Practise CAIE AS Biology 4.1 by explaining membrane structure and component roles, then tracing how ligand binding at cell-surface receptors triggers a response.
What causes the phosphate heads of phospholipids to become polar?
The phosphate heads are joined to water molecules by hydrogen bonds.
The phosphate heads are insoluble in water.
The phosphate heads become ionised in water.
The phosphate heads are joined to water molecules by covalent bonds.
C
Where in the cell surface membrane are the carbohydrate chains of glycoproteins and glycolipids mainly located?
glycoproteins
glycolipids
inner surface
inner surface
inner surface
outer surface
outer surface
inner surface
outer surface
outer surface
D
Which component of cell surface membranes helps to reduce fluidity of the phospholipids at high temperatures?
phosphate groups
unsaturated fatty acids
cholesterol
proteins
C
Which statement about cell signalling is correct?
One type of receptor molecule will recognise all ligands in the body.
The binding of a ligand may cause a change to the shape of the receptor.
The receptors for ligands are always found on the inside of cells.
The same ligand is made by all of the cells in the body.
B