Unit 1 Section 4: Exchange Surfaces

Question 1

Smaller organism’s surface area to colume ratio is _____ than a larger organism’s

Answer 1

Bigger

Question 2

single celled organisms

Answer 2

substances can diffuse directly into or out of the cell across the cell surface membrane. the diffusion rate is quicker because of the small diffusion distance and because they have a high surface area:Volume ratio.

Question 3

multi-cellular organisms

Answer 3

diffusion across the outer membrane is slow for two resons:

*some cells are deep within the body - there’s a big difference between them and the outside world