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Homework 4.1
Cell membranes and transport
This worksheet relates the structure of the cell surface membrane to its role in cell signalling. Making
your own diagram is an excellent way of checking your knowledge of a structure. Part d asks you to
apply your knowledge to a new situation.
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a
Make a drawing to show the structure of the cell surface membrane.
Label the following components:
•
a phospholipid molecule
•
a cholesterol molecule
•
a glycolipid
•
a channel protein
•
a glycoprotein.
[5]
b Describe the properties of a phospholipid molecule.
[2]
c
[2]
Give two functions of glycoproteins in the cell surface membrane.
d Living cells are able to detect changes in their environment and to make appropriate responses.
For example, hormones interact with receptors on their target cells, bringing about specific
changes in the target cells. This is an example of cell signalling.
The hormone secretin attaches to the cell surface membrane of cells in the pancreas and
stimulates these cells to secrete water and hydrogencarbonate ions.
i
e
Explain why secretin is described as a hormone.
[2]
ii Explain why secretin attaches specifically to the membrane of cells in the pancreas.
[2]
The hormone adrenaline has an important role in the control of blood glucose. Make a flow
diagram to show how adrenaline interacts with a target cell, resulting in the activation of
enzymes.
[3]
[Total: 16]
Cambridge International AS and A Level Biology © Cambridge University Press 2014
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