3A Introduction to the plasma membrane

The inside of the cell is referred to as the​ (a)   and the outside of the cell is known as the ​ (b)   .

• intracellular environment
• extracellular environment

The plasma membrane is selectively permeable. What does this mean?

• All molecules can pass through the membrane

• Some molecules can pass through the membrane

• No molecules can pass through the membrane

Label the following diagram of a plasma membrane.

a

b

c

d

carbohydrate

protein channel

cholesterol

phospholipid

Classify the following as characteristics of the head or tail of a phospholipid.

Groups:

(a) Head

,

(b) Tail

• Polar

• Hydrophilic

• Fatty acids

• Hydrophobic

• Attracted to water

• Repelled by water

• Phosphate

• Non-polar

Which of the following shows the correct arrangement of a phospholipid bilayer?

• 
• 
• 

Match the following structures found in the plasma membrane with their functions.

• Cholesterol

• Transport, catalysis, communication and adhesion

• Carbohydrates

• Cell-cell communication, signalling and adhesion.

• Proteins

• Regulating the fluidity of the membrane

The plasma membrane can be described as ​ (a)   as the phosopholipids are always moving around, and as ​ (b)   as it has many carbohydrates and proteins embedded in it.

• fluid
• a mosaic
• non-permeable