Question 1

Which experiment provided the first strong evidence that DNA is the genetic material in bacteria?

Accepted Answer

Griffith's transformation experiment with Streptococcus pneumoniae

Question 2

In the Avery, MacLeod, and McCarty experiment, which treatment prevented transformation of non-lethal R strain into lethal S strain in mice?

Accepted Answer

DNase treatment, which destroys DNA

Question 3

During the Hershey-Chase experiment, radioactive phosphorus ($^{32}P$) was used to label DNA. Where was the radioactivity found after infection of bacteria by phages?

Accepted Answer

Inside the bacterial cells

Question 4

Which of the following best describes the flow of genetic information in eukaryotic cells?

Accepted Answer

DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 5

According to Chargaff's rules, if a DNA molecule contains 30% adenine, what percentage of guanine does it contain?

Accepted Answer

$20\%$

Question 6

Which structural feature of DNA allows for complementary base pairing?

Accepted Answer

Hydrogen bonds between nitrogenous bases

Question 7

A scientist isolates a DNA sample and finds it is right-handed with a wide major groove and narrow minor groove. Which DNA form is most likely present?

Accepted Answer

B-DNA

Question 8

Which enzyme is responsible for interconverting between supercoiled and relaxed states of DNA?

Accepted Answer

Topoisomerase

Question 9

During PCR, what is the purpose of the denaturation step?

Accepted Answer

To separate the two DNA strands by breaking hydrogen bonds

Question 10

Which of the following best explains why eukaryotic DNA is packaged into nucleosomes?

Accepted Answer

To compact DNA and regulate gene expression

Question 11

A mutation causes a histone methyltransferase to be overactive. What is the most likely effect on chromatin structure?

Accepted Answer

Increased DNA packing and reduced gene expression

Question 12

Which of the following is NOT a component of a nucleosome?

Accepted Answer

RNA polymerase

Question 13

If a virus uses reverse transcriptase, what is the direction of information flow?

Accepted Answer

RNA $\rightarrow$ DNA $\rightarrow$ Protein

Question 14

Which of the following best describes the chemical structure of a DNA nucleotide?

Accepted Answer

A deoxyribose sugar, a phosphate group, and a nitrogenous base

Question 15

Which of the following scenarios would result in the death of mice in Griffith's experiment?

Accepted Answer

Injection of heat-killed S strain mixed with living R strain

Question 16

Which base pairs are held together by three hydrogen bonds in DNA?

Accepted Answer

Guanine and Cytosine

Question 17

If a segment of DNA is artificially dehydrated, which form does it most likely adopt?

Accepted Answer

A-DNA

Question 18

Which of the following statements about plasmids is correct?

Accepted Answer

They are small, circular DNA molecules found in bacteria

Question 19

Which process is directly responsible for the synthesis of messenger RNA from DNA?

Accepted Answer

Transcription

Question 20

A cell biologist is studying the packing of DNA in eukaryotic cells. Which structure is formed by DNA wrapped around a histone octamer?

Accepted Answer

Nucleosome

DNA, Chromosomes, and the Structural Basis of Cellular Information

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