Question 1

Which experiment first demonstrated that a 'transforming principle' could transfer heritable traits between bacteria, even though the chemical nature of the principle was not yet known?

Accepted Answer

The Griffith experiment

Question 2

In the classic Griffith experiment, what was the outcome when mice were injected with a mixture of heat-killed S cells and living R cells?

Accepted Answer

The mice died, and living S cells were recovered from their bodies.

Question 3

Avery, MacLeod, and McCarty demonstrated that the 'transforming principle' was DNA by showing that transformation did NOT occur when which molecule was destroyed?

Accepted Answer

DNA

Question 4

In the Hershey-Chase experiment, why was radioactive sulfur ($$^{35}\mathrm{S}) $$used to label proteins but not DNA?

Accepted Answer

Sulfur is found in the amino acids methionine and cysteine, which are present in proteins but not in DNA.

Question 5

What was the key finding from the Hershey-Chase experiment using radioactive phosphorus ($$^{32}\mathrm{P}$$)?

Accepted Answer

Radioactive phosphorus was found inside the bacteria, indicating DNA entered the cells.

Question 6

According to Chargaff’s rules, which of the following relationships is always true for double-stranded DNA?

Accepted Answer

$$[A] = [T]$$

Question 7

Which structural feature of DNA was revealed by Rosalind Franklin’s X-ray diffraction studies?

Accepted Answer

DNA is a double helix with repeating patterns.

Question 8

Why does the Watson-Crick model of DNA require that a purine always pairs with a pyrimidine?

Accepted Answer

To maintain a constant diameter of approximately 2 nm for the double helix.

Question 9

If a DNA molecule is composed of 30% adenine, what percentage of guanine would you expect to find?

Accepted Answer

20%

Question 10

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

Accepted Answer

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

Question 11

Which of the following statements about hydrogen bonding in DNA is correct?

Accepted Answer

Guanine and cytosine are held together by three hydrogen bonds.

Question 12

A scientist isolates DNA from two different species. Species A has 60% GC content, and Species B has 40% GC content. Which species' DNA would require more energy to denature and why?

Accepted Answer

Species A, because GC pairs have more hydrogen bonds.

Question 13

Which of the following best explains why multiple experiments (Griffith, Avery-MacLeod-McCarty, Hershey-Chase) were necessary to confirm DNA as the genetic material?

Accepted Answer

To provide consistent evidence across different organisms and experimental approaches.

Question 14

Which of the following is a direct real-world application of understanding that DNA is the genetic material?

Accepted Answer

Forensic identification using DNA fingerprinting.

Question 15

If a mutation caused a DNA strand to have two purines paired together, what would be the most likely structural consequence?

Accepted Answer

The DNA helix would bulge at the site of the mutation.

Question 16

Which experimental result would most strongly support the conclusion that DNA, and not protein, is the genetic material?

Accepted Answer

Radioactive DNA is found inside bacteria after phage infection.

Question 17

Which of the following best describes the role of the sugar-phosphate backbone in DNA structure?

Accepted Answer

It provides structural support and forms the sides of the DNA ladder.

Question 18

A DNA sample is found to contain 22% thymine. According to Chargaff’s rules, what percentage of cytosine would you expect?

Accepted Answer

28%

Question 19

Which of the following statements about the lytic and lysogenic cycles of bacteriophages is correct?

Accepted Answer

The lysogenic cycle allows viral DNA to be replicated along with the host genome without destroying the host.

Bio 100 LEC Chapter 16 Module 1

스터디 가이드 - 연습 문제

학습 가이드 - 플래시카드