Question 1

Which of the following statements correctly distinguishes between a nucleotide and a nucleoside?

Accepted Answer

A nucleotide consists of a nitrogenous base, a pentose sugar, and a phosphate group, while a nucleoside lacks the phosphate group.

Question 2

Which of the following base pairs is held together by three hydrogen bonds in DNA?

Accepted Answer

Cytosine and Guanine

Question 3

A double-stranded DNA fragment is 120 base pairs long and has twice as many Thymines as Guanines. How many hydrogen bonds hold the two strands together?

Accepted Answer

$280$

Question 4

Which of the following nucleotides is found only in RNA and not in DNA?

Accepted Answer

UTP

Question 5

If a DNA fragment contains 80 thymidylic acid and 110 deoxyguanylic acid residues, how many phosphorus atoms does it contain?

Accepted Answer

$380$

Question 6

A double-stranded DNA fragment has 1,800 nitrogen atoms and four times as many Adenines as Cytosines. How many hydrogen bonds hold the two strands together?

Accepted Answer

$1,320$

Question 7

Which of the following best describes the flow of genetic information according to the central dogma of molecular biology?

Accepted Answer

DNA $\rightarrow$ RNA $\rightarrow$ Protein

Question 8

A DNA fragment is held together by 385 hydrogen bonds and has twice as many Thymines as Guanines. How many base pairs does this fragment contain?

Accepted Answer

$165$

Question 9

Which of the following is a purine base found in both DNA and RNA?

Accepted Answer

Adenine

Question 10

A double-stranded DNA fragment has 78 3'-5' phosphodiester linkages and 295 nitrogen atoms. How many hydrogen bonds are present between the two strands?

Accepted Answer

$95$

Question 11

If a DNA molecule has 23% Adenine, what is the percentage of Guanine?

Accepted Answer

$27\%$

Question 12

Which of the following best explains why ATP is considered the 'energy currency' of the cell?

Accepted Answer

It contains three phosphate groups that can be hydrolyzed to release energy.

Question 13

A double-stranded, circular chromosome of Hemophilus influenzae contains 3,660,000 phosphorus atoms. Adenine and Thymine constitute 46% of the nitrogenous bases. How many hydrogen bonds are present between all the nitrogenous bases?

Accepted Answer

$4,648,200$

Question 14

Which of the following is true regarding the structure of DNA?

Accepted Answer

Adenine pairs with Thymine via two hydrogen bonds.

Question 15

A DNA fragment has 555 base pairs and four times as many Adenines as Guanines. How many 3'-5' phosphodiester linkages does it have?

Accepted Answer

$1,108$

Question 16

Which of the following nucleotides does NOT exist in nature?

Accepted Answer

dUTP

Question 17

A DNA fragment contains 775 nitrogen atoms and three times as many Cytosines as Adenines. How many hydrogen bonds hold the two strands together?

Accepted Answer

$1,125$

Question 18

Which of the following best describes the difference between DNA and RNA?

Accepted Answer

DNA is double-stranded and contains thymine, while RNA is single-stranded and contains uracil.

Question 19

The E. coli chromosome is $4.65 	imes 10^6$ base pairs long. If it is completely labeled with $^{15}N$ (radioactive nitrogen), how many additional neutrons does it have compared to a nonradioactive chromosome?

Accepted Answer

$34,921,500$

Question 20

Which of the following is a correct pairing of a nucleoside and its corresponding nucleotide in RNA?

Accepted Answer

Uridine and UTP

Nucleic Acids: Structure, Function, and Quantitative Analysis

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