Question 1

Which of the following best describes the difference between DNA and RNA in terms of structure and function?

Accepted Answer

DNA is double-stranded with deoxyribose sugar and contains thymine, while RNA is single-stranded with ribose sugar and contains uracil.

Question 2

During DNA replication, which enzyme is responsible for synthesizing short RNA primers required for DNA polymerase to begin synthesis?

Accepted Answer

Primase

Question 3

A mutation changes a codon from UAU (tyrosine) to UAA. What type of mutation is this, and what is its likely effect?

Accepted Answer

Nonsense mutation; introduces a premature stop codon

Question 4

Which of the following best explains why eukaryotic ribosomes are less affected by prokaryotic-targeting antibiotics?

Accepted Answer

Eukaryotic ribosomes are made of different subunits (60S and 40S) and are separated from the cytoplasm by the nuclear membrane.

Question 5

Which of the following is the correct sequence of events in the lytic cycle of a bacteriophage?

Accepted Answer

Attachment, Penetration, Transcription, Replication, Assembly, Release

Question 6

A scientist exposes bacterial cells to UV light, which causes the formation of thymine dimers. What is the most likely consequence of this exposure?

Accepted Answer

Distortion of the DNA helix, leading to errors during DNA replication

Question 7

Given the DNA template strand 5'-ATG CCG TAA-3', what is the corresponding mRNA sequence?

Accepted Answer

$$5'-AUG CCG UAA-3'$$

Question 8

Which of the following best describes the function of the genetic code?

Accepted Answer

It is a collection of codons on mRNA that direct the incorporation of amino acids into a protein during translation.

Question 9

Which of the following is a key difference between generalized and specialized transduction in bacteria?

Accepted Answer

Generalized transduction can transfer any gene from the donor cell, while specialized transduction transfers only specific genes near the prophage integration site.

Question 10

Which of the following best describes the role of intercalating agents in mutagenesis?

Accepted Answer

They increase the frequency of frameshift mutations by inserting between DNA bases and distorting the helix.

Question 11

Which of the following statements about plasmids is correct?

Accepted Answer

Plasmids are small, circular DNA molecules that carry accessory genes separate from the bacterial chromosome.

Question 12

A patient is infected with a virus that has a segmented RNA genome. Which of the following is a likely consequence of this genome structure?

Accepted Answer

The virus can undergo antigenic shift, leading to rapid changes in surface proteins.

Question 13

Which of the following best explains why viruses can only multiply inside cells?

Accepted Answer

Viruses lack the necessary enzymes and ribosomes for protein synthesis and energy production.

Question 14

Which of the following is a function of the CRISPR system in bacteria?

Accepted Answer

It provides adaptive immunity against invading viruses by storing viral DNA sequences.

Question 15

Which of the following is a characteristic of a productive viral infection?

Accepted Answer

The virus replicates and produces new virions, often leading to host cell lysis.

Question 16

Which of the following best describes a frameshift mutation?

Accepted Answer

An insertion or deletion of a gene coding for a different amino acid, often resulting in a premature stop codon

Question 17

Which of the following is true regarding the process of transformation in bacteria?

Accepted Answer

It involves the uptake of naked DNA from the environment by a bacterial cell.

Question 18

Which of the following is a function of the promoter region in gene expression?

Accepted Answer

It is the specific region of a gene where RNA polymerase can bind and initiate transcription.

Question 19

Which of the following is a role of tRNA during translation?

Accepted Answer

tRNA carries amino acids to the ribosome and matches them to the coded mRNA message using its anticodon.

Question 20

Which of the following best describes the function of exons in eukaryotic gene expression?

Accepted Answer

Exons are coding regions that are joined together to form the final mRNA and determine the amino acid sequence of the protein.

Blueprint of Life: DNA, RNA, Microbial Genetics, Fungi, and Viruses – Study Notes

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