Q: Which of the following sequences represents the correct flow of genetic information according to the central dogma of molecular biology?

$$\text{DNA} \rightarrow \text{RNA} \rightarrow \text{Protein}$$

Question 1

Which enzyme is responsible for unwinding the DNA double helix during DNA replication?

Accepted Answer

Helicase

Question 2

During transcription, which of the following best describes the direction in which RNA polymerase synthesizes the new RNA strand?

Accepted Answer

5' to 3'

Question 3

A frameshift mutation is most likely to result from which of the following genetic changes?

Accepted Answer

The insertion of two bases

Question 4

Which of the following is NOT a component of a nucleotide in DNA?

Accepted Answer

A ribose sugar

Question 5

Which process is illustrated by the following equation?

$$	ext{DNA} \xrightarrow{	ext{RNA polymerase}} 	ext{RNA}$$

Accepted Answer

Transcription

Question 6

In the lactose operon, what happens when lactose is present in the environment?

Accepted Answer

The repressor is inactivated, allowing RNA polymerase to transcribe the operon.

Question 7

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

Accepted Answer

It brings amino acids to the ribosome and matches them to the mRNA codon.

Question 8

A scientist observes that a bacterial cell has acquired a new trait after exposure to a bacteriophage. Which gene transfer mechanism is most likely responsible?

Accepted Answer

Transduction

Question 9

Which of the following statements about the tryptophan operon is correct?

Accepted Answer

It is repressed by the presence of tryptophan.

Question 10

Which of the following best explains why a frameshift mutation is often more detrimental than a point mutation?

Accepted Answer

It changes the reading frame, potentially altering every amino acid downstream.

Question 11

Which experiment provided direct evidence that DNA is the molecule responsible for transformation in bacteria?

Accepted Answer

Oswald Avery's experiment with purified macromolecules

Question 12

Which of the following sequences represents the correct flow of genetic information according to the central dogma of molecular biology?

Accepted Answer

$$	ext{DNA} ightarrow 	ext{RNA} ightarrow 	ext{Protein}$$

Question 13

Which of the following is a characteristic of semiconservative DNA replication?

Accepted Answer

Each new DNA molecule consists of one old and one new strand.

Question 14

Which of the following is true about the structure of RNA compared to DNA?

Accepted Answer

RNA is usually single-stranded and contains uracil instead of thymine.

Question 15

A bacterial cell is able to take up naked DNA from its environment and incorporate it into its genome. This process is known as:

Accepted Answer

Transformation

Question 16

Which of the following best describes the role of DNA ligase during DNA replication?

Accepted Answer

It seals gaps between Okazaki fragments on the lagging strand.

Question 17

Which of the following is a real-life consequence of a mutation in a gene encoding a metabolic enzyme?

Accepted Answer

The cell may lose the ability to metabolize a specific nutrient, leading to a growth defect.

Question 18

Which of the following is the correct complementary mRNA sequence for the DNA template strand 3'-TACGGTACC-5'?

Accepted Answer

5'-AUGCCAUGG-3'

Question 19

Which of the following best describes the function of the operator region in an operon?

Accepted Answer

It is the binding site for a repressor protein to regulate transcription.

Question 20

A mutation changes the codon UAU (tyrosine) to UAA (stop codon) in an mRNA sequence. What type of mutation is this?

Accepted Answer

Nonsense mutation

Microbial Genetics: Mechanisms of Gene Expression, Mutation, and Gene Transfer

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