Cells have
thousands of
different chemical
reactions going on
inside them all the
time
Respiration
Respiration releases
energy for cells from
glucose. This can be aerobic
respiration, which needs
oxygen, or anaerobic
respiration, which does not.
Photosynthesis
Photosynthesis is a process used by plants and other
organised to convert light energy, normally from the Sun, into
energy that can be later released to fuel the organisms
activities.
Protein Synthesis
The production of
proteins in a cell
using base pairs.
These reactions
need to be
carefully
controlled- to get
the right amounts
of substance and
keep the organism
working properly.
You can usually make a reaction happen more quickly by
raising the temperature. This would speed up the useful
reactions but also the unwanted ones too... not good.
There's also a limit to how far you can raise the
temperature inside a living creature before the cells start
to get damaged,
So living things
produce Enzymes,
which act as biological
catalysts. A catalyst is
a substance that
speeds up a reaction,
without being changed
or used up in the
reaction itself.
Enzymes reduce
the need for high
temperatures
and we only have
enzymes to
speed up the
useful chemical
reactions in the
body.
Every different biological reaction has its own enzyme designed especially for it.
Each enzyme is coded for by a different gene,
and has a unique shape, which it needs to do its
job.