Movement in and out of cells Flashcards
Define diffusion
The movement of particles from a higher concentration to a lower concentration down the concentration gradient.
Define osmosis
The movement of water molecules across a partially permeable membrane from an area of higher water concentration to an area of lower water concentration.
Define active transport
Active transport is the movement of particles against a concentration gradient, using energy transferred during respiration.
Volume calculation
Volume=length x width x height
Area calculation
length x width
Function of the lungs
to transfer oxygen to the blood and to remove waste carbon dioxide from it.
What are alveoli
Little air spaces in the lungs where gas exchange takes place
Adaptions of alveoli
- An enormous surface area
- A moist lining for dissolving gases
- Very thin walls
- A good blood supply
What are villi
little projections covering the small intestine which increase the surface area so that digested food is absorbed much quicker into the blood.
Villi adaptations
- A single layer of surface cells
- A very good blood supply to assist quick absorption.
How does carbon dioxide enter the leaf
Carbon dioxide diffuses into the air spaces in the leaf, then diffuses into cells where photosynthesis happens.
What are stomata
tiny holes in the leaf which carbon dioxide diffuses in through.
Where is water vapour lost mostly in the leaf
Through the stomata
What controls the stomata to open and close
Guard cells
