Question 1

One of the primary functions of RNA molecules is to ________.

Accepted Answer

A)   transmit genetic information to offspring
B)   function in the synthesis of proteins
C)   make a copy of itself, thus ensuring genetic continuity
D)   act as a pattern or blueprint to form DNA
E)   form the genes of higher organisms B

Question 2

In the acid-base reaction described in the preceding paragraph about Nakano's research on RNAs, a proton (H+)  is being transferred. What is acting as the proton acceptor?

Accepted Answer

A)   cytosine
B)   magnesium hydroxide
C)   the virus
D)   cytosine, magnesium hydroxide, or the virus

Question 3

Which of the following best describes DNA's secondary structure?

Accepted Answer

A)   beta-pleated sheet
B)   double parallel helical strands
C)   turn-loop-turn
D)   double antiparallel helical strands

Question 4

Which of the following did Watson and Crick already know when they were trying to determine the structure of DNA? The number of ________.

Accepted Answer

A)   purines is always larger than the number of pyrimidines
B)   pyrimidines is always larger than purines
C)   cytosines is always the same as adenines
D)   guanines is always the same as thymines
E)   purines is always the same as pyrimidines

Question 5

Why is it that RNA can catalyze reactions but DNA cannot?

Accepted Answer

A)   The sugar of RNA is much more reactive than the sugar of DNA.
B)   The bases of RNA are much more reactive than the bases of DNA.
C)   The phosphate groups of RNA are much more reactive than the phosphate groups of DNA.
D)   The primary structure of RNA is fundamentally different than the primary structure of DNA. A

Question 6

What is the difference between a ribonucleotide and a deoxyribonucleotide?

Accepted Answer

A)   Ribonucleotides contain a phosphate group.
B)   Ribonucleotides have a hydroxyl group on the 2 carbon of their sugar subunit.
C)   Ribonucleotides contain a sugar with five carbon atoms.
D)   Ribonucleotides have a hydrogen atom on the 1 carbon of their sugar subunit.

Question 7

What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed?

Accepted Answer

A)   their methyl groups
B)   their sugar groups
C)   their nitrogenous bases
D)   their phosphate groups

Question 8

What is/are the variable structure(s)  of a nucleotide?

Accepted Answer

A)   the phosphate group
B)   the sugar
C)   the base
D)   the sugar and the base

Question 9

Which of the following are pyrimidine nitrogenous bases?

Accepted Answer

A)   guanine and adenine
B)   cytosine and uracil
C)   thymine and guanine
D)   ribose and deoxyribose
E)   adenine and thymine

Question 10

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

Accepted Answer

A)   The two strands of the double helix would separate.
B)   The phosphodiester linkages of the polynucleotide backbone would be broken.
C)   The purines would be separated from the deoxyribose sugars.
D)   The pyrimidines would be separated from the deoxyribose sugars.
E)   All bases would be separated from the deoxyribose sugars.

Question 11

Which of the following statements about the 5' end of a polynucleotide strand of RNA is correct?

Accepted Answer

A)   The 5' end has a hydroxyl group attached to the number 5 carbon of ribose.
B)   The 5' end has a phosphate group attached to the number 5 carbon of ribose.
C)   The 5' end has phosphate attached to the number 5 carbon of the nitrogenous base.
D)   The 5' end has a carboxyl group attached to the number 5 carbon of ribose.
E)   The 5' end is the fifth position on one of the nitrogenous bases.

Question 12

What is the structural feature that allows DNA to replicate?

Accepted Answer

A)   sugar-phosphate backbone
B)   complementary pairing of the nitrogenous bases
C)   disulfide bonding (bridging)  of the two helixes
D)   twisting of the molecule to form an α-helix
E)   three-component structure of the nucleotides

Question 13

You have a polymer of DNA with 10 adenine bases followed by 10 cytosine bases. If that strand bonded to a strand of 20 thymine bases, how would the double helix shape vary from a typical DNA double helix?

Accepted Answer

A)   The double helix would be longer than normal.
B)   The double helix would be shorter than normal.
C)   One strand of the double helix would be longer than the other strand.
D)   The width of the double helix would vary along the length of the strand.

Question 14

The work of Bartel's group on the ribozyme RNA replicase supports which conclusion?

