Question 1

Which of the following best describes the structure of DNA as revealed by the model in the first image?

Accepted Answer

A double helix with antiparallel strands, where the sugar-phosphate backbone is on the outside and nitrogenous bases pair in the center.

Question 2

Which of the following equations correctly represents the number of hydrogen bonds between base pairs in DNA?

Accepted Answer

$$A-T: 2$$ hydrogen bonds; $$G-C: 3$$ hydrogen bonds

Question 3

Which of the following is a pyrimidine base found in both DNA and RNA?

Accepted Answer

Cytosine

Question 4

During DNA replication, which enzyme is primarily responsible for synthesizing the new DNA strand?

Accepted Answer

DNA polymerase

Question 5

Which of the following best explains why the DNA molecule is described as 'antiparallel'?

Accepted Answer

The two strands run in opposite directions: one from 5’ to 3’ and the other from 3’ to 5’.

Question 6

Which of the following is the correct sequence of events in gene expression?

Accepted Answer

Transcription → Translation → Protein synthesis

Question 7

A mutation changes a codon from UAU to UAA. What is the most likely effect on the protein product?

Accepted Answer

The protein will terminate prematurely due to a stop codon.

Question 8

Which of the following antibiotics inhibits the initiation and elongation of peptide synthesis during translation?

Accepted Answer

Streptomycin

Question 9

Which process is illustrated by the transfer of the F factor between bacterial cells via a pilus?

Accepted Answer

Conjugation

Question 10

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

Accepted Answer

It brings specific amino acids to the ribosome according to the mRNA codon.

Question 11

Which of the following is true regarding the difference between prokaryotic and eukaryotic genomes?

Accepted Answer

Eukaryotic genomes are typically larger and contain more genes than prokaryotic genomes.

Question 12

Which of the following is the correct formula for the number of possible codons given four different RNA bases and codons of length three?

Accepted Answer

$$4^3 = 64$

Question 13

Which of the following best describes the process of transformation in bacteria?

Accepted Answer

Uptake of naked DNA fragments from the environment by a recipient cell.

Question 14

Which of the following is a direct product of transcription?

Accepted Answer

mRNA

Question 15

If a DNA template strand has the sequence 3’-TACGGTACG-5’, what is the sequence of the mRNA produced during transcription?

Accepted Answer

5’-AUGCCAUGC-3’

Question 16

Which of the following is NOT a function of proteins encoded by genes?

Accepted Answer

Storing genetic information

Question 17

Which of the following best explains why mutations are important in microbial genetics?

Accepted Answer

They can introduce genetic variation, which may lead to new traits or antibiotic resistance.

Question 18

Which of the following is the correct order of information flow in the central dogma of molecular biology?

Accepted Answer

DNA → RNA → Protein

Question 19

Which of the following codons signals the start of translation in most organisms?

Accepted Answer

AUG

Question 20

Which of the following best describes the effect of tetracycline on bacterial cells?

Accepted Answer

It binds to the ribosome and blocks elongation during translation.

Microbial Genetics: Structure, Function, and Expression of Genetic Material

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