Unit 1, AOS1, Chapter 3C: Active Transport

Define Active Transport

Movement of molecules across a semipermeable membrane against their concentration gradient (low to high) that requires energy, usually in the form of ATP

Identify the 2 types of Active Transport

1. Active Transport (protein-mediated)

2. Bulk Transport

List the 3 steps of Active Transport

1. Binding (molecule binds to a transport protein)

2. Conformational Change (energy release causes the protein pump to change shape)

3. Release

Provide 2 reasons a cell might require active transport of molecules

A cell might require higher concentrations of a molecule within the cell for metabolic activities or to manipulate water movement (osmosis) by changing the areas of low and high solute concentration

Define Bulk Transport

Bulk transport is a type of active transport that moves large molecules or groups of molecules - such as amino acids, proteins, signalling molecules, or pathogens - into or out of the cell using vesicle

Identify the 2 types of bulk transport

1. Endocytosis

2. Exocytosis

Identify the 3 steps of Exocytosis

1. Vesicular transport

2. Fusion

3. Release

Identify the 3 steps of Endocytosis

1. Fold

2. Trap

3. Bud

Suggest what may occur if a cell engulfs an invader or toxin

A lysosome may fuse with the vesicle to digest its contents

Identify the 2 types of Endocytosis

1. Phagocytosis (cell-eating: solid materials, food particles)

2. Pinocytosis (cell-drinking: dissolved molecules)