Question 1

Which of the following best describes a hydrophobic interaction in the context of protein structure?

Accepted Answer

An interaction between nonpolar amino acid side chains that drives them away from water.

Question 2

What is the approximate length of one turn of the DNA double helix?

Accepted Answer

$$3.4\ nm$$

Question 3

Which of the following is NOT a component of a nucleotide in DNA?

Accepted Answer

Amino group

Question 4

If a DNA molecule contains 20% adenine, what percentage of guanine does it contain?

Accepted Answer

$$30\%$$

Question 5

Which type of RNA is directly involved in carrying amino acids to the ribosome during protein synthesis?

Accepted Answer

tRNA (transfer RNA)

Question 6

Which amino acid is always the first in a newly synthesized polypeptide chain in eukaryotes?

Accepted Answer

Methionine

Question 7

What type of bond is primarily responsible for stabilizing the secondary structure of proteins (such as alpha helices and beta sheets)?

Accepted Answer

Hydrogen bonds

Question 8

Which of the following is a correct description of a donor-acceptor covalent bond?

Accepted Answer

A bond where both electrons come from the same atom.

Question 9

Which of the following amino acids is classified as aromatic?

Accepted Answer

Phenylalanine

Question 10

A protein is found to have a pI (isoelectric point) of 9.0. In which type of environment will this protein carry a net negative charge?

Accepted Answer

At pH $$\u003e 9.0$$

Question 11

Which of the following is a post-translational modification that can occur in proteins?

Accepted Answer

Phosphorylation

Question 12

Which of the following best explains why DNA is more stable than RNA under alkaline conditions?

Accepted Answer

DNA lacks the 2'-hydroxyl group present in RNA, preventing base-catalyzed hydrolysis.

Question 13

Which of the following is a correct statement about the primary structure of a protein?

Accepted Answer

It is determined by the sequence of amino acids linked by peptide bonds.

Question 14

Which of the following is a macroelement essential for organic molecules in living organisms?

Accepted Answer

Carbon

Question 15

Which of the following is a correct pairing of a nitrogenous base with its complementary base in DNA?

Accepted Answer

Adenine with Thymine

Question 16

Which of the following is a correct description of a peptide bond?

Accepted Answer

A covalent bond formed between the carboxyl group of one amino acid and the amino group of another.

Question 17

Which of the following is a correct statement about the secondary structure of proteins?

Accepted Answer

It is stabilized by hydrogen bonds between backbone atoms.

Question 18

Which of the following is a correct description of the role of tRNA in translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches its anticodon to the mRNA codon.

Question 19

Which of the following is a correct statement about the tertiary structure of proteins?

Accepted Answer

It is the overall 3D shape of a single polypeptide chain.

Macromolecules, Nucleic Acids, and Proteins: Structure and Function

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