Question 1

Which of the following best describes the structure of a nucleotide in DNA?

Accepted Answer

A nitrogenous base attached to a pentose sugar and a phosphate group

Question 2

In DNA, which base pairing is correct according to the rules of complementation?

Accepted Answer

A pairs with T, and G pairs with C

Question 3

Which type of mutation involves the replacement of a purine with another purine?

Accepted Answer

Transition

Question 4

A patient is exposed to UV radiation, which leads to the formation of pyrimidine dimers in their DNA. Which DNA repair mechanism is most likely to be activated?

Accepted Answer

Nucleotide excision repair (NER)

Question 5

Which of the following equations correctly represents the synthesis of RNA from a DNA template?

Accepted Answer

$$\mathrm{n(NTP)} + \mathrm{DNA} \longrightarrow \mathrm{(NMP)}_n + n(\mathrm{PP_i})$$

Question 6

Which RNA type is responsible for carrying amino acids to the ribosome during translation?

Accepted Answer

Transfer RNA (tRNA)

Question 7

A mutation causes a cytosine to be replaced by a thymine in a DNA sequence. What type of mutation is this?

Accepted Answer

Transition

Question 8

Which of the following is a consequence of a frameshift mutation?

Accepted Answer

Alteration of the reading frame, potentially changing all downstream amino acids

Question 9

During transcription in prokaryotes, which region of the DNA does RNA polymerase bind to first?

Accepted Answer

Promoter

Question 10

Which of the following is a function of the poly-A tail added to eukaryotic mRNA?

Accepted Answer

Protection from degradation and facilitation of export from the nucleus

Question 11

A patient with a defect in the gene encoding a glycosylase enzyme is most likely to have problems with which DNA repair pathway?

Accepted Answer

Base excision repair

Question 12

Which of the following statements about RNA splicing is correct?

Accepted Answer

Alternative splicing allows a single gene to produce multiple protein variants

Question 13

Which of the following is a direct result of UV radiation on DNA?

Accepted Answer

Formation of pyrimidine dimers

Question 14

Which process repairs double-stranded breaks in DNA using homologous chromosomes as templates?

Accepted Answer

Homologous recombination

Question 15

In eukaryotic transcription, which sequence is typically found about 25-35 bases upstream of the transcription start site and is crucial for initiation?

Accepted Answer

TATA box

Question 16

Which of the following best explains why RNA is typically single-stranded while DNA is double-stranded?

Accepted Answer

RNA does not follow strict base pairing rules and is complementary to only one DNA strand

Question 17

A mutation in the BRCA1 gene impairs the repair of double-stranded DNA breaks. Which repair pathway is most affected?

Accepted Answer

Homologous recombination

Question 18

Which of the following is a regulatory RNA involved in gene silencing?

Accepted Answer

miRNA

Question 19

Which of the following is a correct description of a transversion mutation?

Accepted Answer

A purine is replaced by a pyrimidine or vice versa

Question 20

Which of the following is a direct function of ribosomal RNA (rRNA)?

Accepted Answer

Catalyzing peptide bond formation during translation

Genetics Test III Study Guide: DNA/RNA Structure, Gene Mutation & Repair, and Transcription

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