Topic 5 / Enzymes

Question 1

Define catalyst

Answer 1

Substance that increases rate of a chemical reaction and is not changed by the reaction

Question 2

Define enzyme

Answer 2

Proteins that function as biological catalysts.

Question 3

Why enzymes are important in all living beings in terms of reaction speed necessary to sustain life

Answer 3

Enzymes lower the activation energy needed for a reaction. Instead, they provide an alternate way that has lower activation energy, meaning that the reactent molecules will have more energy to bypass the energy barrier and so more reactants are turned into products.

Question 4

Specificity of enzymes

Answer 4

An enzyme that normally acts on one substance will not act on a different one. the shape of the active site is complementary to the specific substrate and enzyme.

Question 5

Effects of pH

Answer 5

different pH levels may denature enzymes permanently. The active site becomes deformed: as a result, the enzyme and substrate no longer are complementary and can’t fit together.

Question 6

Effects of temperature

Answer 6

As temperatures increase, the molecules gain kinetic energy, moving faster with greater chance of collisions: rate of reaction increases. At a higher temperature, the enzymes become irreversibly denatured and the active site becomes deformed and the enzyme changes shape.

Question 7

Enzyme action

Answer 7

Enzymes and substrates have complementary shapes. They fit together and the enzymes speeds up the reaction immensely.