Q: Which of the following is the correct chemical reaction for the formation of a phosphodiester bond between two nucleotides?

$$\mathrm{Nucleotide}_1 + \mathrm{Nucleotide}_2 \rightarrow \mathrm{Nucleotide}_1{-}3'\text{-}5'\text{ phosphodiester bond}-\mathrm{Nucleotide}_2 + \mathrm{H}_2\mathrm{O}$$

Question 1

Which of the following best describes the primary structure of a nucleic acid?

Accepted Answer

The unique sequence of nucleotide bases in the nucleic acid polymer.

Question 2

What type of bond connects the 3'-hydroxyl group of one nucleotide to the 5'-phosphate group of the next nucleotide in a nucleic acid?

Accepted Answer

Phosphodiester bond

Question 3

Given the RNA sequence A-C-G-U, which base is located at the free 3'-hydroxyl end?

Accepted Answer

Uracil

Question 4

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

Accepted Answer

Carboxyl group

Question 5

A nucleoside differs from a nucleotide in that it lacks which component?

Accepted Answer

Phosphate group

Question 6

If a nucleic acid sequence is written as 5'-A-G-C-U-3', which base is at the free 5'-phosphate end?

Accepted Answer

Adenine

Question 7

Which statement best explains why the sequence of bases in nucleic acids is important?

Accepted Answer

It carries genetic information from one cell to the next.

Question 8

Which of the following correctly describes the direction in which a nucleic acid sequence is read?

Accepted Answer

From the free 5'-phosphate end to the free 3'-hydroxyl end.

Question 9

Which of the following is a correct representation of a phosphodiester bond in nucleic acids?

Accepted Answer

$$\mathrm{Sugar}-\mathrm{Phosphate}-\mathrm{Sugar}$$

Question 10

A scientist isolates a molecule with a free 5'-phosphate group and a free 3'-hydroxyl group. What type of molecule is this most likely to be?

Accepted Answer

A nucleic acid

Question 11

Which of the following best describes the difference between DNA and RNA based on the bases present?

Accepted Answer

RNA contains uracil instead of thymine.

Question 12

If a mutation changes the sequence of bases in a nucleic acid, which level of structure is directly affected?

Accepted Answer

Primary structure

Question 13

Which of the following is the correct chemical reaction for the formation of a phosphodiester bond between two nucleotides?

Accepted Answer

$$\mathrm{Nucleotide}_1 + \mathrm{Nucleotide}_2 ightarrow \mathrm{Nucleotide}_1{-}3'	ext{-}5'	ext{ phosphodiester bond}-\mathrm{Nucleotide}_2 + \mathrm{H}_2\mathrm{O}$$

Question 14

A patient’s genetic disorder is traced to a single base change in their DNA. Which property of nucleic acids does this most directly affect?

Accepted Answer

The primary structure of the nucleic acid

Question 15

Which of the following is true regarding the ends of a nucleic acid polymer?

Accepted Answer

One end has a free 5'-phosphate group and the other has a free 3'-hydroxyl group.

Question 16

Which of the following would be the correct abbreviated sequence for an RNA strand with the bases adenine, cytosine, guanine, and uracil from 5' to 3'?

Accepted Answer

A-C-G-U

Question 17

In a nucleic acid, the phosphodiester bond forms between which two atoms?

Accepted Answer

The 3'-oxygen atom of one sugar and the 5'-phosphorus atom of the next sugar

Question 18

Which of the following best explains why nucleic acids are considered polymers?

Accepted Answer

They are made up of repeating units of nucleotides.

Question 19

A researcher is analyzing a nucleic acid and finds that the sequence is read from the top base to the bottom base. What does this indicate about the orientation?

Accepted Answer

It is read from the 5'-phosphate end to the 3'-hydroxyl end.

Nucleic Acids: Structure and Sequence (Chapter 17 Study Notes)

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