$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} \rightarrow \mathrm{ADP} + \mathrm{P}_i + \text{energy}$$

Question 1

Which of the following best describes the difference between a nucleoside and a nucleotide?

Accepted Answer

A nucleoside contains a nitrogenous base and a sugar, while a nucleotide contains a nitrogenous base, a sugar, and a phosphate group.

Question 2

Which of the following equations correctly represents the formation of a phosphodiester bond during DNA synthesis?

Accepted Answer

$$\mathrm{Nucleotide}_1 + \mathrm{Nucleotide}_2 \rightarrow \mathrm{Dinucleotide} + \mathrm{H}_2\mathrm{O}$$

Question 3

Which of the following is NOT a function of nucleotides in the cell?

Accepted Answer

Acting as enzymes for protein synthesis

Question 4

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

Accepted Answer

The two strands of DNA are antiparallel and held together by hydrogen bonds between complementary bases.

Question 5

Which of the following best explains why ATP is considered the universal energy currency in biological systems?

Accepted Answer

ATP contains high-energy phosphoanhydride bonds that release energy upon hydrolysis.

Question 6

Which of the following base pairs is stabilized by three hydrogen bonds in the DNA double helix?

Accepted Answer

Guanine–Cytosine

Question 7

A mutation causes the replacement of cytosine with uracil in a DNA strand. Which chemical reaction most likely occurred?

Accepted Answer

Deamination

Question 8

Which of the following is a pyrimidine base found in RNA but not in DNA?

Accepted Answer

Uracil

Question 9

Which of the following best describes the role of histones in the organization of DNA in eukaryotic cells?

Accepted Answer

Histones are positively charged proteins that facilitate the packaging of DNA into nucleosomes.

Question 10

Which of the following statements about the major and minor grooves of DNA is correct?

Accepted Answer

The major groove is wider and more accessible for protein binding than the minor groove.

Question 11

Which of the following equations correctly represents the hydrolysis of ATP to ADP and inorganic phosphate?

Accepted Answer

$$\mathrm{ATP} + \mathrm{H}_2\mathrm{O} ightarrow \mathrm{ADP} + \mathrm{P}_i + 	ext{energy}$$

Question 12

Which of the following is a function of cAMP in the cell?

Accepted Answer

Serves as an intracellular second messenger in signal transduction pathways

Question 13

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

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 14

Which of the following is a correct statement about tRNA?

Accepted Answer

tRNA brings amino acids to the ribosome during protein synthesis.

Question 15

Which of the following is a real-life application of nucleoside analogues?

Accepted Answer

They are used as antiviral drugs to inhibit HIV replication.

Question 16

Which of the following best explains why RNA is generally less stable than DNA?

Accepted Answer

RNA contains a 2' hydroxyl group on the ribose sugar, making it more susceptible to hydrolysis.

Question 17

Which of the following statements about the human genome is correct?

Accepted Answer

The human genome is organized into chromosomes and contains both coding and non-coding regions.

Question 18

Which of the following best describes the function of rRNA in the ribosome?

Accepted Answer

rRNA provides the catalytic activity for peptide bond formation and helps decode mRNA.

Question 19

Which of the following is a correct description of the directionality of a DNA strand?

Accepted Answer

DNA strands run from the 5' end to the 3' end.

Nucleic Acids: Structure, Chemistry, and Biological Roles

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