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CAIE A-Level Biology 4.1.2 Arrangement of Membrane Components

Practise positioning cholesterol among phospholipids and distinguishing glycolipids from glycoproteins by their lipid or protein attachment and external carbohydrate chains.

Syllabus
2028–2030
Course
Biology 9700
Level
AS

Exam points

  • place cholesterol’s hydroxyl group by polar heads and its non-polar region among tails
  • show carbohydrate chains of glycolipids and glycoproteins on the extracellular surface
  • distinguish lipid-linked from protein-linked carbohydrate components in membrane diagrams

4.1.2—Membrane component arrangement question 1

[Maximum number: 1]

Fig. 1.1 is a diagram representing part of the phospholipid bilayer of a cell surface membrane.

Fig. 1.1

Fig. 1.1

Cholesterol is an important lipid component of many cell surface membranes. Fig. 1.2 shows the structure of a cholesterol molecule.

Fig. 1.2

Fig. 1.2

Using the information in Fig. 1.2, explain the orientation (positioning) of cholesterol molecules in the phospholipid bilayer, as shown in Fig. 1.1.

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