Reactions in Biochemistry Exam Questions Ch.10

Test questions for Chapter 10

The Reactions of Organic Functional Groups in Biochemistry

1. Select the choice that correctly classifies vitamins by their solubility.

1. Ascorbic acid, or vitamin C, is a water soluble vitamin. Which of the following interactions is primarily responsible for ascorbic acid’s water solubility?

• 1. dispersion forces
  2. dipole-dipole forces
  3. hydrogen bonding forces
  4. ionic bonding
  5. covalent bonding

1. Which statement about vitamins is NOT true?
   1. Water soluble vitamins are excreted in the urine.
   2. Fat soluble vitamins are stored in fat.
   3. Vitamin C is an example of a water soluble vitamin.
   4. Water soluble vitamins should be replenished daily.
   5. Fat soluble vitamins are readily excreted in the urine.

1. Which statement best describes why vitamin A is soluble in organic solvents but not in water?

Vitamin A

1. Actually, vitamin A is water soluble.
2. The hydroxyl group is hydrophobic in this case.
3. Vitamin A does not contain any hydrophilic groups.
4. The hydrophobic part of the molecule is much larger than the hydrophilic.
5. Vitamin A does not contain any hydrophobic groups.
6. Which of the following is a reason for classifying organic molecules by functional group?
   1. The reactivity of a molecule is determined by the functional groups in a molecule.
   2. Molecules with the same functional group tend to react similarly.
   3. A specific functional group has characteristic reactivity.
   4. You can predict the reactivity of a molecule if you know the functional groups that it contains.
   5. All of the above
7. Which of the following pairs of molecules will react similarly in the presence of an oxidant?

1. Which of the following characteristics is not shared by all combustion reactions?
   1. They occur in multiple steps.
   2. They require oxygen.
   3. They release water and carbon dioxide.
   4. They are exothermic.
   5. They are a type of oxidation-reduction reaction.
2. The following reaction is an example of a(n) ___________ reaction.

CH₄ + 2O₂ → CO₂ + 2H₂O

I. oxidation-reduction

II. acid-Base

III. combustion

a. I only

b. I and II only

c. III only

d. I and III only

e. I, II and III

1. Cellular respiration is an example of a(n) ___________ reaction.

I. oxidation-reduction

II. acid-Base

III. combustion

a. I only

b. I and II only

c. III only

d. I and III only

e. I, II and III

1. Cellular respiration and the combustion of fuel in a car engine are similar in many ways, but they also differ. What is one way in which they are different?
   1. Cellular respiration occurs in many steps and the combustion of fuel in a single step.
   2. Cellular respiration is exothermic and the combustion of fuel is endothermic.
   3. Cellular respiration is endothermic and the combustion of fuel is exothermic.
   4. Cellular respiration is fast and the combustion of fuel is slow.
   5. Cellular respiration requires oxygen and the combustion of fuel does not.
2. An oxidation-reduction reaction is the transfer of
   1. methyl groups.
   2. phosphate groups.
   3. protons.
   4. electrons.
   5. oxygen atoms.
3. In an oxidation-reduction reaction, the species that gains electrons is
   1. oxygen.
   2. oxidized.
   3. hydrogen.
   4. reduced.
   5. carbon.
4. In an oxidation-reduction reaction, the species that loses electrons is
   1. oxygen.
   2. oxidized.
   3. hydrogen.
   4. reduced.
   5. carbon.
5. Which of the following is NOT an example of an oxidation-reduction reaction?
6. CH₃COOH + NH₃ → CH₃COO⁻ + ⁺NH₄
7. CH₃CH₂CH=CH₂ + H₂ → CH₃CH₂CH₂CH₃
8. H₂ + F₂ → 2HF
9. CH₄ + 2O₂ → CO₂ + 2H₂O
10. Cu + 2Ag⁺ → Cu²⁺ + 2Ag
11. Which statement best describes the following reaction?

