5. Transport Across The Cell Membrane Pt2

Question 1

Define Active Transport

Answer 1

Movement of substances across the membrane against the concentration gradient. Molecules move from low to high via carrier proteins and require ATP as an energy source.
Carriers:
Ions e.g. sodium and potassium
Bind -> shape change -> release

Question 2

Define Vesicular Transport

Answer 2

Transport across the membrane in vesicles – this is a form of mass transport. Form of active transport because energy is required to move vesicles into or out of a cell.
Two forms:
1. Endocytosis
2. Exocytosis

Question 3

Define Endocytosis

Answer 3

Endocytosis – taking vesicles containing liquids or solids into a cell

Question 4

Define Exocytosis

Answer 4

Exocytosis - when the contents of a vesicle are passed out of a cell

Question 5

Define Phagocytosis

Answer 5

• Means ‘cell eating’
• Solid particles are taken into the cell (endocytosis) by the cell membrane folding around the solid particle, forming a vacuole.
• The vacuole pinches off from the membrane and is suspended in the cell’s cytoplasm.

Question 6

Define Pinocytosis

Answer 6

• Means ‘cell drinking’
• Liquid particles are taken into the cell (endocytosis) by the cell membrane folding around the solid particle, forming a vacuole.
• The vacuole pinches off from the membrane and is suspended in the cell’s cytoplasm