Membrane Transport - BIO 102 CONTENT Flashcards
Isotonic Solution
- Concentration of water: equal on both sides
- No net movement of water
- No change in the overall cell
- Ideal condition for most living cells
Example of an isotonic solution?
Eye drops are often isotonic to tears
Hypotonic Solutions
Less solute in the liquid around the cell
Hypotonic Solutions: Concentration of Water
Greater on the outside of the cell
Hypotonic Solution: Results
- Animal cells swell and burst
- Plant cells get turgid
Hypotonic Solution: Net Movement
Net movement of water is into the cell
Hypotonic solutions examples
- Why we put flowers in water
- Why pure water is never given by IV
Hypertonic Solutions
More solute in liquid around the cell
Hypertonic Solutions: Concentration of water
Greater on the inside of the cell
Hypertonic Solutions: Net movement
Net movement of water is out of the cell
Hypertonic Solutions: Results
- Animal cells shrivel and eventually die
- Plant cells undergo plasmolysis and wilting
Hypertonic Solution example
Why you shouldn’t drink seawater
Active Transport Definition
- Movement of molecules from an area of low concentration to an area of high concentration
- Against the concentration gradient
- Requires the use of energy (usually ATP)
- Uses membrane proteins similar to facilitated diffusion
Cotransport
Coupling the transport of the diffusion of one molecule down its electrochemical gradient with the transport of another molecule against its electrochemical gradient
What are the two types of cotransport?
- Symport Transport
- Antiport
Symport Transport
- Transported solute moves in the same direction as the gradient of the driving ion
Antiport
- Transported solute moves in the opposite direction to the gradient of the driving ion
Bulk Transport
- Export or import of large molecules across membranes via vesicles
2 types of bulk transport
- Endocytosis
- Exocytosis
Endocytosis
- The bulk transport of particles and large molecules of material into a cell
3 different types of endocytosis
- Pinocytosis
- Phagocytosis
- Receptor assisted endocytosis
Pinocytosis
- “cell drinking”
- Takes in small particles of solute along with a small drop of extracellular fluid when the cell membrane pinches in and forms a vesicle
Phagocytosis
- “cell eating”
- Takes in large particles or whole cells by engulfing them
- The cell send out extensions of cytoplasm which surround and engulf the target particles
- Usually involves one cell pursuing another
Receptor Assisted Endocytosis
- “Cell dieting”
- Specific molecules attach to membrane receptor proteins
- Receptors are specific for one type of molecule only
Exocytosis
- Bulk transport of particles and large molecules out of the cell
- Requires energy
How does exocytosis work?
- A vacuole in the cell moves towards the cell membrane and fuses with it, it expels the contents of the vacuole into the extracellular fluid