Question 1

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

Accepted Answer

Avery, MacLeod, and McCarty's fractionation and transformation experiment

Question 2

In the Hershey-Chase experiment, what was the significance of using radioactive isotopes $$^{32}P$$ and $$^{35}S$$?

Accepted Answer

To label the protein and DNA components of the bacteriophage, respectively

Question 3

A sample of DNA is found to contain 15% thymine. According to Chargaff’s rules, what percentage of guanine would you expect to find?

Accepted Answer

$$35\%$$

Question 4

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

Accepted Answer

It runs from the 5' end to the 3' end

Question 5

Which of the following is NOT a property required of the genetic material?

Accepted Answer

It must be able to catalyze chemical reactions

Question 6

Which chemical group is found at the 2' position of the sugar in RNA but not in DNA?

Accepted Answer

A hydroxyl group ($$-OH)$$

Question 7

Which of the following base pairs is held together by three hydrogen bonds in the DNA double helix?

Accepted Answer

Guanine–Cytosine

Question 8

What is the main structural difference between purines and pyrimidines?

Accepted Answer

Purines have a double ring, pyrimidines have a single ring

Question 9

Which of the following best explains why UV light at 260 nm is mutagenic to cells?

Accepted Answer

DNA and RNA absorb UV light at this wavelength, causing mutations

Question 10

Which of the following statements about the Watson and Crick model of DNA is FALSE?

Accepted Answer

Adenine pairs with cytosine via two hydrogen bonds

Question 11

If the sequence of one DNA strand is 5'–AGTCTTTA–3', what is the sequence and orientation of the complementary strand?

Accepted Answer

3'–TCAGAAAT–5'

Question 12

Which of the following is a real-world application of the central dogma of molecular biology?

Accepted Answer

Using DNA sequences to produce recombinant insulin in bacteria

Question 13

Which of the following best describes the secondary structure of RNA?

Accepted Answer

Short double-stranded regions formed by complementary base pairing

Question 14

Which of the following is NOT a class of RNA?

Accepted Answer

dRNA

Question 15

Which feature distinguishes Z-DNA from B-DNA?

Accepted Answer

Z-DNA is left-handed and has a zigzag backbone, while B-DNA is right-handed

Question 16

Which of the following best explains why the amount of DNA correlates with the number of chromosome sets in a cell?

Accepted Answer

Each chromosome contains a fixed amount of DNA, so more sets mean more DNA

Question 17

Which of the following is a correct description of a phosphodiester bond in nucleic acids?

Accepted Answer

A bond between the 5' phosphate of one nucleotide and the 3' hydroxyl of another

Question 18

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

Accepted Answer

The 5' end of one strand aligns with the 3' end of the other

Question 19

Which of the following best describes the role of tRNA in protein synthesis?

Accepted Answer

It carries amino acids to the ribosome and matches them to the mRNA template

Question 20

Which experimental result would best support the conclusion that DNA is the genetic material?

Accepted Answer

Transformation of non-virulent bacteria into virulent bacteria by purified DNA

Structure of DNA and RNA: Foundations of Genetic Material

Study Guide - Practice Questions