Question 1

Trypsin is a digestive enzyme that hydrolyzes peptide bonds only when the carbonyl group in the amide bond comes from Lys or Arg. What fragments result when the peptide Gly-Lys-Arg-Ala-Ala-Arg is hydrolyzed by trypsin?

Accepted Answer

A)  Gly,Lys,Arg,Ala-Ala,Arg
B)  Gly-Lys,Arg-Ala-Ala,Arg
C)  Gly-Lys,Arg,Ala-Ala,ArgD) A) and C)
E) None of the above

Question 2

The β-pleated sheet arrangement of a protein is favored by amino acids with small side chains.

Accepted Answer

A) True 
 B)False

Question 3

What is the charge on a zwitterion?

Accepted Answer

A)  Positive
B)  Neutral
C)  Negative
D)  The charge or lack of charge varies depending on the amino acid.E) A) and B)
F) A) and C)

Question 4

Amino acids with an additional COOH group in the side chain are classified as acidic amino acids.

Accepted Answer

A) True 
 B)False

Question 5

Based on its name,which compound is an enzyme?

Accepted Answer

A)  Glucose
B)  Triosephosphate isomerase
C)  N-acetyl-D-glucosamine
D)  DihydrofolateE) B) and C)
F) A) and D)

Question 6

What is the one-letter abbreviation of arginine?

Accepted Answer

A)  A
B)  R
C)  P
D)  GE) B) and C)
F) C) and D)

Question 7

Tuftsin is a peptide that stimulate and promotes the destruction of tumor cells. Its primary structure is Thr-Lys-Pro-Arg. Which statement is NOT a valid interpretation of its primary structure?

Accepted Answer

A)  It is a tetrapeptide.
B)  Threonine is the N-terminal amino acid and arginine is the C-terminal amino acid.
C)  The amino group of arginine is not joined to any other amino acid.
D)  The carboxyl group of lysine is joined to the amino group of proline.E) B) and D)
F) All of the above

Question 8

Zwitterions have low melting points and are water-soluble.

Accepted Answer

A) True 
 B)False

Question 9

What is a zymogen?

Accepted Answer

A)  An amino acid with a neutral charge
B)  Inactive precursor of an enzyme
C)  A molecule that causes an enzyme to lose activity
D)  A nonprotein organic molecule needed for an enzyme-catalyzed reaction to occurE) A) and B)
F) All of the above

Question 10

________ proteins are composed of long linear polypeptide chains that are bundled together to form rods or sheets that are insoluble in water and serve structural roles.

Accepted Answer

The answer of ________ proteins are composed of long linear...

Question 11

It is possible for two different proteins to contain the same number and type of amino acids.

Accepted Answer

A) True 
 B)False

Question 12

The pH at which an amino acid exists primarily in its neutral form is called its ________ point.

Accepted Answer

The answer of The pH at which an amino acid...

Question 13

About one half of the 223 amino acid residues in the enzyme trypsin are hydrophobic. Where in the tertiary structure of this globular protein are these residues most likely to be found?

Accepted Answer

A)  At the N-terminal end of the peptide chain.
B)  At the C-terminal end of the peptide chain.
C)  On the exterior surface of the folded protein.
D)  In the interior of the folded protein.E) B) and C)
F) A) and B)

Question 14

The β-pleated sheet forms when two or more peptide chains,called strands,line up side-by-side with the C=O and N-H bonds in the plane of the sheets.

Accepted Answer

A) True 
 B)False

Question 15

What type of intermolecular forces exist between the side chains of serine and asparagine?

Accepted Answer

A)  Electrostatic attraction
B)  London dispersion forces
C)  Hydrogen bond
D)  Disulfide bondE) All of the above
F) C) and D)

Question 16

Which choice is the only amino acid capable of forming a disulfide bond?

Accepted Answer

A)  Methionine
B)  Serine
C)  Arginine
D)  CysteineE) B) and D)
F) A) and B)

Question 17

What is the structure of the dipeptide Ser-Gly?

Accepted Answer

A)   
B)   
C)   
D)   E) B) and C)
F) A) and D)

Question 18

What is the charge on an amino acid at a pH below its pI?

Accepted Answer

A)  Positive
B)  Neutral
C)  Negative
D)  The charge or lack of charge varies depending on the amino acid.E) A) and B)
F) None of the above

Question 19

Amino acids are the building blocks of the body's proteins. Which statement concerning amino acids is false?

Accepted Answer

A)  There are approximately 200 standard amino acids that occur naturally in the proteins of the human body.
B)  Except for when R=H,amino acids are chiral molecules.
C)  The amino acids found in human proteins are "alpha" amino acids.
D)  The properties of amino acids and the proteins they compose are determined by the nature of the side chain groups that are present.E) A) and B)
F) A) and C)

Question 20

Which protein stores O2 in tissues?

Accepted Answer

A)  Keratin
B)  Ferritin
C)  Hemoglobin
D)  MyoglobinE) None of the above
F) A) and B)

Exam 21: Amino Acids,proteins,and Enzymes

What is the structure of the dipeptide Ser-Gly?

Correct AnswerverifiedShow Answer

It is possible for two different proteins to contain the same number and type of amino acids.

Correct AnswerverifiedShow Answer

________ proteins are composed of long linear polypeptide chains that are bundled together to form rods or sheets that are insoluble in water and serve structural roles.

Correct AnswerverifiedShow Answer

Zwitterions have low melting points and are water-soluble.

Correct AnswerverifiedShow Answer

Which protein stores O2 in tissues?

Correct AnswerverifiedShow Answer

Amino acids are the building blocks of the body's proteins. Which statement concerning amino acids is false?

Correct AnswerverifiedShow Answer

What is the charge on an amino acid at a pH below its pI?

Correct AnswerverifiedShow Answer

Trypsin is a digestive enzyme that hydrolyzes peptide bonds only when the carbonyl group in the amide bond comes from Lys or Arg. What fragments result when the peptide Gly-Lys-Arg-Ala-Ala-Arg is hydrolyzed by trypsin?

Correct AnswerverifiedShow Answer

What is the charge on a zwitterion?

Correct AnswerverifiedShow Answer

The pH at which an amino acid exists primarily in its neutral form is called its ________ point.

Correct AnswerverifiedShow Answer

The β-pleated sheet forms when two or more peptide chains,called strands,line up side-by-side with the C=O and N-H bonds in the plane of the sheets.

Correct AnswerverifiedShow Answer

The β-pleated sheet arrangement of a protein is favored by amino acids with small side chains.

Correct AnswerverifiedShow Answer

What type of intermolecular forces exist between the side chains of serine and asparagine?

Correct AnswerverifiedShow Answer

Tuftsin is a peptide that stimulate and promotes the destruction of tumor cells. Its primary structure is Thr-Lys-Pro-Arg. Which statement is NOT a valid interpretation of its primary structure?

Correct AnswerverifiedShow Answer

Amino acids with an additional COOH group in the side chain are classified as acidic amino acids.

Correct AnswerverifiedShow Answer

Based on its name,which compound is an enzyme?

Correct AnswerverifiedShow Answer

What is the one-letter abbreviation of arginine?

Correct AnswerverifiedShow Answer

About one half of the 223 amino acid residues in the enzyme trypsin are hydrophobic. Where in the tertiary structure of this globular protein are these residues most likely to be found?

Correct AnswerverifiedShow Answer

Which choice is the only amino acid capable of forming a disulfide bond?

Correct AnswerverifiedShow Answer

What is a zymogen?

Correct AnswerverifiedShow Answer

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Which protein stores O₂ in tissues?

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