DP Biology (first assessment 2025)

Question 22M.1A.SL.TZ1.6

Date	May 2022	Marks available	[Maximum mark: 1]	Reference code	22M.1A.SL.TZ1.6
Level	SL	Paper	1A	Time zone	TZ1
Command term		Question number	6	Adapted from	N/A

[Maximum mark: 1]

22M.1A.SL.TZ1.6

What are linked by hydrogen bonds?

A. Hydrogen and oxygen within a water molecule

B. Phosphate and sugar within a DNA molecule

C. Base and sugar between DNA nucleotides

D. Hydrogen and oxygen in different water molecules

[1]

Markscheme

Examiners report

Only 40 % of candidates answered this question correctly. A common misunderstanding was to think that hydrogen bonds are within water molecules (intramolecular) rather than between water molecules (intermolecular).

Syllabus sections

A. Unity and diversity » A1.2. Nucleic acids » A1.2.6. DNA as a double helix made of two antiparallel strands of nucleotides with two strands linked by hydrogen bonding between complementary base pairs

A. Unity and diversity » A1.1. Water » A1.1.2. Hydrogen bonds as a consequence of the polar covalent bonds within water molecules

Question 22M.1A.SL.TZ1.6

Select a Test

Syllabus sections

Confirm action