B5.1 Enzymes

Question 1

What is enzyme

Answer 1

proteins involved in all metabolic reactions, where they function as biological catalysts.

They have a particular shape (only work/bind on 1 type of substrate)
Inside cells
It doesn’t get used up

Question 2

How do enzymes work as biological catalysts

Answer 2

1. put small molecules together to make bigger molecules (e.g. amino acid –> protein)
2. break up larger molecules to form smaller ones
   (e.g. starch –> glucose)

Question 3

What is active site

Answer 3

special region in enzyme where chemical reaction takes place. It has a specific shape fitting with other molecules

Question 4

What is a catalyst

Answer 4

A substance that speeds up a reaction without being used up

Question 5

What is substrate

Answer 5

Molecules that fit into an enzyme. substance acted on by enzyme. The substrate molecules become product molecules

Question 6

How are the shapes of active site and substrate

Answer 6

complimentary

Question 7

How do enzymes work (break down of large molecules)

Answer 7

1. Big substrate molecule fits into the active site
2. An enzyme substrate complex is formed and bond in substrate weakens and breaks
3. 2 smaller products are made, then enzyme goes on to break down another substrate

Question 8

How do enzymes work (production of bigger molecules)

Answer 8

1. substrate molecules fit side by side into the active site
2. Enzyme substrate complex is formed and this brings substrate molecules together so they can form a bond
3. This makes a bigger molecule and enzyme is used again for another set

Question 9

What is the lock and what is the key
What is the screwdriver what is the screw

Answer 9

Lock/screwdriver = Enzyme
Key/screw = Substrate

Question 10

Catalase

Answer 10

enzyme that breaks down hydrogen peroxide
2H2O2 —–catalase—-> 2H20 + o2

Question 11

effect of temperature on enzyme

Answer 11

As temperature increases = Rate of reaction increases as:
molecules have more EK = move rapidly = more effective collisions = more enzyme substrate complex = more product

As the temperature increases too much = enzyme denatures and active site changes shape (permanently)
They lost ability to catalyze the reaction
Rate of reaction decreases as substrates cant bind

Question 12

for enzyme to work it must

Answer 12

1. come in physical contact with substrate
2. have an active site fitting the substrate

Question 13

Optimum temperatue

Answer 13

When rate of reaction is highest (human = 37)

Question 14

Effect of pH on enzymes

Answer 14

Enzyme works best in different pH’s (different optimum)
Increase in pH above/below optimum = affect rate of reaction
If change is extreme enxyme denatures:
affects interaction between AA in chain and can make enzymes unflod –> change shape of AS = enzyme denatures

Question 15

optimum pH for enzymes EX

Answer 15

pepsin = 2
trypsin = 8
pH 2= in stomach
pH 7 = neutral and found in mouth
pH 9 - alkaline and found in SI

Question 16

What words shows that something is an enzyme

Answer 16

-ase