Exchanging Substances Flashcards
Say an example of an organism exchange substances with their environment
Cells remove Urea to the environment around them (Waste product produced from the breakdown proteins). Cells take in Oxygen and Glucose from the environment.
Why does surface area:volume ratio collegiate to organisms exchange substances with its environment
how easy it is for an organism to exchange substances with its environment depends on the organisms surface area : volume ratio.
How do single celled organisms have exchange substances
Gases and dissolved substances can diffuse directly into the cell across the cell membrane because it has a large surface area to volume ratio, so enough substances can be exchanged across the membrane to supply the volume of the cell.
How do multi cellular organisms do exchange substances
Has a smaller surface area to volume ratio, this means that not enough substances can diffuse from their outside surface to supply their entire volume.
If multi cellular organisms can’t have enough substances diffuse from their outside surface to supply their entire volume, what do they do?
They need some sort of exchange surface for efficient diffusion.
How is it adapted for maximum efficiency
- Thin Membrane - Short Distance to Diffuse
- Large Surface Area - Lots of substance diffuse at once
- Exchange Surfaces - Animals —> lots of blood vessels to get stuff in an out of the blood quicker
- Gas exchange surface - Animal —> ventilated (air moves in and out)
How does lungs do gas exchange
As it takes in oxygen and takes away carbon dioxide
How do lungs maximise their effectiveness of gas exchange
They have millions of alveoli, which has an enormous surface area, moist lining dissolving gases, thin walls and good blood supply.
What thing in the small intestines provides big surface area
Villi increases surface area which makes digesting food quicker. It also has a single layer of surface cells which helps it do it quicker. Very good blood supply, assists quick absorption.
