org chem 19

Essential Organic Chemistry (Bruice)Chapter 19

Essential Organic Chemistry (Bruice)Chapter 19 The Chemistry of Metabolism

1)

Which of the following is incorrect? A)

Animals and humans metabolize compounds in the same way. B)

Chocolate is metabolized as a toxin in dogs. C)

All humans metabolize compounds in the same way. D)

A and B E)

A and C Answer:

E Section: 19.0

2)

Which of the following statements is/are true about metabolism? A)

reactions that living organisms carry out to obtain energy and to synthesize required compounds B)

reactions that organic chemists carry out to obtain energy and to synthesize required compounds C)

reactions that consist of catabolic and anabolic reactions D)

A and C E)

B and C Answer:

D Section: 19.0

3)

Which of the following is not true about catabolic reactions?


A)

Catabolic reactions require NAD+ for a coenzyme. B)

Catabolic reactions are most often oxidation reactions. C)

Catabolic reactions are most often reduction reactions. D)

Catabolic reactions require an oxidizing coenzyme. E)

Catabolic reactions break down complex molecules into simpler ones. Answer:

C Section: 19.0

4)

What are catabolic and anabolic reactions? Answer:

Catabolic reactions are reactions where complex molecules break down into simple molecules and energy.

Anabolic reactions are reactions which require and consume energy in order to convert simple molecules into complex biomolecules.

Section: 19.0

5)

List the four stages of catabolism and briefly explain the significance of each. Answer:

The first stage of catabolism is called digestion. In this stage, fats, carbohydrates, and proteins are hydrolyzed into fatty acids, monosaccharides, and amino acids respectively. The second stage is one in which these hydrolytic products are converted into compounds which can enter the citric acid cycle (acetyl-CoA, pyruvate, citric acid cycle intermediates). The third stage of catabolism is the citric acid cycle itself. For every acetyl-CoA that enters the cycle, two molecules of carbon dioxide are formed. The final stage of catabolism is called oxidative phosphorylation. Herein, every NADH that was formed in the earlier stages is converted into three ATPs.

Section: 19.0

6)

Which of the following statements is/are true about metabolism? A)

reactions that living organisms carry out to obtain energy and to synthesize required compounds


B)

reactions that organic chemists carry out to obtain energy and to synthesize required compounds C)

reactions that consist of catabolic and anabolic reactions D)

A and C E)

B and C Answer:

D Section: 19.0

7)

Describe digestion. Answer:

During digestion the foods consumed are hydrolyzed to different compounds. Fats are hydrolyzed to fatty acids. Carbohydrates are hydrolyzed to monosaccharides. Proteins are hydrolyzed to amino acids.

Section: 19.1

8)

List the four stages of catabolism. Answer:

1. digestion2. conversion of fatty acids, monosaccharides, and amino acids to compounds that can

enter the citric cycle3. the citric acid cycle4. oxidative phosphorylation

Section: 19.1

9)

In a process known as oxidative phosphorylation, every NADH that is formed in carrying out oxidation reactions in the early stages of catabolism is converted into __________.

A)

three ATPs B)

two ATPs C)

four FADHs


D)

six acetyl-CoAs E)

none of the above Answer:

A Section: 19.2

10)

For what compound is ATP an abbreviation? A)

adenine triphosphate B)

adenosine tetraphosphate C)

adenine tetraphosphate D)

adenosine triphosphate E)

adenine triphosphoric acid Answer:

D Section: 19.2

11)

Which of the following statements best explains the source of energy behind the ATP molecule? A)

the energy released when a phosphoanhydride bond of ATP is broken B)

the energy released when adenosine binds to the phosphate C)

the energy released when ribose binds to the phosphate D)

the energy released when adenine binds to ribose E)

the energy released when ATP is reduced Answer


A Section: 19.2

12)

Draw the chemical structure of adenosine triphosphate, (ATP). Answer:

Section: 19.2

13)

Propose a mechanism for the conversion of D-glucose to D-glucose-6-phosphate using ATP as a source of the phosphate.

Answer:

Section: 19.2

14)

What is the name of the compound that catalyzes the reaction of glycerol with ATP to form glycerol-3-phosphate?

Answer:


glycerol kinase Section: 19.3

15)

What is the function of a kinase? Answer:

A kinase is an enzyme that puts a phosphoryl group on its substrate. Section: 19.3


16)

Which of the enzymes below catalyze -oxidation?

I. glycerol-3-phosphate dehydrogenaseII. acyl-CoA dehydrogenase

III. -ketoacyl-CoA thiolaseIV. glycerol kinaseV. enoyl-CoA hydratase

VI. hexokinaseVII. aldolase

VIII. pyruvate kinaseIX. enolaseX. phosphoglyceromutase

XI. 3-L-hydroxyacyl-CoA dehydrogenase A)

IV, VII, VIII, X B)

I, III, IV, VI C)

II, III, V, XI D)

II, V, IX, X E)

I, III, VI, VIII Answer:

C Section: 19.3

17)

Which of the following enyzmes are used to catalyze glycolysis?

I. enolaseII. glycerol kinase

III. aldolaseIV. glycerol-3-phosphate dehydrogenaseV. acyl-CoA dehydrogenase

VI. -ketoacyl-CoA thiolaseVII. enoyl-CoA hydratase

VIII. hexokinaseIX. pyruvate kinaseX. phosphoglyceromutase

XI. 3-L-hydroxyacyl-CoA dehydrogenase A)

II, IV, VI, VII, IX B)


I, III, VIII, IX, X C)

I, V, VII, VIII, X D)

III, V, VI, VII, IX E)

II, IV, VII, VIII, X Answer:

B Section: 19.4

18)

Describe the difference between what has happens to pyruvate under aerobic versus anaerobic conditions.

Answer:

Under aerobic conditions, pyruvate is converted to acetyl-CoA so it can enter the citric acid cycle. Under anaerobic conditions, pyruvate is reduced to lactate. Under anaerobic conditions in yeast, pyruvate is decarboxylated to acetaldehyde which oxidizes NADH to NAD+.

Section: 19.5


19)

Which of the following enyzmes are used to catalyze citric acid cycle?

I. enolaseII. glycerol kinase

III. aldolaseIV. aconitaseV. acyl-CoA dehydrogenase

VI. citrate synthaseVII. enoyl-CoA hydratase

VIII. hexokinaseIX. pyruvate kinaseX. phosphoglyceromutase

XI. fumaraseXII. NADH

XIII. succinate dehydrogenase A)

I, III, IV, XII B)

III, IV, XII, XIII C)

IV, V, VI, XII D)

IV, VI, XI, XIII E)

II, VI, IX, X Answer:

D Section: 19.6

20)

Explain the results from oxidative phosphorylation. Answer:

Oxidative phosphorylation is the fourth stage of catabolism where each of the three NADH molecules formed from one cycle through the citric acid cycle is converted to three ATPs and each FADH2 is

converted to two ATPs. So NADH is oxidized back to NAD+ and FADH2 is oxidized back to FAD. Section: 19.7

21)

Describe anabolism. Answer:


Anabolism involves the synthesis of fatty acids, monosaccharides, and amino acids from acetyl-CoA, pyruvate, and citric acid intermediates. The products from anabolism are used to form fats, carbohydrates, and proteins.

Section: 19.8

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