Question 1

Which experiment provided the first strong evidence that DNA, and not protein, is the genetic material in cells?

Accepted Answer

Hershey and Chase’s bacteriophage labeling experiment

Question 2

Which of the following best describes the structure of a DNA double helix as proposed by Watson and Crick?

Accepted Answer

Two antiparallel strands with sugar-phosphate backbone on the outside and paired bases on the inside

Question 3

Which chemical group is attached to the 3’ carbon of the deoxyribose sugar in DNA?

Accepted Answer

A hydroxyl group (–OH)

Question 4

What is the significance of Chargaff’s rules in understanding DNA structure?

Accepted Answer

They demonstrated that the amount of adenine equals thymine and guanine equals cytosine in DNA

Question 5

Which of the following statements about nucleosomes is correct?

Accepted Answer

A nucleosome consists of 146 base pairs of DNA wrapped around eight histone proteins

Question 6

Which of the following is NOT a difference between DNA and RNA?

Accepted Answer

DNA contains phosphate, RNA does not

Question 7

In the Hershey-Chase experiment, why was $$^{32}P$$ used to label DNA and $$^{35}S$$ used to label protein?

Accepted Answer

DNA contains phosphorus but not sulfur; proteins contain sulfur but not phosphorus

Question 8

Which of the following best explains why DNA is supercoiled in prokaryotic cells?

Accepted Answer

To compact the DNA so it fits inside the cell

Question 9

Which enzyme is responsible for relieving the stress caused by unwinding DNA during replication?

Accepted Answer

Topoisomerase

Question 10

A segment of DNA has the following sequence on one strand: 5’-ATGCCGTA-3’. What is the sequence of the complementary strand?

Accepted Answer

3’-TACGGCAT-5’

Question 11

Which of the following is a correct description of a gene according to the molecular definition?

Accepted Answer

A segment of DNA that contains the information to express a protein

Question 12

Which of the following best describes the outcome of Griffith’s experiment when live R strain and heat-killed S strain were injected into mice?

Accepted Answer

The mouse died and live S bacteria were recovered

Question 13

Which of the following is the correct chemical bond that links nucleotides together in a DNA strand?

Accepted Answer

Phosphodiester bond

Question 14

Which of the following is a purine base found in DNA?

Accepted Answer

Adenine

Question 15

What is the distance between adjacent base pairs in the DNA double helix?

Accepted Answer

$$0.34\ \mathrm{nm}$$

Question 16

Which of the following is true about viral genomes?

Accepted Answer

Viral genomes can be DNA or RNA, single- or double-stranded, circular or linear

Question 17

Which of the following best describes the polarity of a DNA strand?

Accepted Answer

It has a free phosphate at the 5’ end and a free OH at the 3’ end

Question 18

Which of the following is a direct result of the antiparallel orientation of DNA strands?

Accepted Answer

The 5’ to 3’ direction of one strand is opposite to the other

Question 19

Which of the following is a function of telomeres in eukaryotic chromosomes?

Accepted Answer

They protect the ends of chromosomes from degradation

Question 20

Which of the following statements about the major and minor grooves of DNA is correct?

Accepted Answer

The major groove is wider than the minor groove

DNA as the Genetic Material: Discovery, Structure, and Organization

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