Enzymes are protein catalysts that speed up chemical reactions without being used up. They work best within certain temperature and pH ranges - human enzymes typically have an optimal temperature around 40 degrees Celsius while plant enzymes work best around 25 degrees. Both can become denatured and non-functional outside their optimal conditions. The "lock and key" and "induced fit" models describe how enzymes position their active sites to selectively bind with substrate molecules for catalysis.

1. BY:
PUTRY ENDAHSARI

2. Enzymes are proteins that function
as a biological catalyst that speeds
up a chemical reaction but isn’t
changed by the reaction.

3. affect by the change in temperature
enzymes in humans have
optimum temperatures of
around 40 degrees.
Plants have enzymes with
optimum temperature of
about 25 degrees.
most active
below
the activity of the enzyme
decreases until it becomes
inactive at low temperatures.
above
the enzyme becomes denatured
and can no longer work.

4. affect by the change in ph
Each enzyme has an
optimum pH, if this
pH changes, the
shape of the active
site of the enzyme is
changed, thus the
substrate will not be
able to fit in it, and
the enzyme
becomes useless.
ph
1
7
14
Acidic:Neutral:Alk

5. LOCK & KEY THEORY
Lock = enzyme
Key = substrate
Only the correctly
sized key
(substrate) fits
into the key hole
(active site) of the
lock (enzyme).

6. INDUCED FIT
MODEL
To describe that only the
proper substrate is
capable of inducing the
proper alignment of the
active site that will
enable the enzyme to
perform its catalytic
function.

7. Breaking large
molecules into small ones(catabolism->
produce energy)
Building up large
molecules from small ones(anabolism->
require energy)
Converting one small molecule into
another
Enzymatic
reaction