Question 1

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

Accepted Answer

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

Question 2

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

Accepted Answer

DNA polymerase

Question 3

In prokaryotic cells, DNA replication begins at a specific site on the circular chromosome called the origin of replication. What is the significance of this site?

Accepted Answer

It is the location where the double helix is first unwound to allow replication machinery to access the DNA.

Question 4

Which of the following statements about the structure of DNA is correct?

Accepted Answer

The two strands of DNA are antiparallel and held together by hydrogen bonds between complementary bases.

Question 5

A mutation occurs that prevents the formation of Okazaki fragments during DNA replication. Which process would be most directly affected?

Accepted Answer

Synthesis of the lagging strand

Question 6

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

Accepted Answer

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

Question 7

During transcription in prokaryotes, what is the role of the sigma factor?

Accepted Answer

It helps RNA polymerase recognize and bind to the promoter region of DNA.

Question 8

Which of the following is a key difference between DNA replication and transcription?

Accepted Answer

DNA replication copies the entire genome, while transcription copies only specific genes.

Question 9

A scientist is studying a bacterial cell with a mutation in the gene encoding DNA ligase. Which of the following processes would be most directly impaired?

Accepted Answer

Joining of Okazaki fragments on the lagging strand during DNA replication

Question 10

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

Accepted Answer

It brings specific amino acids to the ribosome by matching its anticodon to the codon on mRNA.

Question 11

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

Accepted Answer

$$5' \rightarrow 3'$$

Question 12

A patient is diagnosed with a genetic disorder caused by a mutation in the gene encoding RNA polymerase. Which cellular process would be most directly affected?

Accepted Answer

Transcription

Question 13

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

Accepted Answer

It is redundant, meaning that more than one codon can specify the same amino acid.

Question 14

In the process of DNA replication, which enzyme is responsible for unwinding the DNA double helix?

Accepted Answer

Helicase

Question 15

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

Accepted Answer

DNA polymerase can only synthesize DNA in the $$5' \rightarrow 3'$$ direction, so the lagging strand must be made in short fragments as the replication fork opens.

Question 16

Which of the following is a correct sequence of events during transcription in prokaryotes?

Accepted Answer

Initiation, elongation, termination

Question 17

A researcher is analyzing a prokaryotic genome and finds that it contains both chromosomal DNA and plasmids. Which of the following best describes the role of plasmids?

Accepted Answer

They often carry genes that confer advantageous traits, such as antibiotic resistance.

Question 18

Which of the following best describes the function of the promoter region in a gene?

Accepted Answer

It is the DNA sequence where RNA polymerase binds to initiate transcription.

Question 19

During translation, which molecule acts as the template for the synthesis of polypeptides?

Accepted Answer

mRNA

Question 20

Which of the following statements about prokaryotic and eukaryotic genomes is correct?

Accepted Answer

Prokaryotic genomes are typically organized as a single circular chromosome, while eukaryotic genomes are organized as multiple linear chromosomes.

Microbial Genetics: DNA Structure, Replication, Transcription, and Translation

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