Biology - Exchange surfaces

How does an organism exchange surfaces with its environment?

SA : V

How do you work out the area of a surface?

Length X Width

How do you work out the volume?

Length X Width X Height

How can single celled organisms diffuse straight inti or out of the cell across the cell membrane?

Because they have a large Surface area compared to their Volume

Is a multicellular organisms surface area of volume larger?

Smaller surface area compared to their volume

How are exchange surfaces adapted to maximise effectiveness?

Thin membrane so substances only have a short distance to diffuse, Large surface area so lots of substances can diffuse at once, Lots of blood vessels (in animals) to get things in and out of the blood quickly, Gas exchange surfaces (in animals) are often ventilated so air moves in and out.