Question 1

Which of the following best describes the relationship between the structure and function of macromolecules in living organisms?

Accepted Answer

Macromolecular structure and function are inseparable; the three-dimensional structure determines the molecule's function.

Question 2

A patient with sickle-cell disease has a single amino acid substitution in the hemoglobin protein. Which level of protein structure is directly altered by this mutation?

Accepted Answer

Primary structure

Question 3

Which of the following is NOT a function of proteins in living organisms?

Accepted Answer

Storing genetic information

Question 4

Which type of bond is responsible for the primary structure of a protein?

Accepted Answer

Peptide bonds

Question 5

A protein is exposed to high heat and extreme pH, causing it to lose its native structure. What is this process called?

Accepted Answer

Denaturation

Question 6

Which of the following amino acids would most likely be found in the interior of a globular protein, away from water?

Accepted Answer

Valine

Question 7

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

Accepted Answer

It disrupts ionic and hydrogen bonds stabilizing the tertiary and quaternary structures.

Question 8

Which of the following statements about nucleic acids is correct?

Accepted Answer

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

Question 9

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

Accepted Answer

Alternating sugar and phosphate groups

Question 10

A scientist is analyzing a nucleic acid and finds it contains uracil, a ribose sugar, and is single-stranded. What is the identity of this molecule?

Accepted Answer

RNA

Question 11

Which of the following best explains complementary base pairing in DNA?

Accepted Answer

Adenine pairs with thymine, and guanine pairs with cytosine.

Question 12

Which of the following is a correct description of the quaternary structure of a protein?

Accepted Answer

The arrangement and interaction of multiple polypeptide chains in a protein

Question 13

Which of the following is a real-world example of a protein with quaternary structure?

Accepted Answer

Hemoglobin, which consists of two alpha and two beta subunits

Question 14

Which of the following best describes the difference between purines and pyrimidines?

Accepted Answer

Purines have a six-membered ring fused to a five-membered ring, while pyrimidines have a single six-membered ring.

Question 15

Which of the following equations correctly represents the formation of a peptide bond between two amino acids?

Accepted Answer

$$\mathrm{Amino\ acid}_1 + \mathrm{Amino\ acid}_2 \rightarrow \mathrm{Dipeptide} + \mathrm{H}_2\mathrm{O}$$

Question 16

A mutation changes a hydrophobic amino acid to a hydrophilic one in the core of a protein. What is the most likely effect on the protein's structure?

Accepted Answer

The protein may misfold or lose its functional shape.

Question 17

Which of the following best describes the directionality of DNA strands in the double helix?

Accepted Answer

The two strands run antiparallel: one 5' to 3', the other 3' to 5'.

Question 18

Which of the following is a correct statement about the process of protein synthesis in eukaryotic cells?

Accepted Answer

Messenger RNA (mRNA) is synthesized in the nucleus and then transported to the cytoplasm for translation.

Question 19

Which of the following best explains why enzymes are considered biological catalysts?

Accepted Answer

They lower the activation energy of chemical reactions without being permanently changed.

Structure and Function of Macromolecules: Proteins & Nucleic Acids

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