Question 1

An enzyme displays ___ when the enzyme accepts only one specific substrate.

Accepted Answer

A)   absolute specificity
B)   relative specificity
C)   stereospecificity
D)   no specificity

Question 2

Where is the peptide bond located in this dipeptide?

Accepted Answer

A)   the CO-NH joining serine and the valine
B)   the doubly bonded oxygen just left of center between the amino acids
C)   the CH-CO on the top of the serine going to the right
D)   the NH-CH between the serine and valine

Question 3

If an amino acid is in a neutral solution, the form the carboxyl group takes is ___.

Accepted Answer

A)   -CO2-
B)   -CO2H+
C)   -CO2-
D)   -CO2H

Question 4

Which interactions are involved in establishing and holding the three-dimensional structure of a protein?

Accepted Answer

A)   salt bridge and disulfide bonds
B)   hydrogen bonds
C)   hydrophobic effects
D)   all of these choices

Question 5

Draw the dipeptide Asp-Ser and label the peptide bond, the N-terminus, and the C-terminus.

Accepted Answer

The answer of Draw the dipeptide Asp-Ser and label the...

Question 6

Alanine is the only $\alpha$-amino acid that does not have a chiral carbon.

Accepted Answer

A) True 
 B)False

Question 7

Organic compounds that are not polypeptides but are necessary for enzymes to properly function are called ___.

Accepted Answer

A)   substrates
B)   zymogens
C)   active sites
D)   coenzymes

Question 8

Given the following amino acids and their R groups:
glycine (R group is -H) - aspartic acid (R group is -CH2COO-)
cysteine (R group is -CH2SH) - lysine (R group is -(CH2)4NH3+)
Which amino acid is not optically active?

Accepted Answer

Question 9

Catalysts, including enzymes, have the role of

Accepted Answer

A)   changing a nonspontaneous chemical reaction to spontaneous.
B)   lowering the activation energy of a reaction.
C)   heating up the reactants to make the reaction progress faster.
D)   changing the pH to a favorable pH for the reaction to progress.

Question 10

A change in pH usually produces a change in enzyme activity because

Accepted Answer

A)   pH of the environment changes the conformation of the enzyme.
B)   enzyme activity increases at extreme pH values (either acidic or basic) .
C)   enzyme activity is usually least active below its optimum pH.
D)   enzyme activity is most active above its optimum temperature.

Question 11

Shown here is the amino acid glycine at a pH of ___.

Accepted Answer

A)   1
B)   7
C)   14
D)   both 1 and 14

Question 12

Leucine-enkephalin, a pentapeptide, is a naturally occurring pain reliever found in the brain. How many peptide bonds are there in leucine-enkephalin?

Accepted Answer

A)   5
B)   4
C)   6
D)   3

Question 13

What form does isoleucine take at pH 14?

Accepted Answer

A)   
B)   
C)   
D)

Question 14

The peptide bond that connects amino acids in proteins is actually an ___ linkage.

Accepted Answer

A)   amine
B)   amide
C)   ether
D)   ester

Question 15

Which reaction is capable of breaking polypeptides into their component amino acids?

Accepted Answer

A)   hydrogenation (adding hydrogen) 
B)   hydrolysis (adding water) 
C)   dehydrogenation (removing hydrogen) 
D)   dehydration (removing water)

Question 16

A tetrapeptide is given as: Ser-Lys-Ala-Pro. Which of the following statements is true?

Accepted Answer

A)   The serine provided a nitrogen for the peptide bond.
B)   The N-terminus is serine (Ser) .
C)   There are four peptide bonds because there are four amino acids.
D)   The listing should be in alphabetical order.

Question 17

Define the term zymogen. Explain why some enzymes are initially produced as zymogens.

Accepted Answer

A zymogen is an enzyme precurs...

Question 18

Enzymes that only catalyze the reaction of a particular stereoisomer are referred to as ___.

