Topic 2 Cells: Membrane Properties and Components

Question 1

• Allows small, uncharged, non-polar, hydrophobic molecules to freely pass the membrane
• Polar molecules may cross if they are small and uncharged
• Every other substance requires a transporter

Answer 1

Phospholipid Membrane Permeability

Question 2

• Adds rigidity to animal cell membranes
• Maintains fluidity of the membrane at low temps
• Sterols provide analogous function in plant cells
• Prokaryotes do not have cholesterol, they use hopanoids instead

Answer 2

Cholesterol

Question 3

• A carbohydrate coat that covers the outer face of the cell wall of some bacteria and the outer face of the membrane in some animal cells
• Consists of glycolipids attached to the plasma membrane, and glycoproteins that serve as recognition proteins
• Functions: adhesive capabilities, barrier to infection, markers for cell-cell recognition

Answer 3

Glycocalyx