Movement In and Out of Cells Flashcards
Define active transport
- movements of ions in or out of a cell
- through a semi-permeable membrane
- may be against a concentration gradient
- expends energy released in respiration
- carrier proteins pick up specific molecules to transport
Define osmosis
- diffusion of liquid molecules
- from a region of high water potential to low water potential
- down a concentration gradient
- through a partially permeable membrane
Define crenation
Shrinking of an animal cell via osmosis
Define lysis
Bursting an animal cell via osmosis
Define plasmolysed
A plant cell that has lost water to the point where the cell membrane is pulled away from the inner cell wall
Define flaccid
A plant cell gone limp due to a reduction of pressure from within the cell
Define turgid
A plant cell fully inflated with water
Effect of distilled water solution on plant and animal cells after being kept in a saline solution
Plant cells become turgid, animal cells undergo lysis
Define diffusion
- net movement of molecules
- from high concentration to low concentration
- down a concentration gradient
- until equilibrium is reached
- result of random movement
Define hypertonic
A solution that has higher water potential than the cell placed in it
Define hypotonic
A solution that has higher water potential than the cell placed in it
Explain the mechanism of water movement from the roots up the tree to the leaves.
- Transpiration
- Creates negative pressure
- Water potential gradient
- Osmosis into leaf cells
- Continuous column of water
- Cohesion of water molecules
- Adhesion of water to xylem
- Water evaporates into airspaces
- Water vapour diffuses out through stomata
- Root pressure
Factors affecting transpiration
- temperature
- humidity
- wind speed
Describe the process of transpiration:
- Diffusion/osmosis causing movement from cell to air spaces
- Water moves through cell wall/membrane
- Evaporates to air spaces
- Water vapour moves out through stomata
