Topic 2: Cell Physiology 1 - Membrane Transport (Active) Flashcards
What do active processes require?
energy (ATP)
What is active transport?
- substances move against CG (low to high)
What are the types of active processes?
- active transport
- vesicular transport
Active TRANSPORT always requires ____ ____.
protein carriers
What are the two types of active transport?
- primary
- secondary
What is primary active transport? (2)
- molecular pumps
- ATP breakdown is directly part of the transport process
What is an example of primary active transport?
- sodium potassium - ATPase pump
- 3 sodium out, 2 K+ in per ATP
What is secondary active transport?
- cotransport (use of ATP is indirect)
ex. glucose entry at small intestine
Why is glucose entry into the small intestine secondary active transport? (4)
- Na+ gradient established by Na+/K+ - ATPase
- glucose and Na+ both must bind to carrier
- cotransported into the cell
- Na+ moving down its CG drives in glucose against its CG (transport step)
What is vesicular transport?
- substance is surrounded by a membrane within a cell (vesicle)
What are the two types of vesicular transport?
Endocytosis and exocytosis
What is endocytosis?
Movement into a cell
What are the two types of endocytosis?
Phagocytosis and pinocytosis
What is phagocytosis? (2)
- large items into cell (ex. Bacteria)
- “cell eating”
What is pinocytosis? (2)
- fluids (and dissolved substances)
- “cell drinking”
What is exocytosis?
Movement out of cell
What do vesicles in exocytosis contain? (3)
- Hormones
- Enzymes
- Neurotransmitters etc.
What happens in exocytosis? (2)
- vesicles fuse with cell membrane, releasing contents into ECF
- triggered by a rise in cytosolic Ca++
