Diffusion, exchange surfaces, osmosis and active transport Flashcards
What is diffusion?
The spreading out of particles from an area of high concentration to an area of low concentration.
What factors affect the rate of diffusion?
Temperature
Surface area of the membrane
Concentration gradient
What is an exchange surface?
A part of an organism where substances are exchanged with the environment.
How are exchange surfaces adapted?
They have a thin membrane
They are 1 cell thick
Have a large surface area
Have lots of blood vessels/large blood supply
Are often ventilated
What are examples of exchange surfaces?
The small intestine exchanges nutrients between digested food and the blood
The lungs exchange carbon dioxide and oxygen between the blood and air
What is osmosis?
The diffusion of water particles from an area of high concentration to an area of low concentration across a partially permeable membrane.
What is active transport?
The net movement of particles from an area of low concentration to an area of high concentration using energy.
What are examples of active transport in humans and plants?
Sugar absorption in human gut
Mineral absorption in plants
