Question 1

Which experiment provided definitive evidence that DNA, not protein, is the genetic material in phages infecting bacteria?

Accepted Answer

Hershey and Chase's experiment using radioactive isotopes

Question 2

According to Chargaff’s rules, if a DNA sample contains 30% adenine, what percentage of guanine would you expect?

Accepted Answer

20%

Question 3

What is the significance of the antiparallel arrangement of DNA strands for replication?

Accepted Answer

It requires DNA polymerase to synthesize the lagging strand in fragments.

Question 4

Which enzyme is responsible for relieving the strain caused by unwinding the DNA double helix during replication?

Accepted Answer

Topoisomerase

Question 5

In the Meselson-Stahl experiment, what result supported the semiconservative model of DNA replication?

Accepted Answer

After one replication, DNA was found at an intermediate density.

Question 6

Which of the following best describes the role of telomeres in eukaryotic chromosomes?

Accepted Answer

They postpone the erosion of genes near the ends of DNA molecules.

Question 7

A mutation occurs during DNA replication. Which process is most likely to correct this error before it becomes permanent?

Accepted Answer

Mismatch repair

Question 8

Which of the following is a correct description of the structure of a nucleosome?

Accepted Answer

DNA wound twice around a core of eight histones

Question 9

During DNA replication, which enzyme synthesizes the RNA primer required for DNA polymerase to begin synthesis?

Accepted Answer

Primase

Question 10

Which chemical reaction occurs when a nucleoside triphosphate is added to a growing DNA strand?

Accepted Answer

Dehydration reaction releasing pyrophosphate

Question 11

If a DNA molecule has the sequence 5'-ATCG-3' on one strand, what is the complementary sequence on the other strand?

Accepted Answer

3'-TAGC-5'

Question 12

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are joined together by DNA ligase.

Question 13

What is the evolutionary significance of mutations in DNA?

Accepted Answer

They are the source of genetic variation for natural selection.

Question 14

Which of the following best explains why DNA polymerase can only add nucleotides to the 3' end of a growing strand?

Accepted Answer

The enzyme's active site is specific for the 3' hydroxyl group.

Question 15

Which of the following is a function of histone proteins in eukaryotic cells?

Accepted Answer

Regulating gene expression through chromatin condensation

Question 16

A patient is exposed to X-rays, which damage their DNA. Which repair mechanism is most likely to fix this damage?

Accepted Answer

Nucleotide excision repair

Question 17

Which of the following statements about bacterial chromosomes is correct?

Accepted Answer

They are circular and found in the nucleoid region.

Question 18

Which process is responsible for the formation of euchromatin and heterochromatin in eukaryotic cells?

Accepted Answer

Chromatin packing and histone modification

Question 19

During DNA replication, what is the role of single-strand binding proteins?

Accepted Answer

They stabilize the unwound parental DNA strands.

Question 20

Which equation represents the relationship between the base pairs in a double-stranded DNA molecule according to Chargaff’s rules?

Accepted Answer

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

Chapter 16: The Molecular Basis of Inheritance – Study Notes

Guida di studio - Domande di pratica