IB Diploma Programme (DP) - SL & HL · Biology

A1.2 Nucleic acids (Molecules): Practice Questions

5 multiple-choice questions marked as you go, and 5 written questions with worked solutions. All on A1.2 Nucleic acids (Molecules).

10 questions26 marksFree, no account

Question 1

1 mark

Which of the following components is not found in a DNA nucleotide?

Question 2

1 mark

The phosphodiester bond links the phosphate group of one nucleotide to which specific carbon atom of the pentose sugar of the next nucleotide?

Question 3

1 mark

While the canonical B-form DNA is right-handed, certain sequences, particularly those with alternating purine-pyrimidine repeats, can transiently adopt the Z-form. What key structural feature distinguishes Z-DNA from B-DNA?

Question 4

1 mark

Which base pairs with Adenine in a DNA molecule?

Question 5

1 mark

Why is RNA generally considered less stable and more reactive than DNA?

Question 6

2 marks

State the specific name of the sugar found in a DNA nucleotide and identify the chemical group located at the 5' carbon position of this sugar.

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Question 7

4 marks

Explain why the antiparallel orientation of the two strands is crucial for the proper formation and stability of the DNA double helix.

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Question 8

6 marks

The deamination of cytosine naturally produces uracil. Explain why the presence of thymine instead of uracil in DNA provides a significant evolutionary advantage in terms of genetic stability and repair.

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Question 9

4 marks

In a double-stranded DNA sample extracted from a specific organism, $18\%$ of the bases are Cytosine (C).

a) Calculate the percentage of Adenine (A) bases present in this DNA sample.

b) Explain the chemical basis for the observation that the amount of Guanine equals the amount of Cytosine, referencing the structure of the DNA double helix.

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Question 10

5 marks

Eukaryotic DNA is highly organized within the nucleus.

a) Describe the structure of a nucleosome, including the components involved.

b) Explain the role of nucleosomes and subsequent folding processes in the efficient packaging of the long linear DNA molecules within the confines of the eukaryotic nucleus.

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