Download File

Weekly Plan 18
Enzyme action 1
Student book links
 2.1.18
 2.1.19
 2.1.20
Specification links
 2.1.3 (a)-(c)
Link to GCSE specification
Suggested time allowed:
 Enzymes
 Digestion
 Nutrition
Four hours
Lesson time allocated:
Suggested teaching order
Weekly learning outcomes
Students should be able to:
 State that enzymes are globular proteins, with a specific tertiary structure, which catalyse metabolic
reactions in living organisms.
 State that enzyme action may be intracellular or extracellular.
 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.
1.
2.
3.
4.
5.
6.
Enzymes as globular proteins with an active site
Enzymes as catalysts and features of catalysts
Roles and locations of enzymes
Lock and key and induced fit
Effect on activation energy
Effect of mutations on enzyme structure
Key words
How science works
Enzyme. Tertiary structure. Metabolism. Globular protein. Primary structure. Amino acid.
Protein. Secondary structure. Hydrophobic. Hydrophilic. Catalyst. Complementary. Substrate.
Active site. Secondary structure. Glycosidic bond. Ester bond. Peptide bond. Respiration.
Photosynthesis. Maltose. Glucose. Monomer. ATP. Glycogen. Protease. Extracellular.
Intracellular. Metabolism. Endotherm. Optimum temperature. Heterotroph. Mitochondria.
Vesicle. Carbohydrate. Lipid. Fatty acid. Glycerol. Endocytosis. Lysosome. Lock and key
hypothesis. Induced fit hypothesis. Covalent bond. Activation energy. Hydrolysis. Metabolism.
Enzyme–substrate complex. Enzyme–product complex. DNA. Mutation.
 HSW 1: Using models
 HSW 3 & 6: Solving scientific problems designing washing
powder
Learning styles (S = Starter activities, M = Main activities, P = Plenary activities)
ICT activities
Kinaesthetic
Activity
Activity M1&M3
Activity P1&P3




Interpersonal
Activity S1–S2
Activity M1&M3
Activity P1–P3
Auditory
Activity S1–S2
Activity M1&M3
Activity P1–P3
Visual
Activity S1–S3
Activity M1–M3
Activity P1&P3
Animation: Enzyme specificity
Animation: What is an enzyme?
Animation: Enzyme shape
Use of Internet for Homework suggestions section
© Pearson Education Ltd 2008
This document may have been altered from the original
1
Weekly Plan 18
Suggested starter activities
Equipment
Teacher notes
1. Make two jellies before the lesson. One with fresh
pineapple incorporated and one without. The pineapple jelly
doesn’t set. Also make one jelly with tinned pineapple, which
does set.
Jelly, fresh pineapple, tinned pineapple,
bowls. You may also want to try kiwi,
mango or papaya.
Pineapples and some other fruits contain an enzyme called
bromelin that digests the gelatine. Use as basis for
discussion. Ask them why the jelly made with tinned
pineapple set and why many meat casseroles (e.g.
Moroccan cookery) involve cooking the meat slowly with
fresh fruit. What does that tell us about the optimum
temperature/ heat stability of the enzymes in the fruit?
2. Divide the class into groups with the topics: structure;
examples; and applications.
Each group speaks for 30 seconds on their topic in relation
to enzymes.
3. Demonstrate catalysis using manganese dioxide (catalyst)
and hydrogen peroxide: 2H2O2  2H20 + O2.
Hydrogen peroxide, boiling tube,
manganese dioxide
Try this before the lesson and take suitable precautions.
Suggested main activities
Equipment
Teacher notes
1. In groups, carry out an enzyme-controlled reaction.
Worksheet: Enzyme-controlled reaction
Use this as a context for introducing ideas of enzyme–
substrate complex, reactants and products.
2. Distribute diagrams of an enzyme colliding with a substrate
through to the products being formed. Students must
summarise the stages as a series of bullet points.
Diagrams of stages of enzyme action
3. In groups, make models of enzyme action to represent
induced fit.
Model-making equipment: sponges; card;
plastic bottles; bubble wrap; polystyrene
etc.
Suggested plenary activities
Equipment
1. Students must match enzymes with the reactions they
catalyse. This is well suited to a card-sort activity.
Cards with enzyme names and
corresponding reactions
2. Give students a series of statements about enzymes. They
must vote whether they are true or false
Create set of true/false cards about
enzymes
3. Give students a series of cards to play snap with. A snap
pair consists of a diagram on one card and a corresponding
explanation on the other.
Make set of 20 cards as described
Teacher notes
You should make 10 cards with diagrams and 10 cards with
corresponding explanations.
© Pearson Education Ltd 2008
This document may have been altered from the original
2
Weekly Plan 18
Homework suggestions
 Make a study stack about the mechanism of enzyme action. Notes: Enzymes 'study stack'
 Adopt the role of an enzyme and write a blog, describing what you do during catalysis.
 Produce a cartoon strip with written commentary of what happens during phagocytosis, providing details of enzyme action.
Cross-curriculum links
 Chemistry – biochemistry of enzymes and kinetic theory
Extension ideas
 Students write a comprehension exercise. The questions should pick out the relevant information from the Wikipedia entry on catalysis.
 Students design their own biological washing power. Worksheet: Design your own washing powder
Potential misconceptions
 Although the lock and key model is an obvious staging post, ensure that students can distinguish between it and the induced fit model.
 It is useful to relate the structure of an enzyme and the specificity of the active site back to more general ideas about protein structure.
 The idea of activation energy is very abstract. Using an explanation involving a transition state is usually most effective.
Notes
The web links referred to here are some that the author has found personally helpful but are not intended to be a comprehensive list, many other
good resources exist.
© Pearson Education Ltd 2008
This document may have been altered from the original
3