1.3 Cells: Membrane Structure & Transport

To provide hydrophilic channels.

To regulate membrane fluidity.

To assist active transport.

To assist cell adhesion.

A phospholipid bilayer with a series of proteins that are free to move around within the membrane.

A phospholipid bilayer.

A phospholipid bilayer with a layer of protein on either side.

A phospholipid bilayer with a series of proteins in fixed positions throughout.

The higher the proportion of unsaturated fatty acid tails in a membrane, the higher the membrane fluidity.

Cholesterol can restrict the motion of the molecules in a membrane, increasing membrane fluidity.

Cells do not need to regulate membrane fluidity.

The lower the proportion of unsaturated fatty acid tails in a membrane, the higher the membrane fluidity.

Water moving through a partially permeable membrane.

Phagocytosis of a pathogen.

Exocytosis.

Endocytosis.