Question 1

Which of the following best describes the difference between genotype and phenotype in a bacterial cell?

Accepted Answer

Genotype is the complete set of genes in the genome, while phenotype is the observable traits resulting from gene expression.

Question 2

During DNA replication in prokaryotes, which enzyme is responsible for synthesizing the RNA primer?

Accepted Answer

Primase

Question 3

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 4

A mutation that results in the insertion of a single nucleotide into a coding sequence is most likely to cause:

Accepted Answer

A frameshift mutation

Question 5

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

Accepted Answer

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

Question 6

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

Accepted Answer

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

Question 7

Which of the following is a function of plasmids in prokaryotic cells?

Accepted Answer

They replicate independently and often carry genes for antibiotic resistance or virulence.

Question 8

Which of the following codons is recognized as a start codon for translation in most organisms?

Accepted Answer

$$\mathrm{AUG}$$

Question 9

A bacterial cell is exposed to UV light, resulting in the formation of thymine dimers. Which DNA repair mechanism is most likely to directly reverse this damage?

Accepted Answer

Direct repair

Question 10

Which of the following best describes the process of generalized transduction?

Accepted Answer

Transfer of random DNA segments from a donor to a recipient cell via a bacteriophage.

Question 11

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

Accepted Answer

Lactose inactivates the repressor, allowing transcription of the operon.

Question 12

Which of the following statements about the leading and lagging strands during DNA replication is correct?

Accepted Answer

The leading strand is synthesized continuously, while the lagging strand is synthesized discontinuously as Okazaki fragments.

Question 13

Which of the following is NOT a type of horizontal gene transfer in bacteria?

Accepted Answer

Vertical gene transfer

Question 14

A mutation changes a codon from $$\mathrm{UAC} ($$tyrosine) to $$\mathrm{UAA} ($$stop codon). What type of mutation is this?

Accepted Answer

Nonsense mutation

Question 15

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

Accepted Answer

It carries amino acids to the ribosome and matches them to the mRNA codon via its anticodon.

Question 16

Which of the following is true regarding repressible operons such as the trp operon?

Accepted Answer

They are usually transcribed but can be turned off when the end product is abundant.

Question 17

Which enzyme is responsible for removing RNA primers and filling in the gaps with DNA during replication?

Accepted Answer

DNA polymerase I

Question 18

Which of the following best explains why polyribosomes are advantageous for bacterial cells?

Accepted Answer

They enable simultaneous translation of a single mRNA by multiple ribosomes, increasing protein production efficiency.

Question 19

Which of the following is a real-world example of specialized transduction?

Accepted Answer

Transfer of diphtheria toxin genes between bacteria by a bacteriophage.

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

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