Exam 3

Question 1

Critical hormones that signal for glycogen breakdown are:

Answer 1

Epinephrine, glucagon

Question 2

Acyl groups generated during metabolic processes involving carbohydrates and fatty acids are activated by attachment to ____

Answer 2

coenzyme A

Question 3

The major sites of glycogen storage are:

Answer 3

liver and skeletal muscle

Question 4

Large enzyme complex that links glycolysis and the citric acid cycle under aerobic conditions is____

Answer 4

pyruvate dehydrogenase

Question 5

The electron-transport chain and ATP synthase are effectively coupled. Which statement best describes how this occurs?
Through a series of conformational changes, ATP synthase generates ATP.
The electron-transport chain reoxidizes reduced cofactors.
ATP synthase utilizes oxidized cofactors.

Answer 5

The electron-transport chain generates an electrochemical gradient that provides energy for the production of ATP

Question 6

The citric acid cycle runs only in the presence of oxygen, but no oxygen is required for the cycle. What is the link between Citric Acid Cycle and oxygen?

Answer 6

The citric acid cycle depends on steady supply of NAD+, which is generated from NADH by reaction with oxygen. Oxygen serves as a final electron acceptor.

Question 7

Electron flow down the electron-transport chain leads to the ____

Answer 7

Transport of protons across the inner mitochondrial membrane from inside the matrix to the intermembrane space

Question 8

Where is the place for pyruvate decarboxylation in the cell?

Answer 8

Mitochondrial matrix

Question 9

The bonds connecting glucose residues in the glycogen molecule are

Answer 9

Mostly glucosidic alpha 1 –> 4 bond with some alpha 1 –> bonds at branching points

Question 10

What would be the limiting factor for ATP production by glycolysis in strenuously exercising muscle that lacks lactate dehydrogenase?

Answer 10

The supply of NAD+

Question 11

The degradation of an 18-carbon saturated fatty acid would be expected to yield how many NADH and FADH2 per fatty acid molecule?

Answer 11

8

Question 12

What reactions of glycolysis are bypassed by the 4 steps of gluconeogenesis?
Reaction catalyzed by pyruvate carboxylase.
Reaction catalyzed by phosphoenolpyruvate carboxikinase.
Reaction catalyzed by pryuvate kinase.
Reaction catalyzed by phosphofructokinase.
Reaction catalyzed by hexokinase.

Answer 12

Reaction catalyzed by pryuvate kinase.
Reaction catalyzed by phosphofructokinase.
Reaction catalyzed by hexokinase.

Question 13

The molecule ____ stimulates lipolysis when level of blood glucose is low

Answer 13

glucagon

Question 14

If skeletal muscles work to the point of fatigue, the muscle cells may not have sufficient oxygen to carry out aerobic respiration. What processes do muscle cells use if oxygen is not available?

Answer 14

Lactic acid fermentation
Glycolysis

Question 15

Surplus amino acids are ____.

Answer 15

Used as metabolic fuel

Question 16

What are the precursors of glucose? Select all that apply.
Fatty acids.
Glycerol.
Amino acids.
Lactate.
Acetyl CoA.

Answer 16

Glycerol
Amino acids
Lactate

Question 17

Glyceraldehyde 3-phosphate can be converted into

Answer 17

Pyruvate or glucose in the liver

Question 18

When glucose is completely oxidized to CO2 and H2O, how many ATP molecules are made by oxidative phosphorylation relative to the maximum yield?

Answer 18

36 out of 30

Question 19

Select the statement that best describes the purpose of the urea cycle in the cells of land mammals.
To convert highly toxic free ammonia into less toxic urea.
To convert highly toxic urea into less toxic free ammonia.
To produce NADPH for fatty acid synthesis.
To produce fumarate for the citric acid cycle.

Answer 19

To convert highly toxic free ammonia into less toxic urea

Question 20

In aerobic organisms, this is the ultimate acceptor of electrons

Answer 20

O2

Question 21

Choose the statement that sums up reciprocal regulation of gluconeogenesis and glycolysis:
When glucose is abundant, glycolysis will be stopped.
When glucose is abundant, glycolysis will predominate.
When glucose is abundant, gluconeogenesis will predominate.
When glucose is scarce, glycolysis will predominate.
When glucose is abundant, glycogenolysis will predominate.

Answer 21

When glucose is abundant, glycolysis will predominate

Question 22

Almost all of the oxygen (O2) one consumes in breathing is converted to ____

Answer 22

Water

Question 23

Which of the following is not a component of the citric acid cycle?

Answer 23

Propionyl Co-A

Question 24

What type of bond is glycogen phosphorylase able to cleave?

Answer 24

Alpha-1,4-glycosidic bond at a glycogen brunch

Question 25

What donates electrons to the ETC?

Answer 25

NADH and FADH2

Question 26

Triacylglycerols are stored in ____ cells in animals.

Answer 26

Adipose

Question 27

Which of the following is not true of glycolysis? It requires an input of ATP to begin. It produces NADH. It is anaerobic. It occurs in the cytoplasm. It produces 4 net ATP.

Answer 27

It produces 4 net ATP

Question 28

Which of the following molecule(s) have a higher phosphoryl-transfer potential than ATP? Glucose-6 phosphate. Pyrophosphate (PPi). Glycerol phosphate. 1,3-bisphosphoglycerate (1,3-BPG). Creatine phosphate. Phosphoenolypyruvate (PEP)

Answer 28

1,3-bisphosphoglycerate (1,3-BPG). Creatine phosphate. Phosphoenolpyruvate (PEP)

Question 29

This is the product of the complete oxidation of carbon in the citric acid cycle

Answer 29

CO2

Question 30

What metal is present in ALL complexes of electron transport chain?

Answer 30

Iron

Question 31

Select the urea cycle reactions that occur in the mitochondria: Ammonia + bicarbonate --> carbamoyl phosphate. Citrulline + aspartate --> argininosuccinate. Ornithine + carbamoyl phosphate --> citrulline. Arginie --> urea + ornithine. Argininosuccinate --> fumarate + arginine

Answer 31

Ornithine + carbamoyl phosphate --> citrulline. Ammonia + bicarbonate --> carbamoyl phosphate

Question 32

The product found by the condensation of oxaloacetate and acetyl CoA is ____.

Answer 32

Citrate

Question 33

What is the statement of chemiosmotic theory?

Answer 33

Energy needed to phosphorylate ADP is provided by the flow of protons down the electrochemical gradient.

Question 34

Which amino acid is the metabolite in the urea cycle, but is not used as a building block of proteins?

Answer 34

Ornithine

Question 35

During sustained exercise, the ATP/AMP ration in muscle cells decreases. What effect does this decreased ATP/AMP ratio have on the activity of glycolysis enzymes phosphofructokinase and pyruvate kinase?

Answer 35

The activity of both enzymes increases due to a lack of allosteric binding of ATP

Question 36

There are 3 major stages in the process of cellular respiration: stage one is [a], stage 2 is [b], and stage 3 is [c].

Answer 36

[a] acetyl-coA production [b] acetyl-coA oxidation (Citric Acid Cycle) [c] electron transfer and oxidative phosphorylation

Question 37

Where does the final step in the generation of free glucose primarily take place?

Answer 37

Endoplasmic reticulum of liver cells