Download ENZYMES

ENZYMES
Enzymes
• Are Proteins
• Chemical CATALYSTS which speed up the
rate of chemical reactions by lowering the
activation energy - the energy needed to
get a reaction started
• Chemical Reactions = a process that
changes or transforms one set of
chemicals into another
Chemical Reactions
• Reactants =
Substrates
• Reactants (substrates)
are elements or
chemicals which
ENTER into the
reaction (on the DULL
side of the arrow)
• CO2 + H2O--->H2CO3
(carbonic acid)
• Products - elements or
compounds produced
(made or formed) by the
reaction (on the pointed
side of the arrow)
• CO2 + H2O ---> H2CO3
(carbonic acid)
Energy
• Reactants must collide with enough energy to
break old bonds and form new ones
• Some reactions RELEASE energy ie: 2H2+O2--->
2H2O + heat
• Some reactions ABSORB energy ie:
2H2O----> 2H2+O2 (energy is needed - light
reactions of photosynthesis)
• Energy is stored in the bonds between molecules
• Matter and energy must be conserved - some
reactions happen slowly, others happen quickly
Enzymes
• Provide a SITE (place)
where reactants
(substrates) can be
brought together to
react –
• the SITE reduces the
energy needed
• ACTIVE SITE - is a
specific shape so that
only those substrates
will fit = lock & key
Factors affecting enzyme
reaction rates
• pH - some work better in low pH ie: pepsin
in stomach
• Temperature - most enzymes work at
normal body temperature (37 degrees
Celsius or 98 degrees F)
• Regulatory molecules - switch enzymes
on or off
Factors affecting enzyme
reaction rates
• Enzyme concentration - the amount of
enzymes available
• Substrate concentration - the amount
of substrates needed to be worked on
• Denaturing - changes in the shape of
the protein (enzyme) or the active site
ie - frying an egg