Question 1

Which of the following statements best describes the semiconservative model of DNA replication?

Accepted Answer

Each new DNA molecule consists of one parental strand and one newly synthesized strand.

Question 2

During DNA replication, which enzyme is primarily responsible for synthesizing the new DNA strand by adding nucleotides to the 3' end?

Accepted Answer

DNA polymerase

Question 3

A mutation that changes a codon for an amino acid into a stop codon is called:

Accepted Answer

Nonsense mutation

Question 4

Which of the following best explains why frameshift mutations are often more harmful than point mutations?

Accepted Answer

They change the reading frame, altering all downstream codons.

Question 5

In the lac operon, what happens when lactose is present and glucose is absent?

Accepted Answer

The repressor is inactivated, allowing transcription of the operon.

Question 6

Which of the following is NOT a component of an operon in prokaryotic gene regulation?

Accepted Answer

Enhancer

Question 7

A scientist discovers a bacterial strain that can no longer synthesize proteins. Which molecule is most likely defective?

Accepted Answer

rRNA

Question 8

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

Accepted Answer

It carries amino acids to the ribosome and matches them to the coded mRNA message.

Question 9

If a DNA sequence is 5'-ATGCGT-3', what would be the sequence of the complementary DNA strand?

Accepted Answer

3'-TACGCA-5'

Question 10

Which of the following statements about the genetic code is correct?

Accepted Answer

The genetic code is universal and redundant.

Question 11

A point mutation that does not change the amino acid sequence of a protein is called:

Accepted Answer

Silent mutation

Question 12

Which process involves the transfer of genetic material from one bacterium to another via a bacteriophage?

Accepted Answer

Transduction

Question 13

During transcription, which direction is the RNA strand synthesized?

Accepted Answer

$$5' \rightarrow 3'$$

Question 14

Which of the following best describes horizontal gene transfer in bacteria?

Accepted Answer

Transfer of genes between unrelated individuals of the same generation.

Question 15

A mutation causes the insertion of two nucleotides into a gene. What is the most likely consequence?

Accepted Answer

A frameshift mutation altering all downstream amino acids.

Question 16

Which of the following is a function of the promoter region in an operon?

Accepted Answer

It is the binding site for RNA polymerase to initiate transcription.

Question 17

Which of the following best explains why the leading and lagging strands are synthesized differently during DNA replication?

Accepted Answer

DNA polymerase can only synthesize DNA in the 5' to 3' direction.

Question 18

Which of the following is true about the central dogma of molecular genetics?

Accepted Answer

Information flows from DNA to RNA to protein.

Question 19

A bacterial cell is exposed to a mutagen that causes the deletion of three nucleotides from a gene. What is the most likely effect on the resulting protein?

Accepted Answer

A deletion of one amino acid, but the reading frame is preserved.

Question 20

Which of the following is a real-life example of horizontal gene transfer that can have significant medical consequences?

Accepted Answer

Transfer of antibiotic resistance genes between bacteria via conjugation.

Genetic Material, Gene Transfer, and Gene Regulation in Microbiology

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