Deck 9: DNA Structure and Analysis

Question 1

Regarding the structure of DNA, the covalently arranged combination of a deoxyribose and a nitrogenous base would be called a(n) _.

A) ribonucleotide
B) nucleotide
C) nucleoside
D) monophospate nucleoside
E) oligonucleotide

Answer 1

C

Question 2

In the classic experiment conducted by Hershey and Chase, why was the pellet radioactive in the centrifuge tube that contained bacteria with viruses?

A) The radioactive viruses (coats plus DNA) were in the pellet.
B) The radioactive viruses were in the pellet, and the bacteria were in the supernatant.
C) The bacteria were in the pellet, and they had incorporated radioactive proteins into their cell membranes.
D) The radioactive protein coats of the viruses were in the pellet.
E) The bacteria were in the pellet, and many contained the radioactive viral DNA.

Answer 2

E

Question 3

Present an overview of two classical experiments that demonstrated that DNA is the genetic material. Can RNA be the genetic material? Explain.

Answer 3

(1) Transformation in bacteria (Griffith through Avery et al.); see appropriate
figures in the text. (2) The Hershey and Chase experiment in bacteriophage; see appropriate figures in the text. Yes, RNA can be the genetic material as
described for the Tobacco Mosaic Virus (TMV), retroviruses, and many others.

Question 4

In an analysis of the nucleotide composition of double -stranded DNA to see which bases are equivalent in concentration, which of the following would be true?

A) A + C = G + T
B) A = C
C) A = G and C = T
D) A + T = G + C
E) A = G and C = T and A + C = G + T are both true.

Question 5

The classic Hershey and Chase (1952) experiment that offered evidence in support of DNA being the genetic material in bacteriophages made use of which of the following labeled component(s)?

A) phosphorus and sulfur
B) nitrogen and oxygen
C) hydrogen
D) tritium
E) None of the answers listed is correct.

Question 6

The basic structure of a nucleotide includes _.

A) amino acids
B) phosphorus and sulfur
C) base, sugar, and phosphate
D) mRNA, rRNA, and tRNA
E) phosphorus and zinc

Question 7

Describe four major functions of DNA in a cell.

Question 8

Considering the Central Dogma of Molecular Genetics, what general property is ascribed to DNA?

Question 9

In the 1860s, a Swiss chemist, Friedrick Miescher, isolated an acidic substance from cell nuclei. What was the name of this substance, and what was its significance?

Question 10

Considering the structure of double -stranded DNA, which kind(s) of bonds hold one complementary strand to the other?

A) van der Waals
B) hydrogen
C) hydrophobic and hydrophilic
D) covalent
E) ionic

Question 11

Reverse transcriptase is an enzyme found in association with retroviral activity. It has the property of _.

A) requiring no template
B) synthesis of DNA from an RNA template
C) synthesis of miRNA to cDNA
D) translation
E) synthesis of RNA from a DNA template

Question 12

If 15 percent of the nitrogenous bases in a sample of DNA from a particular organism is thymine, what percentage should be cytosine?

A) 40 percent
B) 35 percent
C) 70 percent
D) 30 percent
E) 15 percent

Question 13

What was the Avery et al.'s (1944) contribution to the understanding of molecular biology?

Question 14

The strongest direct evidence that DNA is the genetic material comes from which contemporary methodology?

Question 15

Beatrice Mintz and others microinjected DNA into a fertilized mouse egg that after
reaching maturity could be transmitted to the mouse's offspring. What is the general term used to describe an organism that incorporates foreign DNA?

Question 16

List two major differences between RNA and DNA at the level of the nucleotide.

Question 17

Briefly define transformation and describe the relationship between the phenomenon of transformation and the discovery that DNA is the genetic material in bacteria.

Question 18

Given the structure below, please answer the following questions. Is the accompanying figure DNA or RNA? ________ Is the arrow closest to the 5' or 3' end? ________ Spleen diesterase is an enzyme that breaks the covalent bond that connects the phosphate to the 5' carbon. Assume that the dinucleotide is digested with spleen diesterase. To which base and to which carbon on the sugar is the phosphate now attached, A or T?

