Question 1

Which type of bonding is primarily responsible for the formation of alpha helices and beta pleated sheets in the secondary structure of proteins?

Accepted Answer

Hydrogen bonding between the polypeptide backbone constituents

Question 2

A mutation changes a glutamic acid residue to a valine residue in the beta subunit of hemoglobin. Which property change is most responsible for the altered function seen in sickle cell disease?

Accepted Answer

A change from a hydrophilic to a hydrophobic side chain

Question 3

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

Accepted Answer

The association of two or more polypeptide subunits into a functional protein

Question 4

Which of the following interactions is the strongest and most difficult to disrupt in the tertiary structure of a protein?

Accepted Answer

Disulfide bridges

Question 5

A protein is exposed to high heat and extreme pH, causing it to lose its functional shape but not its primary sequence. What is this process called?

Accepted Answer

Denaturation

Question 6

Which experimental technique is commonly used to determine the three-dimensional structure of a protein at atomic resolution?

Accepted Answer

X-ray crystallography

Question 7

Which of the following statements about DNA and RNA is correct?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose as their pentose sugar.

Question 8

Which of the following best describes the backbone of a nucleic acid polymer?

Accepted Answer

Alternating sugars and phosphate groups

Question 9

What type of bond links nucleotides together in a single strand of DNA or RNA?

Accepted Answer

Phosphodiester bond

Question 10

Which of the following base pairs is stabilized by three hydrogen bonds in DNA?

Accepted Answer

Cytosine–Guanine

Question 11

A scientist isolates a nucleic acid and finds that it contains uracil, a ribose sugar, and is single-stranded. Which molecule is it most likely to be?

Accepted Answer

RNA

Question 12

Which of the following changes would most likely disrupt an ionic bond in the tertiary structure of a protein?

Accepted Answer

A change in pH that neutralizes a charged side chain

Question 13

Which of the following is a direct result of the antiparallel orientation of DNA strands?

Accepted Answer

Complementary base pairing occurs between the two strands

Question 14

Which of the following best explains why sickle cell hemoglobin aggregates into fibers while normal hemoglobin does not?

Accepted Answer

A hydrophobic amino acid replaces a hydrophilic one, causing abnormal interactions between hemoglobin molecules

Question 15

Which of the following is true regarding the process of denaturation and renaturation of proteins?

Accepted Answer

Renaturation is sometimes possible if the primary structure remains intact

Question 16

Which of the following is a purine found in both DNA and RNA?

Accepted Answer

Adenine

Question 17

Which of the following best describes the directionality of nucleic acid synthesis?

Accepted Answer

Nucleotides are added to the 3' end, synthesizing from 5' to 3'

Question 18

Which of the following is a correct statement about ATP (adenosine triphosphate)?

Accepted Answer

ATP is a nucleotide composed of adenine, ribose, and three phosphate groups

Question 19

Which of the following is a pyrimidine found only in RNA?

Accepted Answer

Uracil

Question 20

Which of the following best explains why the nitrogenous bases of DNA are located on the inside of the double helix?

Accepted Answer

They are hydrophobic and stack to minimize exposure to water

Bio 100 Lec Chapter 5 Part 3

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