Fe + Cu²⁺ → Fe²⁺ + Cu

1. In this reaction, both iron and copper are reduced.
2. In this reaction, both iron and copper are oxidized.
3. In this reaction, iron is reduced and copper is oxidized.
4. In this reaction, iron is oxidized and copper is reduced.
5. This is not an oxidation-reduction reaction.
6. Which statement best describes what changes occur over the course of the following oxidation-reduction reaction?

Fe + Cu²⁺ → Fe²⁺ + Cu

1. Two electrons are lost.
2. Iron changes into copper.
3. Iron transfers two electrons to copper.
4. Copper transfers two electrons to iron.
5. Two electrons are gained.
6. In the following reaction, the sulfate ion does not react. What is this ion called?

Fe + CuSO₄ → FeSO₄ + Cu

1. This ion has no special name.
2. It is a reactive ion.
3. It is a spectator ion.
4. It is an explosive ion.
5. It is a nonfunctional ion.
6. Which of the following statements describe the processes that can occur during oxidation?
   • 1. loss of electrons
     2. gain of electrons
     3. loss of oxygens
     4. loss of hydrogens
7. I only
8. II only
9. I and III
10. I and IV
11. II and IV
12. Which of the following statements describe the processes that can occur during reduction?
13. loss of electrons
14. gain of electrons
15. loss of oxygens
16. loss of hydrogens
17. II only
18. I only
19. I and III
20. II and IV
21. II and III
22. What does [O] represent in the following reaction?

1. the oxidizing agent
2. the species that is oxidized
3. the reducing agent
4. the species that is protonated
5. atomic oxygen
6. What does [H] represent in the following reaction?

1. the oxidizing agent
2. the species that is oxidized
3. the reducing agent
4. the species that is protonated
5. atomic hydrogen
6. Is the alkene oxidized or reduced during this reaction and how can you tell?

1. Neither, this is not an oxidation-reduction reaction.
2. The alkene is both oxidized and reduced because this is an oxidation-reduction reaction.
3. The alkene is oxidized because it loses two hydrogens.
4. The alkene is reduced because it loses two hydrogens.
5. The alkene is reduced because it gains two hydrogens.
6. Which statement best describes the following reaction?

CH₃CH=CH₂ + H₂ → CH₃CH₂CH₃

propene

1. In this reaction, both propene and hydrogen are reduced.
2. In this reaction, both propene and hydrogen are oxidized.
3. In this reaction, propene is reduced and hydrogen is oxidized.
4. In this reaction, propene is oxidized and hydrogen is reduced.
5. This is not an oxidation-reduction reaction.
6. Is the ketone oxidized or reduced during this reaction and how can you tell?

1. Neither. This is not an oxidation-reduction reaction.
2. The ketone is both oxidized and reduced because this is an oxidation-reduction reaction.
3. The ketone is oxidized because it loses two hydrogens.
4. The ketone is reduced because it loses two hydrogens.
5. The ketone is reduced because it gains two hydrogens.
6. Is the aldehyde oxidized or reduced during the following reaction, and how can you tell?

1. Neither. This is not an oxidation-reduction reaction.
2. The aldehyde is neither oxidized nor reduced because the number of hydrogens does not change.
3. The aldehyde is oxidized because it loses two hydrogens.
4. The aldehyde is reduced because it loses two hydrogens.
5. The aldehyde is oxidized because it gains an oxygen.
6. Which functional group can be oxidized but not reduced?
   1. an alcohol
   2. an alkane
   3. an alkyne
   4. an alkene
   5. a carboxylic acid
7. Sorbitol is a sweetener often used in chewing gum and diet drinks. It is obtained by the following reaction. Which of the following functional group transformations occur during this reaction?

glucose sorbitol

1. The aldehyde becomes an alcohol.
2. An alcohol becomes an aldehyde.
3. An alcohol disappears.
4. A new aldehyde appears.
5. All of the above
6. Sorbitol is a sweetener often used in chewing gum and diet drinks. It is obtained by the following reaction. Is glucose oxidized or reduced during the reaction?

glucose sorbitol

1. It is oxidized.
2. It is reduced.
3. It is neither oxidized nor reduced.
4. It is both oxidized and reduced.
5. Many different reactions occur.
6. What is the product of the following reaction?

