The Gryphon School Science Department
OCR AS Level Biology Scheme of Work
Unit F212: Molecules, Biodiversity, Food and Health
MODULE 1:
Topic 2.1.3
Lesson
1
Biological Molecules
Enzymes
Objectives
(a) state that enzymes are
globular proteins, with a
specific tertiary structure,
which catalyse metabolic
reactions in living
organisms;
(b) state that enzyme action
may be intracellular or
extracellular;
(c) describe, with the aid of
diagrams, the mechanism
of action of enzyme
molecules, with reference
to specificity, active site,
lock and key hypothesis,
induced-fit hypothesis,
enzyme-substrate complex,
enzyme-product complex
(and lowering of activation
energy – not covered this
lesson);
Lesson Activities
Resources
STARTER – Discuss in small groups what students think
enzymes are, giving examples etc.
MAIN –
1. Recap the structure of proteins (2.1.1 Biological
Biology 1
Molecules) and link into structure of enzymes
2. Discuss and then explain how enzymes work –
perhaps model using students. Link to intra- and
extra-cellular enzymes
3. Students to devise their own way of explaining
what enzymes are and how they work (eg: a mini
play or presentation or summary sheet) using
Biology 1 p.131-132 and present this to the rest
of the class
4. Make own notes based on the work covered today
(including key words – intracellular, extracellular,
globular, active site, enzyme, substrate, complex,
induced fit, specific, products, lock and key).
PLENARY – recap objectives and discuss what students
have learnt today. Judge presentations.
H/W – Research the names of two intracellular and two
extracellular enzymes and their functions
G&T – find out about the 6 enzyme subclasses (search
Access to the
International Union of Biochemists – enzymes on the
internet/library
internet) and what their functions are.
-1-
Notes
The 6 classes are:
Oxidoreductases,
transferases, hydrolases,
lyases, isomerases and
The Gryphon School Science Department
OCR AS Level Biology Scheme of Work
Unit F212: Molecules, Biodiversity, Food and Health
2
(c) describe, with the aid of
diagrams, the mechanism
of action of enzyme
molecules, with reference
to specificity, active site,
lock and key hypothesis,
induced-fit hypothesis,
enzyme-substrate complex,
enzyme-product complex
and lowering of activation
energy;
(d) describe and explain
the effects of pH,
temperature, enzyme
concentration and substrate
concentration on enzyme
activity;
Support activities – use of the text book and support from
other students during ‘practical’ activity and OCR Revise
AS Biology Heinemann text book p.54-55
STARTER – share the names of intracellular and
extracellular enzymes students have found for their
homework and recap the difference between these two
types, how enzymes work and why we need them
MAIN –
1. What is activation energy? Show students a
boiling tube of hydrogen. It is very reactive – it
reacts explosively with oxygen in the air but not
until there is a spark – why? Discuss.
Demonstrate ‘squeaky pop’ test! You need a
certain amount of energy to get the reaction
going!
2. In YOUTUBE, type in ‘activation energy’ and
watch the first video (1 min 16 seconds). Use this
and Biology 1 Figure 9.3 p.133 to make own
notes on activation energy
3. How does activation energy link in to enzymes?
They lower it and consequently temperature
would not have to be so high (better for
mammals).
4. How else can you speed up a chemical reaction
which includes enzymes? Discuss. Link in to
specification objectives (c) using text book pages
135-138
PLENARY – hand out and discuss homework – Chapter
3 Enzymes Worksheet: Enzyme prose questions
-2-
OCR Revise AS Biology
Heinemann text book
ligases
Boiling tube of hydrogen
Splint and matches
Biology 1
Copy and paste the
following link http://www.youtube.
com/watch?v=
VbIaK6PLrRM
Worksheet found in file
called Chapter 3 p.035060.pdf
‘Standard level’
homework will
require copies of the
mark scheme as well
The Gryphon School Science Department
OCR AS Level Biology Scheme of Work
Unit F212: Molecules, Biodiversity, Food and Health
3
H/W – Complete worksheet
G&T – find out about experimental procedures linked to
specification objective (c)
Support activities – ‘Standard level’ homework set and
use of text book, OCR Revise AS Biology Heinemann
text book p.54-57
(e) describe how the effects STARTER – hand in homework. Discuss the effect of
of pH, temperature,
temperature on enzyme activity. Use key words such as
enzyme concentration and
denaturing and optimum temperature. Recall that
substrate concentration on
optimum temperature depends upon the enzyme.
enzyme activity can be
MAIN –
investigated
1. Introduce trypsin as an enzyme that hydrolyses
experimentally;
casein in milk – when this protein is hydrolysed,
the milk will appear translucent. The aim today
is to find the optimum temperature for trypsin.
