Question 1

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

Accepted Answer

Griffith's experiment with Streptococcus pneumoniae

Question 2

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

Accepted Answer

$$20\%$$

Question 3

Which of the following best describes the structure of DNA as determined by Watson and Crick?

Accepted Answer

A double helix with antiparallel sugar-phosphate backbones and nitrogenous bases paired in the interior

Question 4

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

Accepted Answer

3'-TACGGCAT-5'

Question 5

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

Accepted Answer

Helicase

Question 6

During DNA replication, which strand is synthesized continuously and in the direction of the replication fork?

Accepted Answer

Leading strand

Question 7

What is the function of DNA ligase during DNA replication?

Accepted Answer

Joins Okazaki fragments on the lagging strand

Question 8

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

Accepted Answer

They prevent the loss of essential genes during DNA replication

Question 9

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

Accepted Answer

Increased rate of mutations in the daughter DNA

Question 10

Which of the following statements about the semiconservative model of DNA replication is correct?

Accepted Answer

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

Question 11

Which enzyme relieves the strain caused by the unwinding of the DNA double helix during replication?

Accepted Answer

Topoisomerase

Question 12

In the context of DNA packaging in eukaryotic cells, what is a nucleosome?

Accepted Answer

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

Question 13

Which of the following best describes the difference between euchromatin and heterochromatin?

Accepted Answer

Euchromatin is loosely packed and transcriptionally active, while heterochromatin is highly condensed and inactive

Question 14

Which of the following is a direct result of the antiparallel structure of DNA?

Accepted Answer

DNA polymerase can add nucleotides only to the 3' end

Question 15

A scientist sequences a DNA strand and finds the following sequence: 5'-GCCTAT-3'. What is the complementary sequence?

Accepted Answer

3'-CGGATA-5'

Question 16

Which of the following best explains the evolutionary significance of mutations in DNA?

Accepted Answer

They are the source of genetic variation upon which natural selection acts

Question 17

Which of the following enzymes is responsible for synthesizing the short RNA primer needed to start DNA replication?

Accepted Answer

Primase

Question 18

During nucleotide excision repair, which enzyme removes the damaged segment of DNA?

Accepted Answer

Nuclease

Question 19

Which of the following statements about DNA replication in prokaryotes and eukaryotes is correct?

Accepted Answer

Prokaryotes have a single origin of replication, while eukaryotes have multiple origins

Question 20

A patient has a genetic disorder caused by the loss of essential genes at the ends of chromosomes. Which enzyme is most likely defective in this patient?

Accepted Answer

Telomerase

Chapter 16

Guida di studio - Domande di pratica

Study guide - Flashcard