Question 1

Which of the following experiments provided the most direct evidence that DNA, and not protein, is the hereditary material in bacteriophages?

Accepted Answer

Hershey and Chase’s radioactive labeling of phage DNA and protein

Question 2

Which property of DNA allows it to serve as a template for its own replication?

Accepted Answer

Its antiparallel and complementary base pairing

Question 3

A DNA molecule is analyzed and found to contain 30% adenine. According to Chargaff’s rules, what percentage of guanine would you expect?

Accepted Answer

$$20\%$$

Question 4

Which enzyme is responsible for relieving torsional stress ahead of the replication fork during DNA replication?

Accepted Answer

Topoisomerase

Question 5

In the Meselson-Stahl experiment, after two rounds of replication in $$^{14}N$$ medium, what proportion of DNA molecules are expected to be 'light' ($$^{14}N$$/^{14}$$N$$)?

Accepted Answer

Half the molecules

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, while the lagging strand is synthesized in Okazaki fragments.

Question 7

Which of the following is a function of DNA polymerase I in E. coli?

Accepted Answer

Removing RNA primers and replacing them with DNA

Question 8

Which feature of DNA structure is essential for the formation of major and minor grooves?

Accepted Answer

The base-pair stacking and helical twist

Question 9

A mutation in the gene encoding primase would most directly affect which step of DNA replication?

Accepted Answer

Synthesis of RNA primers

Question 10

Which of the following statements about telomerase is correct?

Accepted Answer

It uses an RNA template to extend telomeres

Question 11

Which DNA form is most commonly found in living cells and has a right-handed helix with a diameter of $$20\ 	ext{\AA}$$?

Accepted Answer

B-DNA

Question 12

Which of the following best explains why DNA polymerase has a low error rate during replication?

Accepted Answer

It has 3' to 5' exonuclease proofreading activity

Question 13

Which of the following is a consensus sequence found at the origin of replication in E. coli?

Accepted Answer

TTATCCACA

Question 14

Which of the following is a direct consequence of the antiparallel nature of DNA strands?

Accepted Answer

One strand is synthesized continuously and the other discontinuously

Question 15

Which of the following best describes the role of single-stranded binding proteins (SSB) during DNA replication?

Accepted Answer

They prevent reannealing of separated DNA strands

Question 16

A researcher mutates the DnaA protein in E. coli. Which process will be most directly affected?

Accepted Answer

Binding to the 9-mer sequences at oriC

Question 17

Which of the following is a real-world implication of telomerase activation in human cells?

Accepted Answer

It is associated with increased cell longevity and is active in most cancer cells

Question 18

Which of the following statements about Okazaki fragments is correct?

Accepted Answer

They are joined together by DNA ligase

Question 19

Which of the following best describes the function of the 13-mer and 9-mer sequences at the E. coli origin of replication (oriC)?

Accepted Answer

They are consensus sequences that recruit replication initiation proteins

Question 20

Which of the following is a key difference between bacterial and eukaryotic DNA replication origins?

Accepted Answer

Bacteria have a single origin per chromosome, while eukaryotes have multiple origins

DNA Structure and Replication: Study Notes for Genetics Students 7

Guida di studio - Domande di pratica

Study guide - Flashcard