and oxidative phosphorylation

Question 3

Where does the oxidative (oxygen-dependent) stage of the breakdown of food molecules occur in a eukaryotic cell?

Choose one:
	A. mitochondrion
	B. Golgi apparatus
	C. cytosol
	D. endoplasmic reticulum

Answer 3

A. mitochondrion

Question 4

Which of the following processes generates the largest number of ATP molecules?

Choose one:
	A. citric acid cycle
	B. gluconeogenesis
	C. glycolysis
	D. electron transport chain
	E. fermentation

Answer 4

D. electron transport chain

Question 5

Under anaerobic conditions, which metabolic pathway regenerates the supply of NAD+ needed for glycolysis?

Choose one:
	A. citric acid cycle
	B. formation of acetyl CoA
	C. breakdown of amino acids
	D. breakdown of fats
	E. fermentation

Answer 5

E. fermentation

Question 6

Although the citric acid cycle itself does not use O2, it requires a functioning electron transport chain (which uses O2) in order to regenerate which molecule for further use in the citric acid cycle?

Choose one:
	A. NAD+
	B. NADH
	C. FADH2
	D. ATP
	E. ADP

Answer 6

A. NAD+

Question 7

The NADH generated during glycolysis and the citric acid cycle feeds its high-energy electrons to which of the following?

Choose one:
	A. ADP
	B. H2O
	C. the citric acid cycle
	D. the electron transport chain
	E. FAD

Answer 7

D. electron transport chain

Question 8

In eukaryotic cells, what is the final electron acceptor in the electron transport chain?

Choose one:
	A. CO2
	B. O2
	C. FADH2
	D. ATP
	E. NAD+

Answer 8

B. O2

Question 9

In the electron transport chain, the oxygen atoms in O2 become part of which of the following molecules?

Choose one:
	A. CO2
	B. NADH
	C. H2O
	D. ATP
	E. glucose (C6H12O6)

Answer 9

C. H2O

Question 10

Which two-carbon molecule enters the citric acid cycle?

Choose one:
	A. acetyl CoA
	B. oxaloacetate
	C. pyruvate
	D. carbon dioxide
	E. citrate

Answer 10

A. acetyl CoA

Question 11

What occurs in the first step of the citric acid cycle?

Choose one:
A. A two-carbon molecule is combined with a four-carbon molecule to form citrate.
B. CO2 is released.
C. Two molecules of acetyl CoA combine to form oxaloacetate.
D. ATP is consumed.
E. NADH is produced.

Answer 11

A. A two-carbon molecule is combined with a four-carbon molecule to form citrate.

Question 12

Question 12: CO2 is released in which steps of the citric acid cycle, as shown below?

Answer 12

Choose one:
	STEP 3 AND 4
	Steps 2 and 4
	Steps 2, 3, and 4
	Steps 1 and 8
	Steps 1 and 5

Question 13

The ethanol in wine and beer is produced from metabolic reactions carried out by the yeast Saccharomyces cerevisiae. Since it is of great commercial value, researchers have studied factors that influence ethanol production. To maximize ethanol yield, which environmental factor should be limiting?

Choose one:
A.  	oxygen
B.  	sunlight
C.  	carbon dioxide
D.  	glucose

Answer 13

A. oxygen

Question 14

How do enzymes maximize the energy harvested from the oxidation of food molecules?

Choose one:
A. They allow a larger amount of energy to be released from food molecules such as glucose.
B. They guarantee that each reaction involved in the oxidation of food molecules proceeds in just one direction.
C. They allow oxidation reactions to take place without an input of activation energy.
D. They allow what would otherwise be an energetically unfavorable oxidation reaction to occur.
E. They allow the stepwise oxidation of food molecules, which releases energy in small amounts.

Answer 14

E. They allow the stepwise oxidation of food molecules, which releases energy in small amounts.

Question 15

What happens to the energy captured during glycolysis and the citric acid cycle by the activated carriers NADH and FADH2.

Choose one:
A. It is passed to an electron transport chain that uses it to produce oxygen.
B. It is passed to ADP to form ATP.
C. It is passed to an electron transport chain that uses it to generate a proton gradient across the inner mitochondrial membrane.
D. It is used to drive biosynthetic reactions.
E. It is passed to an electron transport chain that uses it to oxidize food molecules.

Answer 15

C. It is passed to an electron transport chain that uses it to generate a proton gradient across the inner mitochondrial membrane.

Question 16

What does the term “gluconeogenesis” refer to?

