IBDP CORE>TOPIC 3.6>ENZYMES
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ASSESSMENT STATEMENT
U-1Enzymes have an active site to which specific substrates bind.
U-2Enzyme catalysis involves molecular motion and the collision of substrates with the active site.
U-3Temperature, pH and substrate concentration affect the rate of activity of enzymes.
U-4Enzymes can be denatured.
U-5 Immobilized enzymes are widely used in industry.
A-1. Methods of production of lactose-free milk and its advantages.
S-1. Design of experiments to test the effect of temperature, pH and substrate concentration on the activity of enzymes.
S-1. Experimental investigation of a factor affecting enzyme activity. (Practical 3)
U-2Enzyme catalysis involves molecular motion and the collision of substrates with the active site.
U-3Temperature, pH and substrate concentration affect the rate of activity of enzymes.
U-4Enzymes can be denatured.
U-5 Immobilized enzymes are widely used in industry.
A-1. Methods of production of lactose-free milk and its advantages.
S-1. Design of experiments to test the effect of temperature, pH and substrate concentration on the activity of enzymes.
S-1. Experimental investigation of a factor affecting enzyme activity. (Practical 3)
PRACTICAL BASED TEACHING: LEARNING BY INVESTIGATING
DAY 1. DEFINE ENZYME AND ACTIVE SITE
Enzymes and catalysts both affect the rate of a reaction. The difference between catalysts and enzymes is that while catalysts are inorganic compounds, enzymes are largely organic in nature and are bio-catalysts. Even though all known enzymes are catalysts, all catalysts are not enzymes.
What are enzymes made up of ? Do enzymes work on any substrate? What is the mechanism by which they work
Enzymes have a specific shape; substrate has a specific or complementary shape to the active site of the enzyme. The active site of enzyme binds only to specific substrates. Active site works as a lock and substrate as a key. This the lock and key model.
However the active site of the enzyme is not rigid and substrate can induce slight changes in shape, this allows substrates of similar structure to bind with same enzyme. This is called induced fit. (topic 7.6.2 HL)
However the active site of the enzyme is not rigid and substrate can induce slight changes in shape, this allows substrates of similar structure to bind with same enzyme. This is called induced fit. (topic 7.6.2 HL)
Effect of temperature, pH and substrate concentration on enzyme activity.
Denaturation of the enzyme
Denaturation is a structural change in a protein that results in the loss (usually permanent) of its biological properties
- Heat and pH are two agents which may cause denaturation of an enzyme
Immobilisation of enzymes and its industrial use
Use of lactase in lactose free milk
Lactose is a disaccharide of glucose and galactose which can be broken down by the enzyme lactase
Historically, mammals exhibit a marked decrease in lactase production after weaning - leading to lactose intolerance (incidence is particularly high in Asian / African / Native American / Aboriginal populations) Lactose-free milk can be produced by purifying lactase (e.g. from yeast or bacteria) and binding it to an inert substance (such as alginate beads) Milk passed over this immobilised enzyme will become lactose-free The generation of lactose-free milk can be used in a number of ways:
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