5. Enzymes

Question 1

What is the optimum pH for an enzyme?

Answer 1

The pH at which the enzyme works the best.

Question 2

What is denaturation of an enzyme?

Answer 2

A permanent alteration in the enzyme’s active site.

Question 3

What are factors that can lead to denaturation of an enzyme?

Answer 3

pH and temperature.

Question 4

What is the function of the enzyme amylase?

Answer 4

It breaks down starches into sugars (like glucose).

Question 5

What is the function of the enzyme lipase?

Answer 5

It breaks down fat in the stomach.

Question 6

What is the function of the enzyme maltase?

Answer 6

It breaks down maltose (sugar) into glucose.

Question 7

What is the function of the enzyme trypsin?

Answer 7

It breaks down proteins into amino acids.

Question 8

What is the function of the enzyme lactase?

Answer 8

It breaks down lactose into glucose and galactose.

Question 9

What is a catalyst?

Answer 9

a substance that increases the rate of a chemical reaction but is unchanged by the reaction

Question 10

What are enzymes?

Answer 10

proteins involved in all metabolic reactions, functioning as biological catalysts

Question 11

Why are enzymes important?

Answer 11

provide reaction rate necessary to sustain life

Question 12

What are some uses of enzymes? (do not need to name all)

Answer 12

• food production
• agriculture
• cosmetic and pharmaceutical industries
• production of biofuels.
• production of cheese, bread, leather, fruit juice and lactose-free milk
• production of certain textiles
• medical diagnostic testing
• digestion, breaking down substances in food

Question 13

Describe enzyme action.

Answer 13

• each type of enzyme has a specific shape that fits the reactants in the reaction
• shape of active site and substrate are complementary
• substrate fits into active site and reaction happens
• product(s) leave the active site.
• enzyme is ready to act again

Question 14

Investigate and describe the effect of changes in temperature on enzyme activity.

Answer 14

• low temp: KE of molecules too low for effective collisions to occur, breakdown rate low
• as temp increases, so does KE of the molecules, causing more effective collisions
• temp exceeds optimum temperature of the enzyme, active site shape changes (no longer fits) enzyme begins to denature, slowing the reaction

Question 15

Investigate and describe the effect of changes in pH on enzyme activity.

Answer 15

• optimum pH at which the shape of the active site allows the enzyme to work most efficiently
• above and below optimum pH, enzyme undergoes denaturation

Question 16

What is an enzyme-substrate complex?

Answer 16

structure formed when a substrate attaches to the active site of an enzyme

Question 17

structure formed when a substrate attaches to the active site of an enzyme

Answer 17

enzyme-substrate complex

Question 18

What is the active site?

Answer 18

region of an enzyme where catalysis happens and fits with substrate

Question 19

What is the substrate?

Answer 19

reactant in an enzyme-catalysed reaction

Question 20

Explain the specificity of enzymes.

Answer 20

• each type of enzyme only works for one/very few reactions
• active site has a specific shape that only the correct substrate (or a very similarly shaped molecule) can fit into (complementary)

Question 21

It breaks down starches into sugars (like glucose).

Answer 21

amylase

Question 22

It breaks down fat in the stomach.

Answer 22

lipase

Question 23

It breaks down maltose (sugar) into glucose.

Answer 23

maltase

Question 24

It breaks down proteins into amino acids.

Answer 24

trypsin

Question 25

It breaks down lactose into glucose and galactose.

Answer 25

lactase

Question 26

Explain enzyme action in more detail.

Answer 26

• enzyme’s active site and substrate fit together to make an enzyme–substrate complex
• reaction happens
• products are produced and detach from enzyme, making it available to catalyse another reaction