Question 1

Which of the following best explains why DNA is a more stable information-storage molecule than RNA?

Accepted Answer

DNA has a deoxyribose sugar lacking a 2' hydroxyl group, making it less reactive and more resistant to hydrolysis.

Question 2

A scientist is studying a molecule that can both store genetic information and catalyze its own replication. According to the RNA world hypothesis, which molecule is she most likely studying?

Accepted Answer

A ribozyme (RNA)

Question 3

Which of the following correctly describes the directionality of a nucleic acid strand?

Accepted Answer

It runs from the 5' phosphate group to the 3' hydroxyl group.

Question 4

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

Accepted Answer

Adenine

Question 5

During DNA replication, which type of bond is broken to separate the two strands?

Accepted Answer

Hydrogen bonds

Question 6

Which of the following best describes the process by which nucleotides are joined to form nucleic acids?

Accepted Answer

Condensation reactions forming phosphodiester linkages

Question 7

A mutation changes a cytosine (C) to a thymine (T) in a DNA molecule. Which of the following base-pairing changes would you expect as a result?

Accepted Answer

The mutated T will pair with A instead of G.

Question 8

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

Accepted Answer

It consists of two antiparallel strands held together by hydrogen bonds between complementary bases.

Question 9

Which of the following best explains why RNA is more versatile than DNA?

Accepted Answer

RNA can fold into complex three-dimensional shapes, allowing it to catalyze reactions and store information.

Question 10

Which of the following is a function of nucleotides other than serving as building blocks for nucleic acids?

Accepted Answer

They serve as energy carriers, such as ATP.

Question 11

A researcher is attempting to synthesize nucleotides under prebiotic conditions. Which of the following is most likely to facilitate the concentration and formation of ribose, a key sugar in nucleotides?

Accepted Answer

Binding to reactive minerals in deep-sea hydrothermal vents

Question 12

Which of the following best describes the role of activated nucleotides in nucleic acid polymerization?

Accepted Answer

They have extra phosphate groups, increasing potential energy and making polymerization spontaneous.

Question 13

Which of the following is true regarding complementary base pairing in nucleic acids?

Accepted Answer

In DNA, adenine pairs with thymine and cytosine pairs with guanine.

Question 14

Which of the following best describes the tertiary structure of DNA in eukaryotic cells?

Accepted Answer

DNA forms supercoils and wraps around histone proteins to become highly compacted.

Question 15

Which of the following is a key difference between the primary structure of DNA and RNA?

Accepted Answer

DNA contains deoxyribose, while RNA contains ribose.

Question 16

A ribozyme is discovered that can catalyze the formation of phosphodiester bonds. Why is this discovery significant for the RNA world hypothesis?

Accepted Answer

It supports the idea that RNA could have both stored genetic information and catalyzed its own replication.

Question 17

Which of the following best explains why the sequence of bases in DNA is compared to the order of letters in a word?

Accepted Answer

Because the sequence encodes information, and the order of bases determines genetic meaning.

Question 18

Which of the following is NOT a characteristic of the double helix structure of DNA?

Accepted Answer

It is held together by peptide bonds between bases.

Question 19

A laboratory experiment isolates a ribozyme that can add 14 nucleotides to an existing RNA strand. What does this experiment demonstrate about RNA?

Accepted Answer

RNA can act as a catalyst and facilitate its own replication, supporting the RNA world hypothesis.

Nucleic Acids and the RNA World: Structure, Function, and Evolution

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