3C Active Transport

Question 1

What?/Requires? - Protein Mediated Active Transport (e.g. of molecules it transports)

Answer 1

Involves moving molecules against their concentration gradient using protein pumps (e.g. ions like potassium)

• Protein pumps
• Energy in the form of ATP

Question 2

Protein-mediated active transport (‘Active Transport’) - Purpose/reason for occurrence

Answer 2

Purpose:

• Molecule cannot use simple diffusion = Charged molecule (e.g. Potassium)
• Molecule cannot use facilitated diffusion = moves against their concentration gradient
• Ensuring cells can access appropriate concentrations of particular molecules
• Control water movement
• Metabolic activities

Question 3

Identify + outline the three steps involved in protein mediated-transport (‘Active Transport’)

Answer 3

1. Binding (target molecule that is being transported will bind to a specific protein pump)
2. Conformational change (energy released from a reaction = conformational change in protein pump)
3. Release (target molecule released to the other side of the membrane once it has been pushed through the protein)

Question 4

Bulk Transport (define) (e.g. of molecules it transports)

Answer 4

A type of active transport that moves large molecules or groups of
molecules into or out of the cell using vesicles (e.g. pathogens + amino acids) that comes in two forms, ENDOCYTOSIS + ECOCYTOSIS

Question 5

Endocytosis (define + purpose/reason)

Answer 5

Define: When the contents of the vesicle are released from the cell

Purpose:
1. Cells can release their products
2. To transport molecules that are too large to use a protein channel

Question 6

Identify + outline the three steps involved in Endocytosis

Answer 6

1. Vesicular Transport

• When the vesicle that contains secretory products is transported to the plasma membrane

2. Fusion

• When the membrane of the vesicle and cell fuse

3. Release

• When the secretory products are released from the vesicle and out of the cell

Question 7

Endocytosis (define + purpose/reason)

Answer 7

Define: Involves transporting large molecules/groups of molecules into the cell using vesicles

Purpose:

• Transport molecules that cells require to survive but are too large to take in through protein channels in the plasma membrane
• To use the molecules for metabolic processes/structural elements of the cell
• To act as a defensive mechanism

Question 8

Identify + outline the three steps involved in Endocytosis

Answer 8

1. Fold (When the plasma membrane folds inwards until it creates a cavity that can fill itself with extracellular fluid + target molecules)
2. Trap (When the plasma membrane folds back on itself until the two ends of the membrane meet + fuse in order to trap the target molecules inside a vesicle)
3. Bud (When vesicles bud off from the plasma membrane to then be transported for either appropriate cellular function/to fuse with a lysosome for digestion)