1. Which classification of alcohols can undergo oxidation to yield a ketone?
2. Both primary and secondary alcohols yield ketones when oxidized.
3. Both secondary and tertiary alcohols yield ketones when oxidized.
4. Only primary alcohols yield ketones when oxidized.
5. Only secondary alcohols yield ketones when oxidized.
6. Only tertiary alcohols yield ketones when oxidized.
7. Which classification of alcohols cannot be oxidized and why?
8. tertiary, because they don’t have a hydrogen on the carbon adjacent to the alcohol
9. tertiary, because the alcohol is already attached to four atoms
10. secondary, because they are too hindered by carbons adjacent to the alcohol
11. primary, because they undergo competing reactions in the presence of an oxidant
12. primary, because the reaction takes too much energy

1. What is the product when this compound undergoes oxidation?

a. b. c. d. e.

1. What is the product of the following reduction reaction?

a. b. c. d. e.

1. Which of the following molecules can be oxidized to a carboxylic acid?

a. b. c. d. e.

1. Carbohydrates are molecules that are composed of many oxygen-containing functional groups. Carbohydrates, like other oxygen-containing molecules, can be oxidized in the laboratory. Which of the following choices illustrates the oxidation of mannose, a simple carbohydrate?

1. The reaction of fatty acid A is an example of a(n)

H₂

Pt

A B

1. neutralization.
2. combustion.
3. oxidation.
4. reduction.
5. condensation.
6. Foods that contain the product of the reaction shown below are labeled as

H₂

Pt

1. hydrogenated or partially hydrogenated.
2. fatty.
3. oily.
4. fat free.
5. diet.
6. The following reaction is the hydrogenation of an unsaturated fatty acid. Which of the following choices best describe molecules A and B?

H₂

Pt

1. Both A and B are fats.
2. Both A and B are oils.
3. A is a fat and B is an oil.
4. A is an oil and B is a fat.
5. A is an oil and B is a trans-fat.
6. When unsaturated fatty acids are hydrogenated, an isomerization reaction sometimes occurs producing
   1. saturated fatty acids.
   2. unsaturated fatty acid.
   3. cis-fats.
   4. trans-fats.
   5. carboxylate ions.
7. Which of the following statements describes coenzymes?
   1. They are organic molecules derived from vitamins.
   2. They are only found in bacterial cells.
   3. They are chemically unchanged over the course of a reaction.
   4. They are enzymes.
   5. They are oxidoreductases.
8. What is the purpose of NAD⁺ in the body?
9. It is an oxidizing agent.
10. It is a reducing agent.
11. It donates oxygen.
12. It donates hydrogen.
13. It accepts oxygen.
14. Which vitamin is NAD⁺/NADH produced from in the body?
    1. vitamin C
    2. vitamin D
    3. niacin
    4. vitamin E
    5. biotin
15. Which food is NOT high in niacin?
    1. oranges
    2. anchovies
    3. bran
    4. peanuts
    5. tuna
16. When ethanol is metabolized, it is
    1. synthesized.
    2. oxidized.
    3. anabolized.
    4. substituted.
    5. reduced.
17. The first two steps of ethanol metabolism are shown below. Which molecule is reduced over the course of these reactions?

1. ethanol and acetaldehyde
2. alcohol dehydrogenase and acetaldehyde dehydrogenase
3. ethanol and alcohol dehydrogenase
4. acetic acid
5. NAD⁺
6. What is the purpose of flavin adenine dinucleotide (FAD) in the body?
7. It is an oxidizing agent.
8. It is a reducing agent.
9. It donates oxygen.
10. It donates hydrogen.
11. It accepts oxygen.
12. The following reaction shows the oxidation-reduction reaction of FAD/FADH₂. Which choice correctly identifies each molecule?

