Question 1

Which of the following best describes the RNA world hypothesis?

Accepted Answer

RNA both stored genetic information and catalyzed its own replication before DNA and proteins evolved.

Question 2

Which of the following is NOT a component of a nucleotide?

Accepted Answer

A carboxyl group

Question 3

Which nitrogenous base is found only in RNA and not in DNA?

Accepted Answer

Uracil

Question 4

What type of chemical reaction links nucleotides together to form nucleic acids?

Accepted Answer

Condensation

Question 5

Which of the following statements about the directionality of nucleic acids is correct?

Accepted Answer

The 5' end has an unlinked phosphate group and the 3' end has an unlinked hydroxyl group.

Question 6

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

Accepted Answer

DNA contains deoxyribose, which lacks a hydroxyl group at the 2' carbon, making it less reactive.

Question 7

Which of the following is a correct complementary base pair in DNA?

Accepted Answer

Adenine–Thymine

Question 8

What is the main function of DNA in cells?

Accepted Answer

Storing genetic information required for growth and reproduction

Question 9

Which of the following best describes the tertiary structure of DNA?

Accepted Answer

DNA forms supercoils and wraps around histone proteins for compaction.

Question 10

Which of the following is true about the process of DNA replication?

Accepted Answer

Hydrogen bonds between bases are broken, and each strand serves as a template for a new complementary strand.

Question 11

Which of the following is a function unique to RNA compared to DNA?

Accepted Answer

Catalyzing chemical reactions as ribozymes

Question 12

Which of the following best explains why ATP is considered an 'activated nucleotide'?

Accepted Answer

ATP contains three phosphate groups, which increases its potential energy.

Question 13

A scientist isolates a nucleic acid that contains the bases adenine, guanine, cytosine, and uracil. Which type of molecule is this?

Accepted Answer

RNA

Question 14

Which of the following is a property of the DNA double helix that contributes to its stability?

Accepted Answer

All of the above

Question 15

Which of the following experimental findings provided evidence for the helical structure of DNA?

Accepted Answer

X-ray crystallography measurements of atomic distances

Question 16

Which of the following best describes the secondary structure of RNA?

Accepted Answer

A single strand folding back on itself to form a hairpin loop

Question 17

Which of the following is a key reason why most researchers believe RNA was the first self-replicating molecule?

Accepted Answer

RNA can both store genetic information and catalyze its own replication.

Question 18

Which of the following is a real-world application of ribozymes?

Accepted Answer

Ribozymes catalyze the formation of peptide bonds during protein synthesis in ribosomes.

Question 19

Which of the following best explains why the evolution of protein enzymes marked the end of the RNA world?

Accepted Answer

Proteins are more efficient catalysts than RNA.

Question 20

A mutation causes a DNA molecule to have more purines than pyrimidines. What is the most likely consequence?

Accepted Answer

The DNA double helix will be destabilized due to improper base pairing.

Chapter 4: Nucleic Acids and the RNA World – Study Notes

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