$$ \text{Nucleotide}_1 + \text{Nucleotide}_2 \rightarrow \text{Dinucleotide} + H_2O $$

Question 1

Which of the following statements best describes the RNA world hypothesis?

Accepted Answer

RNA was the first molecule to store genetic information and catalyze its own replication.

Question 2

A nucleotide is composed of which three components?

Accepted Answer

Phosphate group, five-carbon sugar, nitrogenous base

Question 3

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

Accepted Answer

Uracil

Question 4

What type of chemical reaction is responsible for the polymerization of nucleotides into nucleic acids?

Accepted Answer

Condensation reaction

Question 5

Which bond forms between the phosphate group on the 5' carbon of one nucleotide and the —OH group on the 3' carbon of another?

Accepted Answer

Phosphodiester linkage

Question 6

If a DNA strand has the sequence 5'-ATTAGC-3', what is the complementary strand sequence?

Accepted Answer

3'-TAATCG-5'

Question 7

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

Accepted Answer

It is held together by phosphodiester linkages, hydrogen bonds, and hydrophobic interactions.

Question 8

What is the main difference between the sugars in DNA and RNA?

Accepted Answer

DNA contains deoxyribose, which lacks an oxygen atom at the 2' carbon.

Question 9

Which of the following is a purine?

Accepted Answer

Adenine

Question 10

What is the significance of complementary base pairing in DNA replication?

Accepted Answer

It ensures that each strand is copied exactly, producing two identical daughter molecules.

Question 11

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

Accepted Answer

RNA strands fold over to form hairpin structures due to complementary base pairing within the same strand.

Question 12

Which molecule is an example of an activated nucleotide that drives polymerization reactions?

Accepted Answer

Adenosine triphosphate (ATP)

Question 13

What is the role of histones in DNA tertiary structure?

Accepted Answer

They are DNA-binding proteins that DNA wraps around to form compact structures.

Question 14

Which of the following is NOT a function of RNA?

Accepted Answer

Storing genetic information for long-term inheritance

Question 15

Which of the following equations correctly represents the condensation reaction that forms a phosphodiester bond between two nucleotides?

Accepted Answer

$$ 	ext{Nucleotide}_1 + 	ext{Nucleotide}_2 ightarrow 	ext{Dinucleotide} + H_2O $$

Question 16

Which feature of DNA allows it to serve as a reliable information-storage molecule?

Accepted Answer

Its stability due to phosphodiester linkages, hydrogen bonds, and hydrophobic interactions

Question 17

Which of the following statements about ribozymes is true?

Accepted Answer

Ribozymes are RNA molecules that catalyze chemical reactions.

Question 18

Which of the following best describes the directionality of nucleic acid strands?

Accepted Answer

They have a 5' phosphate group at one end and a 3' hydroxyl group at the other end.

Question 19

Which of the following is a real-world application of the concept of complementary base pairing?

Accepted Answer

Designing primers for PCR amplification in genetic testing

Question 20

Which of the following statements about the tertiary structure of RNA is correct?

Accepted Answer

RNA tertiary structure forms when secondary structures fold into more complex shapes.

Nucleic Acids and an RNA World (Chapter 4 Study Notes)

Study Guide - Practice Questions