A) RNA; 3' end; A, 3'
B) DNA; 5' end; A, 5'
C) RNA; 3' end; T, 3'
D) DNA; 3' end; A, 3'
E) DNA; 3' end; T, 5'

Question 19

What are the two major components of the Tobacco Mosaic Virus?

A) RNA and DNA
B) RNA and protein
C) lipids and nucleic acids
D) DNA and protein
E) carbohydrates and nucleic acids

Question 20

Experiments conducted in the 1920s by Frederick Griffith involving the bacterium
Diplococcus pneumoniae demonstrated that a substance from one bacterial strain could genetically transform other bacterial strains. What was the name of the substance
capable of such transformation, and who finally determined its identity?

Question 21

Is the accompanying figure DNA or RNA? Is the circle closer to the 5' or 3' end?

Question 22

List three forms of DNA.

Question 23

Explain how and why the following circumstances influence characteristics of temperature -induced DNA melting:
percentage of GC base pairs
urea (forms hydrogen bonds with bases)
sodium chloride (neutralizes negatively charged phosphates)

Question 24

If the GC content of a DNA molecule is 60 percent, what are the molar percentages of the four bases (G, C, T,

A)?

Question 25

What is meant by the term antiparallel?

Question 26

At what approximate wavelengths do DNA, RNA, and proteins maximally absorb light?

Question 27

The transforming principle discovered by Griffith is RNA.

Question 28

Consider the structure of double -stranded DNA. When DNA is placed into distilled water, it denatures; however, by adding NaCl, the DNA renatures. Why?

Question 29

During the polymerization of nucleic acids, covalent bonds are formed between neighboring nucleotides. Which carbons are involved in such bonds?

Question 30

Is the accompanying figure DNA or RNA? Is the circle closer to the 5' or 3' end?

Question 31

Assume that the molar percentage of thymine in a double -stranded DNA is 20. What are the percentages of the four bases (G, C, T,

A)? If the DNA is single -stranded, would you change your answer?

Question 32

What is the difference between a polynucleotide and an oligonucleotide?

Question 33

What does it mean to say that double -stranded nucleic acids are antiparallel?

Question 34

All other factors being equal, the renaturation of the three classes of complementary nucleic acid sequences occurs in what order, from fastest to slowest?

Question 35

Suppose that the dinucleotide in the accompanying figure were cleaved with the
enzyme spleen diesterase, which breaks the covalent bond connecting the phosphate to C -5'. After such cleavage, to which nucleoside is the phosphate now attached?

Question 36

Name the pyrimidines and the purines in DNA.

Question 37

(a) Assume that A + T/G + C equals 0.5 in one strand of DNA. What is the ratio of these bases in the complementary strand? (b) If A + G/T + C equals 0.5 in one strand, what is the ratio of these bases in the complementary strand?

Question 38

The base content of a sample of DNA is as follows: A = 31%, G = 31%, T = 19%, C =
19%. What conclusion can be drawn from this information?

Question 39

Provide an overview of the structure of Z -DNA.

Question 40

What is the name of the precursor molecule used in nucleic acid synthesis?

Question 41

G and C are present in both DNA and RNA.

Question 42

When considering the structure of DNA, we would say that complementary strands are antiparallel.

Question 43

Hershey and Chase used labeled DNA and protein to determine that DNA is the genetic material in bacteria.

Question 44

Deoxyribonuclease is an enzyme that adds 3' -hydroxyl groups to RNA.

Question 45

In RNA, uracil is present instead of the thymine in DNA.

Question 46

Avery et al. (1944) determined that DNA is the genetic material in T2 bacteriophage.

Question 47

In ribose, the 2' -C has an OH attached to it.

Question 48

DNA has no sulfur, and proteins have no phosphorus.

Question 49

In 1953, Watson and Crick published a paper that described the structure of DNA.