Question 1

Which experiment provided the first direct evidence that DNA, and not protein, is the genetic material responsible for heredity?

Accepted Answer

Avery-MacLeod-McCarty Experiment

Question 2

In the Hershey-Chase experiment, why was radioactive phosphorus ($$^{32}P) $$used to label DNA?

Accepted Answer

Because phosphorus is found in DNA but not in proteins

Question 3

According to Chargaff's rules, if a DNA sample contains 35% cytosine, what percentage of adenine does it contain?

Accepted Answer

$$15\%$$

Question 4

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

Accepted Answer

Helicase

Question 5

What is the role of single-strand binding proteins during DNA replication?

Accepted Answer

They prevent the separated DNA strands from re-annealing

Question 6

Which of the following best describes the direction of new DNA synthesis?

Accepted Answer

5' to 3' direction

Question 7

If a DNA strand has the sequence 5'-GATTACA-3', what is the sequence of the complementary strand?

Accepted Answer

3'-CTAATGT-5'

Question 8

Which enzyme removes RNA primers and fills in the gaps with DNA nucleotides during replication?

Accepted Answer

DNA polymerase I

Question 9

Why are Okazaki fragments formed on the lagging strand during DNA replication?

Accepted Answer

Because the lagging strand is synthesized discontinuously away from the replication fork

Question 10

A mutation causes a cell to lose the function of DNA ligase. What is the most likely consequence during DNA replication?

Accepted Answer

Okazaki fragments will not be joined together

Question 11

Which of the following best explains why telomeres are important for eukaryotic chromosomes?

Accepted Answer

They prevent the loss of important genetic information during DNA replication

Question 12

Which enzyme is responsible for relieving the twisting strain ahead of the replication fork?

Accepted Answer

Topoisomerase

Question 13

A patient is exposed to high levels of UV radiation, resulting in the formation of thymine dimers. If these are not repaired, what is the most likely outcome?

Accepted Answer

The DNA helix will be distorted, potentially leading to mutations

Question 14

Which of the following statements about DNA packaging in eukaryotes is correct?

Accepted Answer

DNA is packaged with histones to form nucleosomes

Question 15

Which form of chromatin is most accessible for transcription by RNA polymerase?

Accepted Answer

Euchromatin

Question 16

A scientist finds a cell with highly active telomerase. Which type of cell is this most likely to be?

Accepted Answer

A germ cell or a cancer cell

Question 17

Which of the following best describes the semi-conservative model of DNA replication?

Accepted Answer

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

Question 18

Which enzyme synthesizes short RNA primers needed to start DNA synthesis?

Accepted Answer

Primase

Question 19

If a mutation occurs during DNA replication and is not repaired, what is the most likely long-term consequence?

Accepted Answer

The mutation will be passed on to all daughter cells

Question 20

Which of the following is a real-world example of the importance of DNA repair mechanisms?

Accepted Answer

The prevention of skin cancer by repairing UV-induced thymine dimers

DNA as the Genetic Material: Structure, Replication, and Packaging

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