How do biological washing powders work?

What are enzymes?Objectives

Know: What an enzyme is and some of the functions

they carry out.

Understand: Why enzymes have the structure which

they do.

Outcomes3: Describe how long chains of amino acids are folded and coiled into special shapes to form enzymes.

5: Relate the structure of an enzyme to its function.

7: Explain the concepts of activation energy and the active site of the enzyme.

Key terms: enzyme, active site, lock and key, substrate, complex

What are enzymes?Every cell requires hundreds of biochemical reactions to survive and carry out its function.

Nearly all of these are catalyzed large globular proteins called enzymes.

Enzymes can speed up reactions by a factor of many millions, but they cannot catalyze reactions that would otherwise not occur.

Enzymes catalyze both anabolic (building up) and catabolic (breaking down) reactions.

Structure of enzymesAll enzymes are globular proteins. They are soluble in water due to the presence of many hydrophilic side groups on their constituent amino acids.

Most enzymes are very large molecules but only a small part of them is involved in catalysis. This is called the active site and it may consist of just a few amino acids.

The remainder of the amino acids maintain the precise shape of the enzyme and the active site.

active site

What happens at the active site?In the same way that a key fits into a lock, so a substrate is thought to fit into an enzyme’s active site. The enzyme is the lock, and the reactant is the key.

enzyme

reactant

+enzyme-reactant

complex↔products

enzyme

+↔

+ ↔ ↔ +

Key terms: enzyme, active site, lock and key, substrate

Outcomes3: Describe how long chains of

amino acids are folded and coiled

into special shapes to form

enzymes.

5: Relate the structure of an enzyme to its

function.

7: Explain the concepts of

activation energy and the active

site of the enzyme.

What are enzymes?

Outcomes3: Describe how long chains of

amino acids are folded and coiled

into special shapes to form

enzymes.

5: Relate the structure of an enzyme to its

function.

7: Explain the concepts of

activation energy and the active

site of the enzyme.

Key terms: enzyme, active site, lock and key, substrate, complex

Induced fit

What are enzymes?

Key terms: enzyme, active site, lock and key, substrate

Outcomes3: Describe how long chains of

amino acids are folded and coiled

into special shapes to form

enzymes.

5: Relate the structure of an enzyme to its

function.

7: Explain the concepts of

activation energy and the active

site of the enzyme.

Draw diagrams with text to explain around them explaining the difference between the lock and key and induced fit models of enzyme action.

What are enzymes?

Why do enzymes increase the rate?

Enzymes lower the activation energy of a reaction

Progress of reaction (time)

Ener

gy le

vels

of m

olec

ules

Enzymes lower the activation energy of a reaction

Final energy state of products

Initial energy stateof substrates

Activation energyof uncatalysed reactionsActivation energy

of enzyme catalysedreaction

Progress of reaction (time)

Ener

gy le

vels

of m

olec

ules

Identifying enzyme terms

Outcomes3: Describe how long chains of

amino acids are folded and coiled

into special shapes to form

enzymes.

5: Relate the structure of an enzyme to its

function.

7: Explain the concepts of

activation energy and the active

site of the enzyme.

Key terms: enzyme, active site, lock and key, substrate, complex

Questions

1. What is an amino acid?

2. Enzymes are what type of molecules?

3. How would you describe the function of an enzyme?

4. Different enzymes have different?

5. Why are enzymes different shapes?

6. The area a substrate binds to on an enzyme is the?

7. When it does what is formed?

8. When we talk about enzymes and substrates fitting together which model do we use?

9. Why do enzymes speed up reactions?

What are enzymes?