Slides in this set
Active transport is the travel of
substances against the concentration
gradient (low to high).
This means that the process is active,
and it needs energy, unlike diffusion and
osmosis which are passive.…read more
Exchange in the lungs
The lungs exchange oxygen (needed for
aerobic respiration) and carbon dioxide
(waste product of aerobic respiration) with
Large surface area, helped by the alveoli
(air sacs), moist surfaces, thin surfaces, all
help diffusion take place quicker.
The air sacs also have a good blood supply
regarding the capillaries to help diffusion.…read more
Exchange in the gut
The food we eat is broken down into small
soluble molecules (molecules which
dissolve), and these are absorbed into the
Villi, the finger like projections in the gut
greatly increase surface area for absorption
to take place.
Food is absorbed by diffusion, when there
is a lower concentration of that food particle
in the blood, and it is absorbed by active
transport, when there is a higher
concentration of that molecule in the blood.…read more
Exchange in other organisms
All living organisms have similar
adaptations so as to help diffusion, large
surface areas, moist, gases transported
quickly away to keep a high concentration
gradient, membranes which gases diffuse
across are thin.
Fish exchange oxygen through gills
Frogs exchange oxygen through their skin
Insects exchange oxygen through holes in
the sides of their bodies.…read more
Exchange in plants
Gases diffuse out of holes in the leaf
called the `stomata'.
Oxygen is needed for respiration and is
a waste product of photosynthesis.
Carbon Dioxide is needed for
photosynthesis and is a waste product
The net movement of gases depends on
which process is taking place more