Question 1

Which of the following best describes the process of transformation as discovered by Frederick Griffith?

Accepted Answer

The uptake of external DNA by a cell, resulting in a genetic change

Question 2

In the Hershey-Chase experiment, which element was used to label the viral DNA, and why was this element chosen?

Accepted Answer

Phosphorus, because it is found in DNA but not in protein

Question 3

A scientist analyzes the DNA of a newly discovered organism and finds that 22% of its bases are adenine. According to Chargaff's rules, what percentage of its bases should be guanine?

Accepted Answer

28%

Question 4

Which of the following statements about the structure of DNA is correct?

Accepted Answer

The backbone of DNA is formed by phosphodiester bonds between nucleotides

Question 5

Which experimental result provided the strongest evidence that DNA, and not protein, is the genetic material?

Accepted Answer

Avery, McCarty, and MacLeod's demonstration that only DNA could transform bacteria

Question 6

A biotechnology company wants to introduce a gene for insulin production into bacteria. Which process, first described by Griffith, will they most likely use?

Accepted Answer

Transformation

Question 7

If a DNA sample from a species contains 30% cytosine, what is the expected percentage of thymine in the sample?

Accepted Answer

20%

Question 8

Which of the following best explains why proteins were initially thought to be the genetic material instead of DNA?

Accepted Answer

Proteins have a greater variety of structures and functions than DNA

Question 9

Rosalind Franklin's X-ray diffraction images were critical in determining which feature of DNA?

Accepted Answer

The helical structure of DNA

Question 10

Which of the following statements about base pairing in DNA is correct?

Accepted Answer

Cytosine pairs with guanine via three hydrogen bonds

Question 11

A mutation causes a DNA strand to have 35% guanine. According to Chargaff's rules, what is the expected percentage of cytosine in this DNA?

Accepted Answer

35%

Question 12

Which of the following best describes the directionality of DNA strands in the double helix?

Accepted Answer

One strand runs 5' to 3', the other runs 3' to 5'

Question 13

In the Hershey-Chase experiment, what was the key observation that led to the conclusion that DNA is the genetic material?

Accepted Answer

Radioactive phosphorus was found inside the bacterial cells

Question 14

Which of the following bonds is responsible for linking nucleotides together in a single strand of DNA?

Accepted Answer

Phosphodiester bonds

Question 15

A researcher finds that a DNA sample from a certain species contains 18% thymine. What is the expected percentage of guanine in this DNA?

Accepted Answer

32%

Question 16

Which real-world application relies on the process of transformation as described in the study materials?

Accepted Answer

Using bacteria to produce human insulin

Question 17

Which of the following best explains why the percentages of adenine and thymine are approximately equal in DNA?

Accepted Answer

Adenine pairs with thymine via hydrogen bonds

Question 18

Which feature of DNA allows it to be copied accurately during cell division?

Accepted Answer

The complementary base pairing between strands

Question 19

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

Accepted Answer

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

Question 20

Which historical experiment first demonstrated that a 'transforming principle' could transfer genetic information between organisms?

Accepted Answer

Griffith's experiment with Streptococcus pneumoniae

DNA as Genetic Material: Key Experiments and Structure

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