New
New
Year 10
AQA
Higher

Enzymes: function, structure and specificity

I can explain what an enzyme is and why the shape of an enzyme is important for how it works.

New
New
Year 10
AQA
Higher

Enzymes: function, structure and specificity

I can explain what an enzyme is and why the shape of an enzyme is important for how it works.

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Lesson details

Key learning points

  1. Enzymes are proteins that act as catalysts, speeding up chemical reactions.
  2. Without enzymes, many reactions would happen too slowly to support life.
  3. Enzymes catalyse reactions essential to life, including digestion and reactions in photosynthesis and respiration.
  4. Each enzyme has a 3D shape with an active site that a specific substrate fits into.
  5. The lock and key model to explain enzyme-substrate interactions.

Common misconception

That enzymes are used up in reactions, or that an enzyme can catalyse many different reactions.

Enzymes are not used up in the reactions that they catalyse, and that they can only catalyse one reaction, as explained by the lock and key hypothesis.

Keywords

  • Enzyme - A protein which acts as a biological catalyst.

  • Catalyst - A substance that speeds up the rate of a reaction without being used up.

  • Active site - The part of an enzyme where the substrate binds.

  • Substrate - The substance which is acted upon by the enzyme.

  • Model - Scientists use models as simpler representations of complex things and ideas.

If the part on activation energy is too complex, omit it from the lesson. Consider using plasticine modelling instead of drawing the labelled diagram, or having a number of padlocks and keys to try to sort out from each other.
Teacher tip

Licence

This content is © Oak National Academy Limited (2024), licensed on Open Government Licence version 3.0 except where otherwise stated. See Oak's terms & conditions (Collection 2).

Video

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6 Questions

Q1.
What are the monomers of proteins?
lipids
fatty acids and glycerol
Correct answer: amino acids
glucose
starch
Q2.
Proteins are used in the body for and repair in the body.
An image in a quiz
Correct Answer: growth, growing
Q3.
What is a catalyst?
a substances that slows down chemical reactions
a substances that stops chemical reactions
Correct answer: a substances that speeds up chemical reactions
Q4.
Scientists use as simpler representations of complex things and ideas.
An image in a quiz
Correct Answer: models, model
Q5.
Where do consumers in food webs get the nitrogen they need to make proteins?
air
water
soil
Correct answer: food
Q6.
True or false? Photosynthesis and respiration involve a series of chemical reactions.
Correct answer: True
False

6 Questions

Q1.
Match each keyword to its meaning.
Correct Answer:Catalyst,substance which speeds up the rate of a reaction without being used up

substance which speeds up the rate of a reaction without being used up

Correct Answer:Substrate,substance which is acted upon by the enzyme

substance which is acted upon by the enzyme

Correct Answer:Enzyme,protein which acts as a biological catalyst

protein which acts as a biological catalyst

Correct Answer:Active site,part of an enzyme where the substrate binds

part of an enzyme where the substrate binds

Q2.
True or false? All enzymes are proteins.
Correct answer: True
False
Q3.
Put the following steps in order to describe how an enzyme works.
1 - The substrate(s) binds to the active site.
2 - An enzyme-substrate complex is formed.
3 - The product(s) is released.
4 - The enzyme can be re-used.
Q4.
What part of the enzyme is A?
An image in a quiz
Correct Answer: Active site, The active site
Q5.
Who is correctly describing the effect of adding an enzyme on the activation energy of an enzyme controlled reaction?
An image in a quiz
Andeep: Enzymes increase the activation energy so the reaction happens faster.
Correct answer: Lucas: Enzymes lower the activation energy so the reaction happnes faster.
Q6.
In the lock and key model of enzyme action, what is the lock?
substrate
Correct answer: enzyme
product(s)