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

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

Question 1

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

Accepted Answer

RNA can both store genetic information and catalyze chemical reactions due to its ability to fold into complex three-dimensional shapes.

Question 2

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

Accepted Answer

Adenine

Question 3

What type of bond forms between the phosphate group of one nucleotide and the hydroxyl group on the sugar of another nucleotide during nucleic acid polymerization?

Accepted Answer

Phosphodiester bond

Question 4

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

Accepted Answer

It has an unlinked 5' phosphate group at one end and an unlinked 3' hydroxyl group at the other.

Question 5

Which of the following is a key feature of the Watson-Crick model of DNA structure?

Accepted Answer

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

Question 6

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

Accepted Answer

DNA lacks the 2' hydroxyl group present in RNA, making it less susceptible to hydrolysis.

Question 7

Which of the following is true regarding the secondary structure of RNA?

Accepted Answer

RNA forms hairpin structures due to complementary base pairing within the same strand.

Question 8

Which of the following best describes the role of ribozymes in the RNA world hypothesis?

Accepted Answer

Ribozymes catalyzed reactions necessary for their own replication and possibly for the synthesis of ribonucleotides.

Question 9

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 10

A scientist isolates a nucleic acid with the following characteristics: it contains uracil, is single-stranded, and can catalyze the formation of phosphodiester bonds. What is this molecule most likely to be?

Accepted Answer

RNA

Question 11

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

Accepted Answer

Proteins are more versatile and efficient catalysts than ribozymes, allowing for more complex biochemical reactions.

Question 12

Which of the following is NOT a requirement for the first self-replicating molecule according to the chemical evolution theory?

Accepted Answer

Ability to be enclosed in a lipid membrane

Question 13

Which of the following best describes the process of DNA replication?

Accepted Answer

DNA strands are separated, and free deoxyribonucleotides form hydrogen bonds with complementary bases on the template strand, followed by formation of phosphodiester linkages.

Question 14

Which of the following is a correct pairing of a nitrogenous base with the type of nucleic acid in which it is found?

Accepted Answer

Uracil – RNA

Question 15

Which of the following best explains why activated nucleotides are necessary for nucleic acid polymerization in cells?

Accepted Answer

Activated nucleotides contain extra energy in the form of additional phosphate groups, making the polymerization reaction spontaneous.

Question 16

Which of the following is a real-world example supporting the RNA world hypothesis?

Accepted Answer

Modern ribozymes are essential for protein production, and without them, proteins could not be made.

Bio 190 Chapter 4: Nucleic Acids and an RNA World: Structure, Function, and Evolution

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