B4 Enzymes

Question 1

define enzyme

Answer 1

proteins that function as biological catalysts

Question 2

describe how enzyme actions, refer to their shapes (3)

Answer 2

• a substrate is a molecule that changes in the reaction
• an enzyme has a shape that is complementary to the substrate molecules
• when they bond together, substrate change to a product and released

Question 3

properties of enzymes (3)

Answer 3

• proteins
• specific
• no used up in reactions
• work faster in higher temperatures
• can be denatured
• sensitive to pH
• work better in larger surface area

Question 4

describe the effects of temperature on enzyme activity

Answer 4

• high temperature speeds up the movement of substrate molecules, therefore they more frequently collide with enzyme and they have sufficient energy to bond with it, therefore rate of reaction rapidly increases
• the enzyme molecules themselves also gain in energy. as the temperature rises, it begins to vibrate; eventually the enzyme molecules vibrate too much that the active site changes and it denatures, and in that point, the rate of reaction rapidly decreases, therefore substrate can not bind with it.

Question 5

describe the effects of pH on enzyme activity

Answer 5

• when the pH is too high or too low, the bondings are affected. this changes the shape of the active site and denatures the enzyme.