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

Which of the following best explains why the lagging strand is synthesized discontinuously during DNA replication?

Accepted Answer

DNA polymerase can only synthesize DNA in the 5' to 3' direction, so the lagging strand must be synthesized in short fragments.

Question 4

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

Accepted Answer

Conjugation

Question 5

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

Accepted Answer

Nonsense mutation

Question 6

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

Accepted Answer

Enhancer

Question 7

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

Accepted Answer

The repressor is inactivated, and transcription of the lac operon is turned on.

Question 8

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

Accepted Answer

tRNA brings amino acids to the ribosome and matches them to the codons on mRNA using its anticodon.

Question 9

Which equation correctly represents the direction of DNA strand elongation during replication?

Accepted Answer

$$5' \rightarrow 3'$$

Question 10

A frameshift mutation is most likely caused by:

Accepted Answer

Insertion or deletion of one or two nucleotides

Question 11

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

Accepted Answer

There are 64 possible codons, but only 20 amino acids.

Question 12

During transcription, which enzyme synthesizes RNA from a DNA template?

Accepted Answer

RNA polymerase

Question 13

Which of the following is a function of rRNA in the process of translation?

Accepted Answer

Forms the structural and catalytic core of the ribosome

Question 14

Which type of mutation is LEAST likely to affect the encoded protein?

Accepted Answer

Silent mutation

Question 15

Which of the following mechanisms allows bacteria to acquire new genetic material from the environment?

Accepted Answer

Transformation

Question 16

Which of the following best describes the central dogma of molecular genetics?

Accepted Answer

DNA is transcribed into RNA, which is then translated into protein.

Question 17

Which of the following is TRUE regarding the flow of genetic information in cells?

Accepted Answer

DNA is transcribed into mRNA, which is then translated into protein.

Question 18

Which of the following is a real-world consequence of a frameshift mutation in a gene encoding an essential enzyme?

Accepted Answer

The enzyme is truncated or nonfunctional, potentially leading to disease.

Question 19

Which of the following statements about operons is correct?

Accepted Answer

Operons allow multiple genes to be regulated together under a single promoter.

Question 20

Which of the following is a requirement for transcription of the lac operon?

Accepted Answer

Presence of lactose and absence of glucose

Genetics and Molecular Biology in Microbiology: DNA Structure, Replication, Gene Expression, and Mutations

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