Enzymes are biological catalysts that speed up chemical reactions in living organisms. They work by specifically binding to substrate molecules through complementary shapes. This binding forms an enzyme-substrate complex that lowers the activation energy to produce products. Enzyme activity is affected by temperature and pH levels as changes can alter the enzyme's shape and ability to bind substrates properly or cause denaturation.

1. ENZYMES

3. LEARNING OBJECTIVE:
• Define the term catalyst.
• Define enzymes.
• Describe why enzymes are important in all living organisms in terms of reaction
speed necessary to sustain life.
• Describe enzyme action with reference to the complementary shape of an
enzyme and its substrate and the formation of a product.
• Explain enzyme action with reference to the active site, enzyme-substrate
complex, substrate and product.
• Explain the specificity of enzymes in terms of the complementary shape and fit of
the active site with the substrate.
• Explain the effect of changes in temperature on enzyme activity in terms of
kinetic energy, shape and fit, frequency of effective collisions and denaturation.
• Explain the effect of changes in pH on enzyme activity in terms of shape and fit
and denaturation.

4. VOCABULARY
• CATALYST
• ENZYME
• SUBSTRATE
• PRODUCT
• ACTIVE SITE
• COMPLEMENTARY SHAPE OF ENZYME AND SUBSTRATE
• ENZYME-SUBSTRATE COMPLEX
• SPECIFICITY
• ANABOLIC REACTION
• CATABOLIC REACTION
• INTRACELLULAR ENZYME
• EXTRACELLULAR ENZYME
• OPTIMUM TEMPERATURE
• OPTIMUM pH
• PEPSIN
• PANCREATIC LIPASE
• AMYLASE

6. SPECIFICITY

8. LOCK AND KEY MODEL

9. ANABOLIC REACTION

13. CATABOLIC REACTION

16. RATE OF REACTION

17. • OPTIMUM TEMPERATURE
• OPTIMUM pH
• DENATURATION

18. FACTORS AFFECTING RATE OF REACTION

19. FACTORS AFFECTING RATE OF REACTION

20. Effect of concentration of substrate and
enzyme on rate of reaction

21. GRAPHICAL RESENTATION