Cell Membrane Transport

Question 1

State the definition of Diffusion

Answer 1

The net movement of particles down a concentration gradient from a region of high concentration to a region of low concentration. It is a passive process.

Question 2

What factors affect the rate of diffusion?

Answer 2

• Concentration Gradient
• Increasing Surface Area
• Distance/Thickness
• Stirring/Moving
• Temperature
• Size of molecule

Question 3

What are the 2 types and 3 essential Characteristics of Facilitated Diffusion?

Answer 3

1. Carrier Mediated Facilitated Diffusion
2. Channel Mediated Facilitated Diffusion

3 characteristics are:
i. Specific
ii. Passive
iii. Saturates

Question 4

State the definition of Osmosis

Answer 4

The diffusion of water. The net movement of water molecules from a region of high water concentration to a region of low water concentration, through a partially-permeable membrane.

Question 5

What is Water Potential?

Answer 5

The tendency of water molecules in a system to move.

Pure water has the highest water potential. Solutions have a lower water potential than pure water and have a negative water potential.

Question 6

State the definition of Active Transport

Answer 6

The movement of molecules or ions across a cell membrane against their concentration gradient (From low concentration to high concentration). This process requires ATP (Energy).

Question 7

What is Endocytosis?

Answer 7

Bulk Transport of material into cell and can be split into three processes:

1. Phagocytosis - process by which certain living cells ingest or engulf other cells or particles
2. Pinocytosis - ingestion of liquid into new cell by budding of small vesicles from cell membrane.
3. Receptor-mediated endocytosis - triggered by specific receptor