Choose one:
A. the transport of glucose across a cell membrane
B. the breakdown of glucose during glycolysis
C. the synthesis of glucose from small organic molecules such as pyruvate
D. the release of glucose from molecules such as glycogen
E. the breakdown of glucose during fermentation

Answer 16

C. the synthesis of glucose from small organic molecules such as pyruvate

Question 17

When food is plentiful, animals can store glucose as what?

Choose one:
	A. glycogen
	B. acetyl CoA
	C. glucose 6-phosphate
	D. starch
	E. glycogen or starch

Answer 17

A. glycogen

Question 18

When nutrients are plentiful, plants can store glucose as what?

Choose one:
	A. starch
	B. glucose 6-phosphate
	C. fats
	D. glycogen
	E. glycogen and starch

Answer 18

A. starch

Question 19

In what form do plant and animal cells store fat?

Choose one:
	A. triacylglycerol
	B. starch
	C. glycogen
	D. phospholipids
	E. nitroglycerin

Answer 19

A. triacylglycerol

Question 20

You are packing for a hiking trip during which you’ll be burning a lot of calories with physical activity. You want to pack as efficiently as possible since you need to carry a tent and all your food. You can get the most calories out of 5kg of food if it is in the form of __________.

Answer 20

fat

Question 21

Which of the following describes a breakdown process in which enzymes degrade complex molecules into simpler ones?

Choose one:
	A. anabolism
	B. metabolism
	C. catabolism
	D. Enzymes are not needed to break down complex molecules into simpler ones.

Answer 21

C. catabolism

Question 22

In which of the following locations are polymeric food molecules digested into their monomeric subunits?

Choose one or more:
the cell cytosol
lysosomes
extracellular space

Answer 22

lysosomes

extracellular space

Question 23

What are the end products of glycolysis?

Choose one or more:
	NADPH
	ADP
	acetyl CoA
	NADH
	H2O + CO2
	ATP
	pyruvate

Answer 23

NADH
ATP
pyruvate

Question 24

How many ATP molecules must be invested during the first part of glycolysis for each molecule of glucose broken down?

Choose one:
	four
	30
	It depends on whether oxygen is present.
	one
	two
	none

Answer 24

two

Question 25

From one glucose molecule, how much net energy (in the form of ATP and NADH) is produced during glycolysis? ``` Choose one: A. 2 ATP, 2 NADH B. 4 ATP, 4 NADH C. 2 ATP, 4 NADH D. 4 ATP, 2 NADH ```

Answer 25

A. 2 ATP, 2 NADH

Question 26

The synthesis of ATP in glycolysis occurs by which process? ``` Choose one: oxidative phosphorylation a transfer of electrons from NADH substrate-level phosphorylation substrate-level dephosphorylation a transfer of phosphate from AMP ```

Answer 26

substrate-level phosphorylation

Question 27

For many anaerobic microorganisms, which metabolic pathway is the principal source of ATP? ``` Choose one: A. citric acid cycle B. Calvin cycle C. gluconeogenesis D. glycolysis E. oxidative phosphorylation ```

Answer 27

D. glycolysis

Question 28

What type of enzyme catalyzes the rearrangement of chemical bonds within a single molecule? ``` Choose one: A. isomerase B. dehydrogenase C. kinase D. scramblase ```

Answer 28

A. isomerase

Question 29

What type of enzyme catalyzes the shifting of a chemical group from one position in a molecule to another? ``` Choose one: A. dehydrogenase B. flippase C. mucinase D. mutase E. kinase ```

Answer 29

D. mutase

Question 30

Which of these glycolytic reactions is catalyzed by a kinase? Choose one or more: dihydroxyacetone phosphate → glyceraldehyde 3-phosphate 3-phosphoglycerate → 2-phosphoglycerate glucose 6-phosphate → fructose 6-phosphate glyceraldehyde 3-phosphate → 1,3-bisphosphoglycerate 1,3-bisphosphoglycerate → 3-phosphoglycerate glucose → glucose 6-phosphate fructose 6-phosphate → fructose 1,6-bisphosphate

Answer 30

1,3-bisphosphoglycerate → 3-phosphoglycerate glucose → glucose 6-phosphate fructose 6-phosphate → fructose 1,6-bisphosphate

Question 31

Which reaction releases the most energy? Choose one: A. hydrolysis of 1,3-bisphosphoglycerate to 3-phosphoglycerate B. hydrolysis of glucose 6-phosphate to glucose C. hydrolysis of ATP to ADP D. transfer of phosphate group from ATP to glucose E. hydrolysis of ADP to AMP

