Bio C5

Question 1

1. What is a catalyst?

Answer 1

A substance which increases the rate of reaction without being used up or changed itself

Question 2

2. What are enzymes?

Answer 2

Enzymes are biological catalysts that speed up the rate of metabolic reactions

Question 3

3. Describe how enzyme catalyst the reaction

Answer 3

A substrate that fits the specific active site of the enzyme binds to create an enzyme-substrate complex, a reaction occurs (catalysed by the enzyme) and then the products are released

Question 4

4. State 2 factors that affect the rate of an enzyme-controlled reaction

Answer 4

Temperature and pH

Question 5

5. Describe the effect of temperature on the rate of an enzyme-controlled reaction

Answer 5

-As the temperature increases, so does the rate of reaction
- Once the temperature exceeds the optimum, the enzyme denatures and the rate of reaction decreases

Question 6

6. Why does the rate of an enzyme-controlled reaction increase when the temperature increases?

Answer 6

• As the temperature increases the particles have more kinetic energy
• This increases the chance of collisions between molecules being successful and leading to a reaction

Question 7

7. If the temperature increases above the optimum, how does this affect enzyme function?

Answer 7

The active site will be distorted (The shape of active will get changed) as the enzyme denatures and so it will no longer fit the substrate

Question 8

8. Describe the effect of pH on the rate of an enzyme-controlled reaction

Answer 8

-The rate of an enzyme catalysed reaction is fastest at the optimum pH
- If the pH is too high or low, the enzyme will work less efficiently and the active site may be denatured at extremes of pH

Question 9

9. How does a pH that is very different from the optimum affect enzyme activity?

Answer 9

The change in pH will distort the enzyme’s active site (denaturing it) so that it can no longer fit the specific substrate