Question 1

Which of the following best describes the primary structure of a protein?

Accepted Answer

The linear sequence of amino acids in a polypeptide chain.

Question 2

A mutation causes a single amino acid substitution in the hemoglobin protein, resulting in sickle cell disease. This is an example of how changes in which level of protein structure can affect function?

Accepted Answer

Primary structure

Question 3

Which of the following environmental changes is most likely to cause denaturation of a protein?

Accepted Answer

A drastic increase in temperature

Question 4

Which of the following statements about peptide bonds is correct?

Accepted Answer

They are covalent bonds formed by dehydration reactions between the carboxyl group of one amino acid and the amino group of another.

Question 5

Which of the following amino acids would most likely be found in the interior of a globular protein in an aqueous environment?

Accepted Answer

Valine

Question 6

Which technique is most commonly used to determine the three-dimensional structure of a protein?

Accepted Answer

X-ray crystallography

Question 7

Which of the following best explains why proteins can perform such a wide variety of functions in living organisms?

Accepted Answer

Proteins have diverse structures due to the variety of amino acid side chains and their unique sequences.

Question 8

Which of the following is a function of defensive proteins?

Accepted Answer

Protecting against disease by recognizing and binding to foreign molecules

Question 9

A protein loses its biological activity after being exposed to a nonpolar solvent. What is the most likely explanation?

Accepted Answer

The protein was denatured due to disruption of hydrophobic interactions.

Question 10

Which of the following best describes the quaternary structure of a protein?

Accepted Answer

The association of two or more polypeptide chains into a functional protein.

Question 11

Which of the following is true regarding the genetic code and protein synthesis?

Accepted Answer

The sequence of DNA bases in a gene specifies the amino acid sequence of a protein.

Question 12

Which of the following is a difference between DNA and RNA?

Accepted Answer

DNA is usually double-stranded, while RNA is usually single-stranded.

Question 13

Which of the following statements about nucleotides is correct?

Accepted Answer

A nucleotide consists of a nitrogenous base, a five-carbon sugar, and one to three phosphate groups.

Question 14

Which of the following base pairs is found in DNA but not in RNA?

Accepted Answer

Adenine–Thymine

Question 15

A region along one DNA strand has the sequence 5′-TAGGCCT-3′. What is the complementary DNA strand sequence, including the correct 5′ and 3′ ends?

Accepted Answer

3′-ATCCGGA-5′

Question 16

Which of the following diseases is associated with the accumulation of misfolded proteins?

Accepted Answer

Alzheimer’s disease

Question 17

Which of the following best explains why a change in pH can denature a protein?

Accepted Answer

It disrupts hydrogen bonds, ionic bonds, and other weak interactions that stabilize the protein’s structure.

Question 18

Which of the following is a function of receptor proteins?

Accepted Answer

Receiving and responding to chemical signals from outside the cell

Question 19

Which of the following best describes the directionality of a polynucleotide strand?

Accepted Answer

It has a phosphate group at the 5′ end and a hydroxyl group at the 3′ end.

Question 20

Which of the following is a real-life example of protein denaturation?

Accepted Answer

The white of an egg becoming opaque during cooking

Proteins and Nucleic Acids: Structure and Function

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