3.1.2a) The need for transport systems in multicellular organisms

Question 1

Metabolic demands

Answer 1

Demands are for oxygen and food are high & lots of waste products are produced
Diffusion over long distances is not enough to supply quantities needed

Question 2

Surface area to volume (SA:V) ratio

Answer 2

SA:V gets smaller as the organism gets bigger
Diffusion distance gets bigger but the amount of SA available to absorb or remove substances become relatively smaller

Question 3

Biological molecules (e.g. hormones or enzymes)

Answer 3

May be made in one place but is needed in another