Question 1

Which level of protein structure is defined by the sequence of amino acids in a polypeptide chain?

Accepted Answer

Primary structure

Question 2

A mutation changes a codon from UAU (tyrosine) to UAA (stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 3

Which of the following best describes the role of R-groups in amino acids?

Accepted Answer

They determine the chemical identity and properties of each amino acid.

Question 4

In the Beadle and Tatum experiment, what was the significance of supplementing minimal medium with specific amino acids?

Accepted Answer

It identified which biosynthetic step was blocked by a mutation.

Question 5

Which of the following mutations is most likely to be inherited by offspring?

Accepted Answer

X-linked mutation in sperm

Question 6

A frameshift mutation is most likely caused by which of the following?

Accepted Answer

Insertion or deletion of a single nucleotide

Question 7

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

Accepted Answer

$$\mathrm{Amino\ acid}_1 + \mathrm{Amino\ acid}_2 \rightarrow \mathrm{Dipeptide} + H_2O$$

Question 8

Which of the following is a consequence of a tautomeric shift during DNA replication?

Accepted Answer

Anomalous base pairing leading to point mutations

Question 9

A patient with phenylketonuria (PKU) cannot metabolize phenylalanine due to a mutation in which type of gene product?

Accepted Answer

Enzyme

Question 10

Which of the following best explains why genetic spores are advantageous in mold genetics experiments?

Accepted Answer

They are haploid, so mutations are directly observable.

Question 11

Which of the following is a transition mutation?

Accepted Answer

$$A \rightarrow G$$

Question 12

What is the main difference between a missense and a silent mutation?

Accepted Answer

Missense changes the amino acid; silent does not.

Question 13

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

Accepted Answer

Association of multiple polypeptide subunits

Question 14

If a mutation in the arg2 gene blocks the conversion of ornithine to citrulline, which supplement would rescue growth on minimal medium?

Accepted Answer

Citrulline

Question 15

Which of the following is NOT a possible outcome of a point mutation?

Accepted Answer

Frameshift

Question 16

Which process is most likely to introduce a spontaneous mutation during DNA replication?

Accepted Answer

Slippage in repeat regions

Question 17

Which of the following best describes the function of tRNA during translation?

Accepted Answer

It brings specific amino acids to the ribosome according to the mRNA codon sequence.

Question 18

A mutation changes the DNA sequence from GAT to GAA. What type of mutation is this?

Accepted Answer

Transition

Question 19

Which of the following is a real-world example of a disease caused by a single gene mutation affecting an enzyme?

Accepted Answer

Phenylketonuria (PKU)

Question 20

Which of the following statements about spontaneous mutations is correct?

Accepted Answer

They can arise from replication errors and tautomeric shifts.

Protein Structure, Gene-Protein Connection, and Mutations in Genetics

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