Question 1

Which of the following experiments provided the first direct evidence that DNA, and not protein, is the genetic material responsible for heredity?

Accepted Answer

Hershey and Chase's experiment using radioactive isotopes to label DNA and protein in bacteriophages

Question 2

According to Chargaff’s rules, if a DNA sample contains 24% adenine, what percentage of guanine would you expect to find?

Accepted Answer

$$26\%$$

Question 3

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

Accepted Answer

Its double helix structure with complementary base pairing

Question 4

Why is a GC-rich DNA sequence more stable than an AT-rich sequence of the same length?

Accepted Answer

Guanine and cytosine form three hydrogen bonds, while adenine and thymine form only two

Question 5

Which of the following best describes the antiparallel nature of DNA?

Accepted Answer

The two strands run in opposite directions: one from $$5' to$$ $$3'$$, the other from $$3' to$$ $$5'$$

Question 6

Which component is found in RNA but not in DNA?

Accepted Answer

Uracil

Question 7

A scientist isolates a nucleic acid from a virus and finds it contains 30% adenine, 20% guanine, 20% cytosine, and 30% uracil. What type of nucleic acid is this most likely to be?

Accepted Answer

Single-stranded RNA

Question 8

Which of the following is NOT a requirement for a molecule to serve as genetic material?

Accepted Answer

Ability to catalyze metabolic reactions

Question 9

Which scientist’s work provided the first clear evidence that DNA base composition varies between species, supporting the idea that DNA could be the genetic material?

Accepted Answer

Erwin Chargaff

Question 10

Which of the following best explains why the discovery of the double helix structure of DNA was significant?

Accepted Answer

It explained how genetic information could be copied and passed on

Question 11

If a DNA molecule is composed of 35% cytosine, what is the percentage of adenine?

Accepted Answer

$$15\%$$

Question 12

Which of the following statements about purines and pyrimidines is correct?

Accepted Answer

Purines have two rings, and pyrimidines have one ring

Question 13

Which of the following best describes the role of hydrogen bonds in the DNA double helix?

Accepted Answer

They hold the complementary nitrogenous bases together

Question 14

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

Accepted Answer

The $$3'$$ end of one strand is opposite the $$5'$$ end of the other strand

Question 15

Which of the following best explains why DNA, and not protein, was ultimately accepted as the genetic material?

Accepted Answer

Experiments showed that only DNA could transform non-pathogenic bacteria into pathogenic forms

Question 16

Which of the following is a difference between DNA and RNA?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose

Question 17

A DNA molecule is analyzed and found to contain 27% thymine. According to Chargaff’s rules, what percentage of guanine does it contain?

Accepted Answer

$$23\%$$

Question 18

Which of the following best describes the process of transcription?

Accepted Answer

The synthesis of RNA from a DNA template

Question 19

Which of the following is a real-world application of understanding the molecular basis of inheritance?

Accepted Answer

Developing gene therapies to treat genetic diseases

Question 20

Which of the following best explains why the percentage of adenine always equals the percentage of thymine in double-stranded DNA?

Accepted Answer

Adenine forms two hydrogen bonds with thymine, pairing them together

The Molecular Basis of Inheritance: From Genes to Proteins

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