2. Quick discussion on a suitable practical method
to determine the activity of trypsin at different
temperatures
3. Complete Practical 2 – Investigating the effect of
temperature on the activity of trypsin and
complete the associated questions on the
worksheet.
4. Pack away all equipment
PLENARY – discuss the results that students have found
and critically evaluate the practical procedure and
students progress during the lesson. Link this in to
Practical Skills as associated with Unit F213 and how
students need to work/behave in practical assessments.
H/W – Complete Practical 2 worksheet
-3-
Biology 1, access to library
or internet
OCR Revise AS Biology
Heinemann text book
Per group (this is slightly
different to that on the worksheet
as the students should wash up
their own apparatus and re-use
it!)
Practical 2 worksheet
4 x 5 cm3 syringes
6 boiling tubes
Stickers (for labelling)
Test tube rack and holder
Thermometer, goggles
Tripod, Bunsen, Gauze,
Heatproof mat, matches
Large beaker (250 cm3)
Stirring rod, stop clock
50 cm3 of 4% milk powder
solution
30 cm3 of 0.5% trypsin sol.
10 cm3 of 0.1 moldm-3 HCl
10 cm3 distilled water
Calculator
Alternatively have
some water baths set
up at temperatures
between 20°C and
70°C (this will save
time!)
The Gryphon School Science Department
OCR AS Level Biology Scheme of Work
Unit F212: Molecules, Biodiversity, Food and Health
4
G&T – What is the effect of copper (II) sulphate (a noncompetitive inhibitor of trypsin) on activity at 40°C?
Use Practical Guidance notes for this activity
Support activities – put students in groups where they
will be supported by other students, OCR AS Biology
Heinemann text book (NOT the revision one!) p.128-9
(e) describe how the effects STARTER – What things affect the rate at which
of pH, temperature,
enzymes work? Link back to notes from Lesson 2.
enzyme concentration and
Discuss what we did in Lesson 3.
substrate concentration on
MAIN –
enzyme activity can be
1. What is the effect of pH on enzyme activity and
investigated
why? Discuss and think about how to investigate
experimentally;
this
2. Complete Practical 6 – Investigating the effect of
pH on the activity of Amylase and the associated
questions (recalling the importance of
experimental procedure and the way students
work with respect to practical marks in the future)
3. Pack away equipment
4. Discuss what you have found out (draw a mini
conclusion) and critically assess the practical –
how could we improve this?
5. Discuss how you could measure the rate of a
reaction with reference to hydrogen peroxide
being broken down by catalase (Biology 1 p.134)
PLENARY – answer SAQ 1 (page 134) and Self assess
the answer
H/W – Review our learning so far – re-read relevant
-4-
Graph paper
Practical Guidance notes
and further equipment as
detailed there.
OCR AS Biology
Heinemann text book
Per group
Practical 6 worksheet
5 boiling tubes, test tube
rack, 3 x 5 cm3 syringes, a
pipette, spotting tile, UI
paper, goggles, stopwatch
30 cm3 of 1% starch sol.
10 cm3 of 1% amylase sol.
