how do biological washing powders work?. objectives know: what an enzyme is and some of the...
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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?