A B

1. Which statement describes a difference between FAD/FADH₂ ­and NAD⁺/NADH?
2. FAD/FADH₂ is an enzyme and NAD⁺/NADH is not.
3. FAD/FADH₂ is coenzyme and NAD⁺/NADH is not.
4. FAD/FADH₂ is found in cells of the body and NAD⁺/NADH is not.
5. FAD/FADH₂ is involved in reactions of alkenes and NAD⁺/NADH is involved in reactions of C-O bonds.
6. FAD/FADH₂ and NAD⁺/NADH are identical.
7. The following reaction is an example of a(n)

1. neutralization.
2. combustion.
3. oxidation.
4. reduction.
5. condensation.
6. Which statement best describes what occurs over the course of the following reaction?

1. Two hydrogens are added to acyl-CoA, forming a double bond.
2. Two hydrogens are added to acyl-CoA, breaking a double bond.
3. Two protons are added to acyl-CoA, forming a double bond.
4. Two hydrogens are removed from acyl-CoA, forming a double bond.
5. Two protons are removed from acyl-CoA, forming a double bond.
6. The following reaction occurs in the body. Which of the following reactants is most probably required for this reaction to occur?

1. O₂
2. H₂
3. FAD
4. NAD
5. FADH₂
6. The following reaction is one step in the key metabolic pathway called the TCA (or Krebs) cycle. This reaction is missing a reactant (A) which reacts to form a product (B). What is the identity of A and B?

1. A is NAD⁺ and B is NADH + H⁺.
2. A is FAD and B is FADH₂.
3. A is NADH + H⁺ and B is NAD⁺.
4. A is FADH₂ and B is FAD.
5. Actually, there is no A, but B is H₂.
6. FAD and NAD⁺ are examples of
7. enzymes.
8. coenzymes.
9. vitamins.
10. substrates.
11. inhibitors.
12. What is the role of antioxidants in the body?
    1. to reduce free radicals before they can damage cells
    2. to prevent metabolism from occurring
    3. to make free radicals
    4. to react with coenzymes
    5. All of the above
13. Which of the following species is NOT a free radical?
    1. HO^.
    2. HOO^.
    3. CH₄
    4. O₂^.-
    5. ^.CH₃
14. An antioxidant is a substance that prevents ____________ of other cellular substances.
15. all reduction
16. harmful reduction
17. all oxidation
18. harmful oxidation
19. both oxidation and reduction
20. Which of the following is a free radical?
21. ^.OH
22. HCOO^-
23. 

Vitamin C

1. Mg²⁺
2. O₂
3. Which of the following partial structures is an acyl group?

a. b. c. d. e.

1. Which of the following partial structures is an acetyl group?

a. b. c. d. e.

1. The reaction of a carboxylic acid and an alcohol in the presence of a catalyst produces an ester and a molecule of water. Which of the labeled atoms below are involved in making the molecule of water?

1. a and d
2. b and d
3. b, c, and d
4. a, c, and d
5. c, d, and e
6. Which of the following functional groups is produced when a carboxylic acid and an alcohol react in the presence of a catalyst?
7. an aldehyde
8. an ether
9. a ketone
10. an ester
11. a salt
12. Which of the following statements describe esters?
13. They are fruit flavorings.
14. They are sometimes a component of perfumes.
15. Soap can be made from an ester.
    1. All of these statements describe esters.
    2. Only I describes esters.
    3. I and II describe esters.
    4. I and III describe esters.
    5. II and III describe esters.
16. What is the missing reactant for the following reaction?

a. b. c. d. e.

1. What is the name of the functional group produced by the following reaction?

1. a thioester
2. a sulfur
3. a sulfhydride
4. a thiol
5. a hydrogen sulfide
6. What is the product of the following amidation reaction?

1. What is the product of this esterification reaction?

a. b. c. d. e.

1. What is the product of the following reaction?

a. b. c. d. e.

1. An ester, thioester or amide can all undergo hydrolysis. Which of the following characteristics do these three reactions have in common?
2. All produce water.
3. All produce a carboxylic acid.
4. All require a strong acid to occur.
5. All are very unfavorable.
6. All are very fast reactions.