Accepted Answer

The answer of Enzymes that only catalyze the reaction of...

Question 19

Classify each amino acid side chain as (nonpolar, polar-acidic, polar-neutral, or polar-basic.) 
a. glycine __________ 
b. aspartic acid __________
c. cysteine __________ 
c. lysine __________

Accepted Answer

a. nonpolar
b. pola...

Question 20

As in α-helix, and the β-sheet are held together by ___ between amide-N-H and C=O groups.

Accepted Answer

The answer of As in α-helix, and the β-sheet are...

Exam 12: Peptides, Proteins, and Enzymes

Which reaction is capable of breaking polypeptides into their component amino acids?

Correct AnswerverifiedShow Answer

Alanine is the only α\alphaα -amino acid that does not have a chiral carbon.

Correct AnswerverifiedShow Answer

Organic compounds that are not polypeptides but are necessary for enzymes to properly function are called ___.

Correct AnswerverifiedShow Answer

Shown here is the amino acid glycine at a pH of ___.

Correct AnswerverifiedShow Answer

The peptide bond that connects amino acids in proteins is actually an ___ linkage.

Correct AnswerverifiedShow Answer

An enzyme displays ___ when the enzyme accepts only one specific substrate.

Correct AnswerverifiedShow Answer

Enzymes that only catalyze the reaction of a particular stereoisomer are referred to as ___.

Correct AnswerverifiedShow Answer

Where is the peptide bond located in this dipeptide?

Correct AnswerverifiedShow Answer

What form does isoleucine take at pH 14?

Correct AnswerverifiedShow Answer

Given the following amino acids and their R groups: glycine (R group is -H) - aspartic acid (R group is -CH2COO-) cysteine (R group is -CH2SH) - lysine (R group is -(CH2)4NH3+) Which amino acid is not optically active?

Correct AnswerverifiedShow Answer

Define the term zymogen. Explain why some enzymes are initially produced as zymogens.

Correct AnswerverifiedA zymogen is an enzyme precurs...View AnswerShow Answer

A tetrapeptide is given as: Ser-Lys-Ala-Pro. Which of the following statements is true?

Correct AnswerverifiedShow Answer

Catalysts, including enzymes, have the role of

Correct AnswerverifiedShow Answer

A change in pH usually produces a change in enzyme activity because

Correct AnswerverifiedShow Answer

Classify each amino acid side chain as (nonpolar, polar-acidic, polar-neutral, or polar-basic.) a. glycine __________ b. aspartic acid __________ c. cysteine __________ c. lysine __________

Correct Answerverifieda. nonpolar b. pola...View AnswerShow Answer

As in α-helix, and the β-sheet are held together by ___ between amide-N-H and C=O groups.

Correct AnswerverifiedShow Answer

Which interactions are involved in establishing and holding the three-dimensional structure of a protein?

Correct AnswerverifiedShow Answer

If an amino acid is in a neutral solution, the form the carboxyl group takes is ___.

Correct AnswerverifiedShow Answer

Leucine-enkephalin, a pentapeptide, is a naturally occurring pain reliever found in the brain. How many peptide bonds are there in leucine-enkephalin?

Correct AnswerverifiedShow Answer

Draw the dipeptide Asp-Ser and label the peptide bond, the N-terminus, and the C-terminus.

Correct AnswerverifiedShow Answer

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Alanine is the only $\alpha$ -amino acid that does not have a chiral carbon.

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Given the following amino acids and their R groups: glycine (R group is -H) - aspartic acid (R group is -CH₂COO^-) cysteine (R group is -CH₂SH) - lysine (R group is -(CH₂)₄NH₃⁺) Which amino acid is not optically active?

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A zymogen is an enzyme precurs...
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Classify each amino acid side chain as (nonpolar, polar-acidic, polar-neutral, or polar-basic.) a. glycine b. aspartic acid c. cysteine c. lysine

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a. nonpolar
b. pola...
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