Answer 31

A. hydrolysis of 1,3-bisphosphoglycerate to 3-phosphoglycerate

Question 32

The citric acid cycle converts the carbon atoms in acetyl CoA to which of the following? ``` Choose one: A. pyruvate B. citrate C. oxaloacetate D. CO2 E. glucose ```

Answer 32

D. CO2

Question 33

When fatty acids are oxidized to produce acetyl CoA, each cycle of the reaction removes how many carbon atoms from the fatty acid molecule? Choose one: A. 1 B. It depends on whether the initial fatty acid has an even or an odd number of carbons. C. Fatty acids are not oxidized to produce acetyl CoA. D. 2 E. 3

Answer 33

D. 2

Question 34

About how many molecules of ATP are produced by the complete oxidation of glucose to H2O and CO2? ``` Choose one: A. 2 ATPs from glycolysis + 1 GTP from the citric acid cycle B. 3 C. 30 D. 4 E. 2 ```

Answer 34

C. 30

Question 35

Determine whether the following statement is true or false: The oxygen consumed during the oxidation of glucose in animal cells is returned to the atmosphere as CO2. Choose one: false true

Answer 35

false

Question 36

The oxygen atoms required for the citric acid cycle to produce CO2 ultimately are derived from which of the following? ``` Choose one: A. molecular oxygen B. water C. the mitochondrial membrane D. glucose E. oxaloacetate ```

Answer 36

B. water

Question 37

36. In step 6 of glycolysis, glyceraldehyde 3-phosphate, which has one phosphate group, is converted into 1,3-bisphosphoglycerate, which has two. Where does the extra phosphate group come from? ``` Choose one: A. ATP B. ADP C. inorganic phosphate D. NADPH E. fructose 1,6-bisphosphate ```

Answer 37

C. inorganic phosphate

Question 38

In plant cells, where does the citric acid cycle take place? ``` Choose one: A. cytosol B. mitochondria C. chloroplasts and mitochondria D. chloroplasts E. The citric acid cycle does not occur in plant cells. ```

Answer 38

B. mitochondria

Question 39

During the citric acid cycle, what happens to the acetyl group in acetyl CoA? ``` Choose one: A. It is vaporized to produce CO2. B. It is oxidized to produce CO2. C. It is eliminated to produce CO2. D. It is reduced to produce CO2. E. It is hydrolyzed to produce CO2. ```

Answer 39

B. It is oxidized to produce CO2.

Question 40

For each acetyl group that enters the citric acid cycle, what activated carriers are produced? ``` Choose one: A. three NADPH, one FADH2, one GTP B. three NADH, one FAD, one GTP C. three NADH, one FADH2, one GTP D. three NADH, two FADH2, one GTP E. three NADH, one FADH2, one ATP ```

Answer 40

C. three NADH, one FADH2, one GTP

Question 41

What does the pyruvate dehydrogenase complex do? Choose one: A. It completes the oxidation of pyruvate to CO2 in the mitochondrial matrix. B. It produces pyruvate in the cytosol. C. It converts pyruvate into acetyl CoA in the mitochondrial matrix. D. It regenerates NAD+ in the mitochondrial matrix. E. It converts pyruvate into acetyl CoA in the cytosol.

Answer 41

C. It converts pyruvate into acetyl CoA in the mitochondrial matrix.

Question 42

In humans and other mammals, gluconeogenesis is most likely to occur in which type of cells? ``` Choose one: A. red blood cells B. pancreatic cells C. liver cells D. nerve cells E. muscle cells ```

Answer 42

C. liver cells

Question 43

Which statement is true of glycogen phosphorylase? Choose one: A. It is inhibited by glucose 6-phosphate and by ATP. B. It is activated by glucose 6-phosphate, but inhibited by ATP. C. It is inhibited by glucose 6-phosphate, but activated by ATP. D. It is activated by glucose 6-phosphate and by ATP. E. It stimulates gluconeogenesis.

Answer 43

A. It is inhibited by glucose 6-phosphate and by ATP.

Question 44

Question 44: Below is a table listing the reactions that constitute the 10 steps of glycolysis, along with the change in free energy (ΔG°) for each step. Based on the data, which steps in glycolysis are effectively irreversible?

Answer 44

``` Choose one: Steps 6 and 7 Step 1 Steps 1, 2, 3, 4, 6, and 10 Steps 5, 7, 8, and 9 Steps 1, 3, 7, and 10 STEPS 1, 3, and 10 ```