B3: Exchanging Materials (Humans, Plants and Animals)

This is a document mainly for students taking AQA Additional Science. It contains information on exchanging materials in humans, animals and plants from the B3 (biology) specification. I hope this helps you to revise! Please rate and comment on how to improve :) Also, i have a study group called AQA Additional Science where we discuss topics such as this one and many more. Feel free to become a member, the more the merrier!

HideShow resource information
  • Created by: I P B
  • Created on: 06-03-10 14:27
Preview of B3: Exchanging Materials (Humans, Plants and Animals)

First 141 words of the document:

B3: Exchange in Materials
The cells in animals and plants all need oxygen to be able to
release energy for the jobs they do. They all produce carbon
dioxide as a waste product.
Dissolved substances move by diffusion (look back at B2 for
more information)
Active Transport
Substances are sometimes absorbed against a concentration
gradient. This requires the use of energy from respiration. The
process is called active transport.
It enables cells to absorb ions from very dilute solutions. Other
substances, such as sugar and ions, can also pass through cell
Exchanging Materials in humans
Many organ systems are specialised for exchanging materials.
the surface area of the lungs is increased by the alveoli
and that of the small intestine by villi.

Other pages in this set

Page 2

Preview of page 2

Here's a taster:

The lungs are in the upper part of the body (thorax) protected by
the ribcage and separated from the lower part of the body
(abdomen) by the diaphragm.
The breathing system takes air into and out of the body so that
oxygen from the air can diffuse into the bloodstream and carbon
dioxide can diffuse out of the bloodstream into the air.…read more

Page 3

Preview of page 3

Here's a taster:

Exchanging Materials in plants
carbon dioxide enters leaf cells by diffusion
most of the water and mineral ions are absorbed by root hair
The surface area of the roots is
increased by root hairs and the
surface area of leaves by the
flattened shape and internal air
Plants have stomata to obtain
carbon dioxide from the
Plants lose water vapour from the
surface of their leaves. This loss of
water vapour is called transpiration.…read more

Page 4

Preview of page 4

Here's a taster:

The size of stomata is controlled by guard cells which surround
them. If plants lose water faster than it is replaced by the roots,
the stomata can close to prevent wilting.…read more

Page 5

Preview of page 5

Here's a taster:

In larger organisms which are more complex and have millions of
cells, there are different specialised exchange surfaces like the
villi in the small intestine or the alveoli in the lungs.…read more

Page 6

Preview of page 6


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all resources »