Question 1

Which experiment provided the first evidence that DNA is the genetic material in cellular life forms?

Accepted Answer

Griffith’s transformation experiment (1928)

Question 2

In the Hershey-Chase experiment, what was the significance of using $$^{32}P$$ and $$^{35}S$$ isotopes?

Accepted Answer

$$^{32}P$$ labeled DNA and $$^{35}S$$ labeled protein, allowing them to distinguish which molecule entered the bacterial cell.

Question 3

Which of the following best describes the Central Dogma of molecular biology?

Accepted Answer

DNA is transcribed into RNA, which is translated into protein.

Question 4

What is the main difference between the organization of prokaryotic and eukaryotic genomes?

Accepted Answer

Prokaryotic DNA is supercoiled with topoisomerases, while eukaryotic DNA is compacted with histone proteins.

Question 5

Which enzyme is responsible for removing RNA primers during DNA replication in E. coli?

Accepted Answer

DNA polymerase I

Question 6

Why is DNA replication described as 'semi-conservative'?

Accepted Answer

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

Question 7

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are short DNA fragments synthesized on the lagging strand.

Question 8

A mutation in the gene encoding DNA ligase would most likely result in which of the following?

Accepted Answer

Failure to join Okazaki fragments on the lagging strand.

Question 9

Which property of DNA polymerase III in E. coli ensures high fidelity during DNA replication?

Accepted Answer

Proofreading activity (3' to 5' exonuclease activity)

Question 10

Why does DNA replication in E. coli initiate at the oriC region?

Accepted Answer

oriC is an AT-rich region that is easier to unwind for replication initiation.

Question 11

Which of the following best explains why the E. coli genome can be compacted 1400-fold within the cell?

Accepted Answer

Supercoiling of DNA by topoisomerase enzymes.

Question 12

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

Accepted Answer

5' to 3' direction

Question 13

Which of the following is a purine base found in DNA?

Accepted Answer

Adenine

Question 14

What is the role of the Tus protein in E. coli DNA replication?

Accepted Answer

It binds to Ter sequences to terminate DNA replication.

Question 15

Which of the following best describes the polarity of a DNA strand?

Accepted Answer

It has a 5' phosphate end and a 3' hydroxyl end.

Question 16

Which of the following is NOT a step in the repetitive processes of macromolecular synthesis?

Accepted Answer

Denaturation

Question 17

If the E. coli genome is $$4 	imes 10^6$ base pairs and each base pair occupies 3.4 angstroms, what is the approximate length of the E. coli chromosome in meters?

Accepted Answer

$$1.4 	imes 10$$^{-3}$$ m

Question 18

Which of the following statements about the lagging strand during DNA replication is correct?

Accepted Answer

It is synthesized discontinuously as Okazaki fragments.

Question 19

Which of the following is a direct result of the Avery, MacLeod, and McCarty experiment?

Accepted Answer

Demonstration that DNA is the transforming principle.

Genomes and Chromosomes: Structure, Function, and Replication in Microbiology

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