Question 1

Which of the following best describes the relationship between genotype and phenotype as illustrated in the central dogma of molecular biology?

Accepted Answer

Genotype refers to the DNA sequence, which is transcribed into mRNA and then translated into proteins that determine phenotype.

Question 2

Which of the following statements about prokaryotic chromosomes is correct?

Accepted Answer

Prokaryotic chromosomes are circular, haploid, and located in the nucleoid region.

Question 3

Which of the following is NOT a function of DNA methylation in bacteria?

Accepted Answer

Direct catalysis of peptide bond formation during translation

Question 4

During DNA replication, which enzyme is responsible for removing RNA primers and replacing them with DNA nucleotides on the lagging strand in bacteria?

Accepted Answer

DNA polymerase I

Question 5

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

The lagging strand is synthesized discontinuously because DNA polymerase can only add nucleotides to the 3' end.

Question 6

Which of the following is a key difference between prokaryotic and eukaryotic mRNA?

Accepted Answer

Eukaryotic mRNA is processed with a 5' cap and poly-A tail, while prokaryotic mRNA is not.

Question 7

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

Accepted Answer

tRNA delivers specific amino acids to the ribosome by matching its anticodon to the codon on mRNA.

Question 8

Which of the following equations correctly represents the directionality of DNA synthesis?

Accepted Answer

$$5' \rightarrow 3'$$

Question 9

A mutation occurs in the gene encoding DNA ligase in a bacterium. Which process would be most directly affected?

Accepted Answer

Joining of Okazaki fragments on the lagging strand during DNA replication

Question 10

Which of the following is true regarding the start codon in translation?

Accepted Answer

The start codon is AUG, which codes for methionine in eukaryotes and formylmethionine in prokaryotes.

Question 11

Which of the following best explains why DNA replication is described as 'semiconservative'?

Accepted Answer

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

Question 12

Which of the following is a function of restriction enzymes in bacteria?

Accepted Answer

They cut foreign DNA at specific sequences, providing defense against bacteriophages.

Question 13

Which of the following is a correct statement about the role of sigma factors in prokaryotic transcription?

Accepted Answer

Sigma factors help RNA polymerase recognize and bind to promoter regions.

Question 14

Which of the following best describes the difference in DNA packaging between eukaryotes and prokaryotes?

Accepted Answer

Eukaryotic DNA is linear and wrapped around histone proteins, while prokaryotic DNA is circular and associated with nonhistone proteins.

Question 15

Which of the following is a unique feature of eukaryotic mRNA processing?

Accepted Answer

Addition of a 5' cap and a poly-A tail

Question 16

Which of the following best explains why DNA polymerase requires a primer to initiate synthesis?

Accepted Answer

DNA polymerase can only add nucleotides to an existing 3' hydroxyl group.

Question 17

Which of the following is true regarding the direction of transcription?

Accepted Answer

RNA polymerase synthesizes RNA in the $$5' \rightarrow 3'$$ direction.

Question 18

A bacterial cell is exposed to a bacteriophage that injects unmethylated DNA. What is the most likely outcome?

Accepted Answer

The bacterial restriction enzymes will degrade the unmethylated viral DNA.

Question 19

Which of the following best describes the role of the Shine-Dalgarno sequence in prokaryotic translation?

Accepted Answer

It is the site where the ribosome binds to initiate translation.

Microbial Genetics: Structure, Replication, and Expression

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