Question 1

Which experiment provided the first strong evidence that DNA, and not protein, is the genetic material in cells?

Accepted Answer

Avery, MacLeod, and McCarty's demonstration that DNA transforms bacteria

Question 2

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

Accepted Answer

A double helix with antiparallel strands and complementary base pairing

Question 3

During DNA replication, which enzyme is responsible for synthesizing the new DNA strand by adding nucleotides to the 3' end?

Accepted Answer

DNA polymerase

Question 4

What is the function of the enzyme helicase during DNA replication?

Accepted Answer

It unwinds the DNA double helix at the replication fork.

Question 5

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 in short fragments.

Question 6

A mutation occurs that disables the proofreading function of DNA polymerase. What is the most likely consequence?

Accepted Answer

The accuracy of DNA replication will decrease, leading to more mutations.

Question 7

Which of the following best defines a replication fork?

Accepted Answer

The Y-shaped region where the parental DNA strands are being unwound

Question 8

If a cell is exposed to UV radiation, which DNA repair mechanism is most likely to be activated to correct the resulting thymine dimers?

Accepted Answer

Nucleotide excision repair

Question 9

Which of the following is a direct result of a mutation in the DNA sequence?

Accepted Answer

A change in the amino acid sequence of a protein

Question 10

Which enzyme is responsible for joining Okazaki fragments on the lagging strand during DNA replication?

Accepted Answer

DNA ligase

Question 11

A scientist is studying a bacterium with a mutation that prevents the formation of RNA primers during DNA replication. Which enzyme is most likely affected?

Accepted Answer

Primase

Question 12

Which of the following equations correctly represents the complementary base pairing in DNA?

Accepted Answer

$$A = T$$ and $$G = C$$

Question 13

During DNA replication, which direction does DNA polymerase synthesize the new strand?

Accepted Answer

5' to 3'

Question 14

Which of the following best explains why Okazaki fragments are formed during DNA replication?

Accepted Answer

DNA polymerase can only add nucleotides to the 3' end, so the lagging strand is synthesized discontinuously.

Question 15

A patient is diagnosed with a genetic disorder caused by a single nucleotide substitution in a gene. What type of mutation is this?

Accepted Answer

Point mutation

Question 16

Which process ensures that errors made during DNA replication are corrected before cell division?

Accepted Answer

Proofreading by DNA polymerase

Question 17

Which of the following is NOT a function of DNA polymerase during replication?

Accepted Answer

Joining Okazaki fragments

Question 18

If the sequence of one DNA strand is 5'-ATCGGCTA-3', what is the sequence of the complementary strand?

Accepted Answer

3'-TAGCCGAT-5'

Question 19

Which of the following best describes a mutation?

Accepted Answer

A permanent change in the nucleotide sequence of DNA

Question 20

A researcher observes that after DNA replication, each new DNA molecule consists of one old strand and one new strand. What is this method of replication called?

Accepted Answer

Semiconservative replication

DNA: The Molecular Basis of Inheritance, Replication, and Repair

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