Protein and enzymes c: Enzyme specificity
Recap
 Draw lolly stick/name/number out of hat to select one
person in class to recap what was talked about/learned
in the last lesson
 Warning! Be on your guard it may be your turn next!!
What are we learning today?
We are learning to:
 Give examples of enzyme controlled reactions to
illustrate enzyme specificity
Success criteria:
 An enzyme is specific to one substrate
 Give examples
What does enzyme specificity mean?
 The substance an enzyme acts on is the
SUBSTRATE.
 What is made in the reaction is called the
PRODUCT.
Experiment 2
 Aim: to find out what is meant by enzyme specificity
using enzymes and various substrates
A
Amylase and
starch test for
sugar using
clinistix
B
Amylase and
hydrogen
peroxide test
for oxygen
using glowing
splint
C
Catalase and
hydrogen
peroxide test
for oxygen
using glowing
splint
D
Catalase and
starch test for
sugar using
clinistix
Experiment conclusions
 Catalase only acts on hydrogen peroxide
 Amylase only acts on starch
 Enzymes are SPECIFIC
 This means that they only work on one
substrate
 Enzymes are complimentary in shape to
their substrate
Enzymes are Specific
 KEYS
are SPECIFIC
to LOCKS
 ENZYMES
are SPECIFIC
to SUBSTRATES
hydrogen
peroxide
water
oxygen
Enzymes are Specific
 Catalase (enzyme) will only act on hydrogen peroxide
(substrate)
hydrogen
peroxide
Starch
water
oxygen
No reaction
No products formed
Enzymes are Specific
 Only catalase will catalyse the breakdown of
hydrogen peroxide
hydrogen
peroxide
amylase
hydrogen
peroxide
water
oxygen
No reaction
No products formed
Enzymes are Specific
 Remember:
 Enzymes are specific because of their shape.
hydrogen
peroxide
amylase
hydrogen
peroxide
water
oxygen
No reaction
No products formed
The shape of amylase is different to
catalase so it will not catalyse the
reaction.
The Active Site
 Where a substrate
attaches to an enzyme is
called the active site
 The active site is where
the reaction occurs
 The active site is
complimentary to the
shape of the substrate
 The amino acid sequence
determines the shape of
the active site
bbcbitesize Standard Grade Biology
Summary
 Exit ticket
 Draw a diagram (not like one you have seen today) to
show what you understand about enzyme specificity