Question 1

Which of the following statements best describes the difference between DNA and RNA based on their sugar components?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 2

A scientist is analyzing a nucleic acid sample and finds that it contains uracil, is single-stranded, and has ribose as its sugar. Which type of nucleic acid is this most likely to be?

Accepted Answer

RNA

Question 3

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

Accepted Answer

Nucleic acids are synthesized in the 5' to 3' direction.

Question 4

During the formation of a phosphodiester bond in nucleic acids, which carbons of the ribose sugars are involved in the linkage?

Accepted Answer

The 3' carbon of one ribose and the 5' carbon of the next ribose

Question 5

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

Accepted Answer

A-U

Question 6

A mutation causes a change in the sequence of bases in a DNA molecule. Which level of protein structure is most directly affected by this mutation?

Accepted Answer

Primary structure

Question 7

Which of the following best explains why DNA base pairs can be separated with only a small amount of energy?

Accepted Answer

Base pairs are held together by hydrogen bonds, which are weaker than covalent bonds.

Question 8

Which of the following is a function of proteins that is NOT performed by nucleic acids?

Accepted Answer

Catalyzing chemical reactions as enzymes

Question 9

A protein is found to have a right-handed coil structure stabilized by hydrogen bonds. This structure is best described as:

Accepted Answer

An alpha helix

Question 10

Which of the following amino acids is most likely to be found in the tight turns of a protein due to its small side chain?

Accepted Answer

Glycine

Question 11

Which of the following best describes the process by which amino acids are joined together to form proteins?

Accepted Answer

Condensation reactions forming peptide bonds

Question 12

A researcher is studying a protein that contains several disulfide bridges. Which amino acid is most likely involved in forming these covalent bonds?

Accepted Answer

Cysteine

Question 13

Which of the following statements about the structure of DNA is correct?

Accepted Answer

The two strands are antiparallel and form a right-handed double helix.

Question 14

Which of the following best describes the role of the genome in an organism?

Accepted Answer

The genome is the complete set of DNA in a living organism.

Question 15

A patient has a genetic disorder caused by a mutation in a gene encoding a transport protein. Which of the following is the most likely consequence?

Accepted Answer

The patient may have difficulty moving substances such as oxygen or ions across cell membranes.

Question 16

Which of the following best explains why closely related species have more similar DNA base sequences than distantly related species?

Accepted Answer

Closely related species share a more recent common ancestor, so their DNA has had less time to accumulate differences.

Question 17

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

Accepted Answer

Cytosine pairs with guanine

Question 18

Which of the following best describes the process of gene expression?

Accepted Answer

Gene expression is the transcription and translation of a specific gene to produce a protein.

Question 19

A mutation changes a codon in mRNA from UAC to UAA. What is the most likely effect on the resulting protein?

Accepted Answer

The protein will be shorter due to a premature stop codon.

Question 20

Which of the following best describes the difference between an oligopeptide and a polypeptide?

Accepted Answer

Oligopeptides are short polymers of 20 or fewer amino acids, while polypeptides are longer chains of amino acids.

Nucleic Acids and Proteins: Structure, Function, and Biological Roles

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