Surface Area To Volume Ratio

Question 1

Why do larger organisms have smaller surface areas

Answer 1

Their volume increases in size faster than their surface area

Question 2

Describe smaller organisms surface area to volume ratios

Answer 2

• smaller organisms have larger surface areas compared to their small volume, allowing efficient exchange of gasses

Question 3

How do you calculate surface area to volume ratios

Answer 3

Surface area divided by volume

Question 4

What are features of cells to increase their surface area

Answer 4

• A flattened shape
• Specialised exchange surfaces (root hair, folded membranes) with large areas to increase their SA:V ratios
• Thin membranes to ensure the diffusion distance is short
• A good supply/ventilation of blood to maintain a steep conc gradient in places such as the aveoli

Question 5

What other characteristics of exchange surfaces to increase the SA:V ratio of organisms

Answer 5

• thin membranes
• selectively permeable membranes
• movement of external mediums such as air
• A transport system to ensure the movement of internal mediums