Question 1

Which statement best describes the semiconservative model of DNA replication?

Accepted Answer

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

Question 2

During DNA replication in E. coli, which enzyme is responsible for synthesizing short RNA primers on the single-stranded template?

Accepted Answer

DNA primase (DnaG)

Question 3

What is the primary function of single-stranded binding proteins (SSB) during DNA replication?

Accepted Answer

They prevent separated DNA strands from re-annealing or forming secondary structures.

Question 4

Which DNA polymerase in E. coli is primarily responsible for the bulk of DNA synthesis during replication?

Accepted Answer

DNA polymerase III

Question 5

A mutation in the DnaA protein would most likely affect which step of DNA replication in prokaryotes?

Accepted Answer

Recognition and unwinding of the origin of replication

Question 6

Which of the following best explains why DNA polymerases require a primer to initiate synthesis?

Accepted Answer

DNA polymerases can only add nucleotides to an existing 3' hydroxyl group.

Question 7

In the DNA synthesis reaction, which chemical bond is formed between the incoming nucleotide and the growing DNA strand?

Accepted Answer

Phosphodiester bond

Question 8

Which activity allows DNA polymerase to remove incorrectly paired nucleotides during replication?

Accepted Answer

3' to 5' exonuclease activity

Question 9

A researcher is studying a mutant E. coli strain that cannot remove RNA primers from Okazaki fragments. Which enzyme is most likely defective?

Accepted Answer

DNA polymerase I

Question 10

Which of the following equations correctly represents the release of pyrophosphate during DNA synthesis?

Accepted Answer

$$dNTP + (DNA)_{n} \rightarrow (DNA)_{n+1} + PP_i$$

Question 11

Which feature distinguishes eukaryotic DNA replication from prokaryotic DNA replication?

Accepted Answer

Eukaryotes have multiple origins of replication per chromosome.

Question 12

In a DNA replication experiment, a scientist observes that the newly synthesized DNA contains both parental and new strands. Which model of replication does this support?

Accepted Answer

Semiconservative

Question 13

What is the consensus sequence for the 13-mer at the origin of replication in E. coli?

Accepted Answer

$$TATTTATTTTTT$$

Question 14

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

Accepted Answer

Helicase

Question 15

A patient has a genetic disorder caused by frequent errors in DNA replication. Which DNA polymerase activity is most likely impaired?

Accepted Answer

3' to 5' exonuclease (proofreading) activity

Question 16

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

Accepted Answer

DNA is synthesized in the 5' to 3' direction.

Question 17

Which protein recognizes and binds to the origin of replication in E. coli to initiate DNA replication?

Accepted Answer

DnaA

Question 18

During lagging strand synthesis, which enzyme joins Okazaki fragments together?

Accepted Answer

DNA ligase

Question 19

Which of the following is a real-world consequence of errors in DNA replication that are not corrected by proofreading?

Accepted Answer

Genetic mutations leading to diseases such as cancer

Question 20

If a DNA polymerase lacks 5' to 3' exonuclease activity, which process will be most affected?

Accepted Answer

Removal of RNA primers during DNA replication

DNA Replication: Mechanisms and Enzymes in Prokaryotes and Eukaryotes

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