Respiration is just breathing right?
Wrong! Respiration is the chemical
process that supplies the body with
energy for all other life processes.
Growth and repair of cells, muscle
contraction, protein synthesis, sending
nerve impulses, absorbing molecules and
active transport to name just a few.
It happens in all living cells. Not just
animal cells but also blood cells. There
are two types of respiration: aerobic and
anaerobic respiration. Aerobic means with
air and so needs oxygen.
Whereas anaerobic respiration doesn't
need oxygen.
Let's start by looking at aerobic
respiration. Aerobic respiration
releases energy in cells by breaking
down food substances whilst in the
presence of oxygen. It is represented by
this simplified equation...
But don't forget the energy which is released. Glucose is broken down by oxygen to release the
byproducts of carbon dioxide and water.
Energy is released which is then used to
make a special energy molecule called
ATP. ATP is how energy is stored for
later use by the body. Aerobic
respiration happens all the time in all
cells, usually in the mitochondria.
Animals get the oxygen needed from the
air, through their ventilation systems.
Plants get their oxygen from the air
through the stomata. Do you remember how photosynthesis works?
Compare these two equations...
You can hopefully see that aerobic
respiration works in the opposite way to
photosynthesis. Plants produce food by
photosynthesis and then through
respiration release energy from it.
But don't be confused: whilst plants do release oxygen as a byproduct of photosynthesis
they don't necessarily take in this
oxygen for respiration. They just take in
any oxygen from the air. Plants respire
throughout the day and night as do
animals. But they only photosynthesize
during the day when there is light
available. So this is how aerobic, or with
air, respiration works. You just need to
remember that glucose is broken down
in the presence of oxygen, to release
carbon dioxide + water and energy. In the
next video we will have a look at
anaerobic respiration and how it differs.
