understanding
- Enzymes have an active site to which specific substrates blind
- Enzyme catalysis involves molecula motion and the collision of substrates with the active site
- Temperature, pH and substrates concentration affect the rate of activity of enzymes
- Enzymes can be denatured
- Immobilzed enzymes are widely used in industry
nature of science
- Experimental design: accurate quantitive measurements in enzyme experiments require replicates to ensure reliability
applications
- Methods of production of lactose-free milk and its advantages
skills
- Design of experiments to test the effect of temperature, pH and substrate concentration on the activity of enzymes
- Experimental investigation of a factor affecting enzyme activity
what are enzymes?
induced fit model
•When the substrate approaches the enzyme, there is a conformational change in the active site
•Alters stability of bonds in the substrate
•Alters stability of bonds in the substrate
Factors affecting catalatyc activity of enzymes
Temperature
- As the temperature rises, reacting molecules have more and more kinetic energy. This increases the chances of a successful collision and so the rate increases. There is a certain temperature at which an enzyme's catalytic activity is at its greatest. This optimal temperature is usually around human body temperature (37.5 oC) for the enzymes in human cells.Above this temperature the enzyme structure begins to break down (denature) since at higher temperatures intra- and intermolecular bonds are broken as the enzyme molecules gain even more kinetic energy.
- As the temperature rises, reacting molecules have more and more kinetic energy. This increases the chances of a successful collision and so the rate increases. There is a certain temperature at which an enzyme's catalytic activity is at its greatest. This optimal temperature is usually around human body temperature (37.5 oC) for the enzymes in human cells.Above this temperature the enzyme structure begins to break down (denature) since at higher temperatures intra- and intermolecular bonds are broken as the enzyme molecules gain even more kinetic energy.
pH
- Each enzyme works within quite a small pH range. There is a pH at which its activity is greatest (the optimal pH). This is because changes in pH can make and break intra- and intermolecular bonds, changing the shape of the enzyme and, therefore, its effectiveness.
- Each enzyme works within quite a small pH range. There is a pH at which its activity is greatest (the optimal pH). This is because changes in pH can make and break intra- and intermolecular bonds, changing the shape of the enzyme and, therefore, its effectiveness.
Concentration of enzyme and substrate
- The rate of an enzyme-catalysed reaction depends on the concentrations of enzyme and substrate. As the concentration of either is increased the rate of reaction increases.
For a given enzyme concentration, the rate of reaction increases with increasing substrate concentration up to a point, above which any further increase in substrate concentration produces no significant change in reaction rate. This is because the active sites of the enzyme molecules at any given moment are virtually saturated with substrate. The enzyme/substrate complex has to dissociate before the active sites are free to accommodate more substrate.
Provided that the substrate concentration is high and that temperature and pH are kept constant, the rate of reaction is proportional to the enzyme concentration.
- The rate of an enzyme-catalysed reaction depends on the concentrations of enzyme and substrate. As the concentration of either is increased the rate of reaction increases.
For a given enzyme concentration, the rate of reaction increases with increasing substrate concentration up to a point, above which any further increase in substrate concentration produces no significant change in reaction rate. This is because the active sites of the enzyme molecules at any given moment are virtually saturated with substrate. The enzyme/substrate complex has to dissociate before the active sites are free to accommodate more substrate.
Provided that the substrate concentration is high and that temperature and pH are kept constant, the rate of reaction is proportional to the enzyme concentration.
Sources
Pearson Textbook
Biology Study Guide
Molecular Biology Notes
Pearson Textbook
Biology Study Guide
Molecular Biology Notes
tok questions
Should knowledge be shared when techniques developed in one part of the world are more applicable in another?
yes i think that knowledge should be shared when techniques developed in one part of the world are more applicable in another.
yes i think that knowledge should be shared when techniques developed in one part of the world are more applicable in another.