Question 1

Which of the following best describes the structure of DNA as discovered by Watson and Crick?

Accepted Answer

A double-stranded helix with antiparallel strands

Question 2

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

Accepted Answer

DNA Helicase

Question 3

In the context of DNA replication, what is the primary function of DNA Ligase?

Accepted Answer

Joining Okazaki fragments on the lagging strand

Question 4

Which of the following base pairs is stabilized by three hydrogen bonds in DNA?

Accepted Answer

Cytosine–Guanine

Question 5

What is the significance of Griffith's experiment in the history of genetics?

Accepted Answer

It demonstrated that bacteria can transfer genetic information through transformation

Question 6

Which of the following statements about the central dogma of molecular biology is correct?

Accepted Answer

DNA is transcribed into RNA, which is translated into protein

Question 7

During DNA replication, why is the lagging strand synthesized discontinuously?

Accepted Answer

Because the lagging strand template is oriented 5' to 3', requiring synthesis in short fragments

Question 8

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

Accepted Answer

Amino acid

Question 9

What is the role of topoisomerase (gyrase) in bacterial cells?

Accepted Answer

It supercoils DNA to help pack it into a small volume

Question 10

Which of the following best explains why DNA replication is described as 'semi-conservative'?

Accepted Answer

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

Question 11

A mutation occurs that disables the function of RNAase H in a bacterial cell. What is the most likely consequence during DNA replication?

Accepted Answer

RNA primers are not removed from Okazaki fragments, preventing proper lagging strand synthesis

Question 12

Which of the following is a correct pairing of a purine and a pyrimidine in DNA?

Accepted Answer

Adenine–Thymine

Question 13

Which of the following best describes the directionality of DNA synthesis?

Accepted Answer

It proceeds in the 5' to 3' direction

Question 14

Which of the following is a real-life application of beneficial bacteria in the human body?

Accepted Answer

Synthesizing vitamins and aiding digestion

Question 15

A scientist is studying a DNA molecule and finds that 30% of the bases are adenine. According to base-pairing rules, what percentage of the bases should be thymine?

Accepted Answer

$$30\%$$

Question 16

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand

Question 17

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

Accepted Answer

It synthesizes a short RNA primer to initiate DNA synthesis

Question 18

Which of the following is NOT a location where microorganisms are commonly found in or on the human body?

Accepted Answer

Inside the bones

Question 19

Which of the following bonds connects nucleotides together in a single strand of DNA?

Accepted Answer

Phosphodiester bonds

Question 20

A patient is exposed to a mixture of heat-killed virulent bacteria and live non-virulent bacteria. According to Griffith's experiment, what is the most likely outcome?

Accepted Answer

The non-virulent bacteria will acquire virulence and cause disease

Microbiology and Microbial Genetics: Structure and Function of DNA

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