Question 1

Which experiment provided the strongest evidence that DNA, and not protein, is the genetic material in phages that infect bacteria?

Accepted Answer

Hershey and Chase's experiment using radioactive isotopes to label DNA and protein in T2 phages

Question 2

According to Chargaff’s rules, if a double-stranded DNA molecule contains 18% cytosine, what percentage of adenine would you expect?

Accepted Answer

$$32\%$$

Question 3

Which of the following statements best explains why a purine-purine base pair is not found in the DNA double helix?

Accepted Answer

Purine-purine pairs would result in a double helix that is too wide, inconsistent with X-ray diffraction data.

Question 4

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

Accepted Answer

Topoisomerase

Question 5

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

Accepted Answer

The error rate during DNA replication will increase, leading to more mutations.

Question 6

Which of the following best describes the difference between the leading and lagging strands during DNA replication?

Accepted Answer

The leading strand is synthesized continuously in the 5' to 3' direction, while the lagging strand is synthesized discontinuously as Okazaki fragments.

Question 7

Which enzyme catalyzes the addition of nucleotides to the 3' end of a growing DNA strand during replication?

Accepted Answer

DNA polymerase

Question 8

What is the function of telomerase in eukaryotic cells?

Accepted Answer

It adds repetitive nucleotide sequences to the ends of chromosomes to prevent gene loss during replication.

Question 9

Which of the following is true of heterochromatin but not of euchromatin?

Accepted Answer

It remains tightly coiled at the G1 phase.

Question 10

A scientist is studying a bacterial cell and observes that its DNA is supercoiled and found in a region without a surrounding membrane. What is this region called?

Accepted Answer

Nucleoid

Question 11

Which of the following best describes the structure of a nucleosome?

Accepted Answer

A segment of DNA wound twice around a core of eight histone proteins

Question 12

Which of the following is a direct result of the semiconservative model of DNA replication?

Accepted Answer

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

Question 13

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

Accepted Answer

Adding nucleotides to the 3' end of a growing DNA strand

Question 14

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

Accepted Answer

Nucleotide excision repair

Question 15

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

Accepted Answer

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

Question 16

Which of the following statements about DNA polymerase is correct?

Accepted Answer

It adds nucleotides only to the 3' end of an existing strand.

Question 17

Which of the following is a real-world consequence of mutations that escape DNA repair mechanisms?

Accepted Answer

They can be passed to the next generation and contribute to genetic variation.

Question 18

Which of the following best describes the role of single-strand binding proteins during DNA replication?

Accepted Answer

They stabilize unwound DNA strands and prevent them from reannealing.

Question 19

Which of the following is NOT a feature of the Watson-Crick model of DNA?

Accepted Answer

Base pairs are held together by covalent bonds.

Question 20

Which of the following is a direct result of histone modification in eukaryotic cells?

Accepted Answer

Changes in chromatin condensation and gene expression

ch16 study guide

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드