Enzymes

Question 1

Enzymes def.

Answer 1

Enzymes are biological catalysts made of proteins.

Question 2

All ____________ reactions are controlled by _____________

Answer 2

1. Metabolic
2. Enzymes

Question 3

Structure and features of enzymes

Answer 3

1. Made of protein- enzymes are made of amino acids folded into a 3D shape (globular protein)
2. Produced by ribosomes by amino acids
3. Have a specific shape- enzymes will only work if they have the correct shape. The shape let’s the enzyme attach to the specific molecule they are changing
4. Specific to ph and temperature- enzymes work best in a certain ph and temperature. Anything outside of this can change the shape of the enzyme and will reduce the efficiency of the enzyme in speeding up the reaction.
5. Specific - enzymes are specific to one kind of substrate e.g., lipase won’t act on starch. The enzyme acts like a mould that fits the substrate very closely. Any chemicals that do not fit exactly cannot react with the enzyme.
6. Reactions are reversible- Enzymes can cause a reaction to proceed in either direction meaning they can be anabolic or catabolic

Question 4

Substrate

Answer 4

The substance with which an enzyme reacts

Question 5

Product

Answer 5

The substance the enzyme forms

Question 6

Active site

Answer 6

The part of the enzyme that combines with the substrate and catalyses the reaction to produce the product

Question 7

Induced fit theory

Answer 7

The shape of the active site is complimentary to that of the substrate but they are not identical. The active site of the enzyme is not a fixed shape but is flexible and can change shape slightly to make a better fit to form the enzyme substrate complex

Question 8

Metabolism

Answer 8

The sum of all the chemical reactions that take place within an organism

Question 9

Catabolic reaction

Answer 9

Break down

Question 10

Anabolic

Answer 10

Build

Question 11

Catalyst

Answer 11

A substance that speeds up a reaction without itself being used up in the reaction

Question 12

Catabolic enzyme

Answer 12

Amylase converts starch into maltose

1. Animals: produced in salivary glands and the pancreas in the digestive system
2. Plants: when seeds germinate amylase converts starch into maltose

Question 13

Anabolic enzyme

Answer 13

1. DNA ligase - in genetic engineering to join the two pieces of DNA together
2. DNA polymerase - found in plants and animals that forms and repairs DNA ( it converts simpler molecules into a more complex form

Question 14

Optimum activity

Answer 14

This is when an enzyme is working at its most efficient or maximum rate

Question 15

Denaturation def.

Answer 15

A denatured enzyme is one that has lost its shape and can no longer carry out its function

Question 16

Denaturation explain

Answer 16

When the shape of the active site on the enzyme has changed, the active site can no longer bind to the substrate and therefore the enzyme no longer works

Certain temperatures and ph can denature an enzyme. If an enzyme goes out of its optimum pH or temperature, Then it starts to become denatured and activity is reduced

Question 17

Temperature with enzymes

Answer 17

Above a certain temperature enzyme will begin to lose the 3-D shape, and the reaction rate will slow down. When the shape of an enzyme is fully lost (usually above 50°C) the enzyme is said to be denatured and has lost its ability to function

Question 18

PH with enzymes

Answer 18

Changes in acidity or alkalinity and can alter the shape of the active site of an enzyme as the pH is no longer suitable. If this happens, the active site will no longer fit with the substrate and the enzyme is said to be denatured

Question 19

Bioprocessing

Answer 19

The use of organisms, cells are enzymes to make specific products

Question 20

Bioreactor

Answer 20

A vessel in which cells, organisms or enzymes are placed to manufacture specific products

Question 21

Immobilised enzymes

Answer 21

Enzymes that are attached to an inert material either chemically or physically

Question 22

Methods of immobilising enzymes

Answer 22

1. Attached to insoluble supports
2. Enclosing them within a membrane
3. Tapping them and gel (sodium alginate is commonly used)

Question 23

Advantages of immobilised enzymes

Answer 23

1. The enzymes can be reused which reduces the cost
   2.Produces a clean product
2. Often the process of immobilising an enzyme increases its stability as it is trapped in a gel or membrane

Question 24

Uses of immobilised enzymes

Answer 24

1. Enzyme - glucose
Substrate- fructose
Product - fructose
Use - fructose is sweeter but more expensive than glucose. It is used to sweeten soft drinks.

2. Enzyme- lactase
   Substrate - lactose
   Product - glucose and galactose (sweeter tasting sugars)
   Use - replace condensed milk in the manufacture of toffee and caramel