What four things are exchanged between an organism and its environment?
Respiratory gases like Oxygen and CO2, Nutrients like glucose, fatty acids, amino acids, vitamins/minerals, Excretory products - urea, CO2, and Heat.
1 of 5
What are the two ways that exchange takes place?
Passively - diffusion and osmosis. Actively - with energy - Active Transport.
2 of 5
Name the five features of specialised exchange surfaces and explain what they contribute to.
Large SA: VOL ratio - fast diff rate. Thin - short diff path - fast diff rate. Partially permeable membrane - selective, easy diffusion. Movement of external medium - air - maintain conc grad. Movement of internal medium - blood- maintain conc grad.
3 of 5
Describe how to work out SA: VOL ratio.
Surface area = length squared. May need to multiply by number of faces if shape is 3D. Volume = length cubed. Divide surface area by volume.
4 of 5
How have organisms evolved to overcome slow diffusion from large volume?
Flattened shape, no cell ever far from surface. Specialised exchange surface with large areas to increase SA: VOL ratio. Lungs in mammals, gills in fish.
5 of 5
Other cards in this set
Card 2
Front
What are the two ways that exchange takes place?
Back
Passively - diffusion and osmosis. Actively - with energy - Active Transport.
Card 3
Front
Name the five features of specialised exchange surfaces and explain what they contribute to.
Back
Card 4
Front
Describe how to work out SA: VOL ratio.
Back
Card 5
Front
How have organisms evolved to overcome slow diffusion from large volume?
Comments
No comments have yet been made