Cell Membrane Transport

Question 1

Describe phagocytosis (a type of endocytosis).

Answer 1

• Cells engulf large particles (phagocytes), bringing bacteria from external environment into internal
• Invagination of plasmalemma produces vacuole
• Vacuole enables transfer of substances from external environment into the cell

Question 2

Describe Pinocytosis (type of endocytosis)

Answer 2

• Vesicles bring in small amounts of particle into cell by invagination

Question 3

Explain what passive transport is

Answer 3

• Solution diffuses down the concentration gradient

Question 4

What is Osmosis?

Answer 4

• Diffusion of free water across selectively permeable membrane

Question 5

Difference between osmosis and diffusion?

Answer 5

• Only solvent molecules (osmosis)
• Both solute and solvent (diffusion)
• Semi-permeable membrane needed (osmosis)
• No need (diffusion)

Question 6

how do hydrophilic molecules move across the membrane?

Answer 6

• Channel proteins: provide corridors in which they diffuse very quickly from 1 side of membrane to another
• Aquaporins aid massive levels of osmosis
• Ion channels: Channel proteins that transport ions (gated channels, open and close in response to a stimuli)
• Carrier proteins: undergo change in shpae to translocate solute-binding site across membrane

Question 7

Describe the process of exocytosis.

Answer 7

• Vesicles within cell carry molecules to plasma membrane

* Once vessicles at plasmalemma, it connects with plasmalemma, causing release of molecules to outside