5 cm3 of 0.05 moldm-3
sodium carbonate solution
10 cm3 of 0.1 moldm-3
ethanoic acid
Iodine solution
Graph paper
Biology 1
The Gryphon School Science Department
OCR AS Level Biology Scheme of Work
Unit F212: Molecules, Biodiversity, Food and Health
5
(f) explain the effects of
competitive and noncompetitive inhibitors on
the rate of enzymecontrolled reactions, with
reference to both reversible
and non-reversible
inhibitors;
(h) state that metabolic
poisons may be enzyme
inhibitors, and describe the
action of one named
poison;
(i) state that some
medicinal drugs work by
inhibiting the activity of
enzymes (HSW6a).
pages of Biology 1 (p.131-138) and complete SAQ 2 & 4
G&T – complete SAQ 3 on p.136
Support activities – put students in groups where they
will be supported by other students, OCR AS Biology
Heinemann text book (NOT the revise one!) p.130-131
STARTER – Recap the lock and key hypothesis and how
enzymes work – can students recall their ‘plays’ from
Lesson 1?!
MAIN –
1. What is an inhibitor? How might it work? Link
to idea of competitive and non-competitive
inhibitor. Describe and explain how this works.
2. Get students to model competitive and noncompetitive inhibitors using the ‘play’ from the
starter as a starting point. Show to the rest of the
class. Bring in idea of reversible and nonreversible inhibition.
3. Why is it important to understand this? Does this
have an impact on you? Yes!!! Tell students
about some metabolic poisons and how they work
(eg: death cap mushroom and its effects, cyanide
– a reversible inhibitor of cytochrome oxidase,
neurotoxins which induce paralysis etc.) –
evolved by organisms for defence against attack!
4. Look at Figure 9.13 on page 139 and explain
what it shows.
5. Uses of inhibitors – search Enzyme inhibitors on
Wikipedia and it will detail information on uses
of inhibitors such as chemotherapy and
-5-
Biology 1
OCR AS Biology
Heinemann text book
You could complete this
lesson as a research lesson
in an ICT suite – there are
many interesting websites
on natural and man-made
toxins with relation to
enzyme inhibitors!
The Gryphon School Science Department
OCR AS Level Biology Scheme of Work
Unit F212: Molecules, Biodiversity, Food and Health
(g) explain the importance
of cofactors and
coenzymes in enzymecontrolled reactions;
6
anaesthetic etc.
PLENARY – key word bingo based on key words
covered so far in this topic
H/W – Describe the action of a named poison that is an
enzyme inhibitor
G&T – read extension on p.139 and use this as a basis to
find out about end product inhibition
Support activities – use of Biology 1 as support and OCR
AS Biology Heinemann text book (NOT the revision
one!) page 134-135 and p.138-139
STARTER – Read p. 140 Brown box on Leeches and
Blood clotting. Recap blood clotting from Year 11
Biology lessons. How do students feel about using
leeches in medicine?
MAIN –
1. Use Biology 1 p.140 to discuss what co-factors
and coenzymes are. Make own notes
2. Hand out Biofactsheet 43 – Factors affecting
enzyme activity and get students to read the
summary notes and highlight key parts.
3. Discuss the Practise questions at the bottom of
the Biofactsheet
4. Read the Summary box on page 141
5. Revise and review all of the ideas covered in this
topic
PLENARY – as a class (in discussion) answer Question
1 on page 141
H/W – Review and revise 2.1.3 Enzymes using notes and
Biofactsheet for a test next lesson
-6-
Access to the
internet/library
OCR AS Biology
Heinemann text book
Biology 1
Biofactsheet 43 Found as a file called
43_Enzyme Activity.pdf
Access to online version of
Biology 1 for answers
The Gryphon School Science Department
OCR AS Level Biology Scheme of Work
Unit F212: Molecules, Biodiversity, Food and Health
To review our learning
from Topic 2.1.3 Enzymes
7
G&T – try to answer Question 2 on page 142 and then
compare your answer critically to the answer given
Support activities – work in groups and use Biology 1
STARTER – Last minute revision – students to get into
exam style positions
MAIN –
1. Complete the End of chapter test in exam
conditions (40 minutes maximum) – complete on
lined paper
2. Swap exam papers and peer assess using the mark
scheme (hand out copies of the mark scheme –
work in small groups to mark the tests out of 38).
Each student to have a copy of the mark scheme
to keep for future reference.
PLENARY – Grade the exams A-E and collect in the
marks and grades
H/W – n/a
G&T – n/a
Support activities – n/a
-7-
Access to online version of
Biology 1
Biology 1
Class sets of End of chapter test
End of chapter test mark
scheme
Lined paper
Calculators