DP Biology (last assessment 2024)

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Question 22N.2.HL.TZ0.a

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Date November 2022 Marks available [Maximum mark: 3] Reference code 22N.2.HL.TZ0.a
Level HL Paper 2 Time zone TZ0
Command term Draw Question number a Adapted from N/A
a.
[Maximum mark: 3]
22N.2.HL.TZ0.a

A wide variety of organic compounds are used by living organisms.

Draw a diagram to show the ring structure of D-ribose.

[3]

Markscheme
  1. ring with four carbons and one oxygen atom;
  2. CH2OH attached to C4;
  3. OH and H attached by single bonds to C1, C2 and C3 with OH facing downwards on C2 and C3;

Numbering of carbons not required for mpa.

Carbons in the ring can be shown as a junction of single bonds without the letter C, but oxygen must be shown as O.

For mpc OH can face up or down.

Examiners report

Well-prepared candidates were able to draw the structure of ribose with every atom correct. Most others got at least part of the molecule. Common faults were putting six atoms in the ring or drawing deoxyribose instead of ribose.

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