Accepted Answer

A)   An RNA world could produce molecules that could self-replicate.
B)   RNA molecules with variable characteristics could catalyze protein synthesis.
C)   Ribozymes had to be present in the first cells to generate copies of the genetic material
D)   Ribozymes were produced randomly through natural selection.

Question 15

Why do researchers think the first self-replicating molecule was RNA?

Accepted Answer

A)   RNA is the only type of molecule that can catalyze a chemical reaction.
B)   RNA can carry information and catalyze chemical reactions.
C)   Self-replicating molecules of RNA exist today, in human cells.
D)   Fossil evidence of such a molecule was recently discovered. B

Question 16

Which of the following includes all of the pyrimidines found in RNA and DNA?

Accepted Answer

A)   cytosine and uracil
B)   cytosine and thymine
C)   cytosine, uracil, and thymine
D)   cytosine, uracil, and guanine

Question 17

If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled?

Accepted Answer

A)   proteins
B)   cellulose
C)   amino acids
D)   nucleic acids
E)   glucose

Question 18

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence ________.

Accepted Answer

A)   5'TAACGT3'
B)   5'TGCAAT3'
C)   5'UAACGU3'
D)   3'UAACGU5'
E)   5'UGCAAU3'

Question 19

Both DNA and RNA ________.

Accepted Answer

A)   are information-containing molecules
B)   show primary, secondary, tertiary, and quaternary structure
C)   are highly reactive catalysts in cells
D)   naturally occur as a double helix

Question 20

In the context of chemical evolution, DNA's structure is interesting because it suggests a possible copying mechanism. What about DNA's structure facilitates copying?

Accepted Answer

A)   It has the same number of purines and pyrimidines.
B)   The nitrogenous bases are located on the inside of the double helix.
C)   The strands of the double helix are complementary.
D)   DNA always goes from 5 prime to 3 prime.

Exam 4: Nucleic Acids and the Rna World

One of the primary functions of RNA molecules is to ________.

Correct AnswerverifiedB

In the acid-base reaction described in the preceding paragraph about Nakano's research on RNAs, a proton (H+) is being transferred. What is acting as the proton acceptor?

Correct AnswerverifiedShow Answer

Which of the following best describes DNA's secondary structure?

Correct AnswerverifiedShow Answer

Which of the following did Watson and Crick already know when they were trying to determine the structure of DNA? The number of ________.

Correct AnswerverifiedShow Answer

Why is it that RNA can catalyze reactions but DNA cannot?

Correct AnswerverifiedA

What is the difference between a ribonucleotide and a deoxyribonucleotide?

Correct AnswerverifiedShow Answer

What feature of single nucleotides provides the energy needed for polymerization when nucleic acids are formed?

Correct AnswerverifiedShow Answer

What is/are the variable structure(s) of a nucleotide?

Correct AnswerverifiedShow Answer

Which of the following are pyrimidine nitrogenous bases?

Correct AnswerverifiedShow Answer

Enzymes that break down DNA catalyze the hydrolysis of the covalent bonds that join nucleotides together. What would happen to DNA molecules treated with these enzymes?

Correct AnswerverifiedShow Answer

Which of the following statements about the 5' end of a polynucleotide strand of RNA is correct?

Correct AnswerverifiedShow Answer

What is the structural feature that allows DNA to replicate?

Correct AnswerverifiedShow Answer

You have a polymer of DNA with 10 adenine bases followed by 10 cytosine bases. If that strand bonded to a strand of 20 thymine bases, how would the double helix shape vary from a typical DNA double helix?

Correct AnswerverifiedShow Answer

The work of Bartel's group on the ribozyme RNA replicase supports which conclusion?

Correct AnswerverifiedShow Answer

Why do researchers think the first self-replicating molecule was RNA?

Correct AnswerverifiedB

Which of the following includes all of the pyrimidines found in RNA and DNA?

Correct AnswerverifiedShow Answer

If cells are grown in a medium containing radioactive 32P-labeled phosphate, which of these molecules will be labeled?

Correct AnswerverifiedShow Answer

If one strand of a DNA molecule has the sequence of bases 5'ATTGCA3', the other complementary strand would have the sequence ________.

Correct AnswerverifiedShow Answer

Both DNA and RNA ________.

Correct AnswerverifiedShow Answer

In the context of chemical evolution, DNA's structure is interesting because it suggests a possible copying mechanism. What about DNA's structure facilitates copying?

Correct AnswerverifiedShow Answer

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