1. Hydrolysis is an example of an acyl group transfer reaction. To what molecule is an acyl group transferred during this type of reaction?
2. an amine
3. –OH
4. a carboxylic acid
5. a thiol
6. an ether
7. During hydrolysis reactions, like all reactions, some bonds are broken and new ones are formed. Which bonds are broken and which are formed during the following hydrolysis reaction?

1. Broken: a-b only Formed: e-a only
2. Broken: b-c only Formed: b-d only
3. Broken: b-c and d-e Formed: b-d and c-e
4. Broken: a-b and b-c Formed: a-e and c-e
5. Broken: a-b and e-d Formed: a-e and b-d
6. Which amide has a line through the bond that is broken during hydrolysis?

a. b. c. d. e.

1. What is the product of the following hydrolysis reaction between an ester and water?

1. Which of the following is the missing reactant in the reaction below, the hydrolysis of a thioester?

1. Which ester has a line through the bond(s) that is broken during hydrolysis?

a. b. c. d. e.

1. What are the products of the following reaction?

1. After an amide is hydrolyzed, it undergoes further reaction. Which of the following occurs after an amide is hydrolyzed?
2. hydration
3. dehydration
4. an acid-base reaction
5. another hydrolysis
6. condensation
7. An amide is hydrolyzed as is shown in the following reaction. After it is hydrolyzed, it undergoes another reaction. Which of the following choices represent the products of this further reaction?

1. What is the product of the following reaction?

1. Which of the following reactions is used in making soap?

1. Which of the following reactions is the saponification of a fat?

1. Which statement best describes the distinction between a hydration and a dehydration reaction?
2. Hydration requires a carbonyl group and dehydration does not.
3. Hydration is the addition of water and dehydration is the loss of water.
4. Hydration results in breaking bonds and dehydration creates bonds.
5. Hydration is an oxidation and dehydration is a reduction.
6. Hydration and dehydration actually describe the same process.
7. Which statement best describes a similarity between a hydration and a dehydration reaction?
8. They both involve hydrogen.
9. They both involve addition to a double bond.
10. They both result in splitting a molecule.
11. The both result in forming one molecule from two.
12. They both involve water.
13. What type of reaction is this?

1. oxidation
2. reduction
3. combustion
4. hydration
5. dehydration
6. What type of reaction is this?

1. oxidation
2. reduction
3. combustion
4. hydration
5. dehydration
6. Which statement best describes what occurs over the course of the following reaction?

1. A hydrogen is added to carbon d and a hydroxyl group is added to carbon c.
2. A hydrogen is added to carbon c and a hydroxyl group is added to carbon d.
3. A hydroxyl group is added to carbon d.
4. A hydrogen is added to both carbon c and d.
5. A hydrogen and a hydroxyl group are added to both carbon c and d.
6. What is the product of the following reaction?

a. b. c. d. e.

1. What is the product of the following reaction?
2. no reaction
3. 
4. 
5. 
6. 
7. What is the product of the following reaction?

1. no reaction
2. 
3. 
4. 
5. 
6. An individual with phenylketonuria (PKU)
   1. does not metabolize phenylalanine.
   2. metabolizes phenylalanine too rapidly.
   3. metabolizes tyrosine too rapidly.
   4. must consume extraordinary quantities of proteins.
   5. does not metabolize tyrosine.
7. The enzyme that converts phenylalanine to tyrosine is an oxidoreductase that requires BH₄, which is converted to BH₄OH over the course of the reaction. BH₄ is a(n)
   1. enzyme.
   2. protein.
   3. coenzyme.
   4. amino acid.
   5. lipid.
8. When an individual has phenylketonuria (PKU),
   1. their blood tyrosine level is too high.
   2. they do not produce phenylpyruvate.
   3. they cannot produce phenylalanine .
   4. their phenylalanine level can become too high without a restricted diet.
   5. it usually is not possible to diagnose it until late in life.
9. Phenylketonuria (PKU) can be managed through a strict diet which restricts or eliminates
   1. beef.
   2. chicken.
   3. fish.
   4. dairy products.
   5. All of the above