1.10 Exchanging Materials

Question 1

Surface area to volume ratio

Answer 1

The size lf the surface area of the organism compared to its volume.
-calculated by finding the volume and the surface area and writing the ratio in the smallest whole numbers
-if this is large the organism is less likely to require specialised exchange surfaces and a transport system because rate of diffusion is sufficient in supplying and removing the necessary gases

Question 2

Single celled organisms and multicellular organisms

Answer 2

-can use diffusion to transport molecules into their body from the air-this is because they have large surface area to volume ratio. Due to their low metabollic demands, doffusion across the surface of the organism is sufficient enough to meet its needs.

-multicellular organims the surface area to volume ratio is dmall so they cannot rely om diffusion alone. Instesd,surfaces and organ systems have a number of adaptations that allows molecules to be transportedbin and out of cells

Question 3

Adaptation, why?

Answer 3

Having a large surface area- the greater the surface area the more particles can move through,resulting in a faster rate of diffusion