Enzymes

Question 1

What are enzymes?

Answer 1

Enzymes are biological catalysts made of protein

Question 2

what is a catalyst?

Answer 2

A catalyst is a substance that speeds up reactions without
themselves being used up in the reaction

Question 3

What does an enzyme have in the words that make them an enzyme?

Answer 3

Most enzymes have the suffix ‘ase’ at the end.

but there are some that don’t eg pepsin, rennin, and trypsin,

Question 4

Define metabolism

Answer 4

Metabolism is the sun of all chemical reactions in the body of an organism

Question 5

How is the function of a protein decided?

Answer 5

The function of a protein is decided by the sequence
of amino acids but also by the way the protein folds

Question 6

What type of protein are most enzymes?

Answer 6

Globular proteins

Question 7

How do enzymes work?

Answer 7

Enzymes have a specific shape that means that it will fit neatly and react only with a substance whose shape matches the
enzyme.

Question 8

What is a substrate?

Answer 8

Substrate is the substance that an enzyme reacts with.

Question 9

What is a product?

Answer 9

Product is the substance the enzyme forms.

Question 10

What are the two categories of enzyme?

Answer 10

Catabolic and Anabolic enzymes

Question 11

What are catabolic enzymes?

Answer 11

A catabolic enzyme breaks down a substance into smaller
parts.

Amylase (produced in the mouth & pancreas) converts Starch
into Maltose.

Pepsin in the stomach breaks down proteins into peptides

Catalase breaks don hydrogen peroxide in water and oxygen

Question 12

what are anabolic enzymes?

Answer 12

anabolic enzymes use anabolism which is where simple chemicals are changed into
complex chemicals using enzymes & energy.

DNA polymerase forms and repairs DNA. DNA polymerase is anabolic as it converts simpler molecules into more complex molecules.

Question 13

what is formed when the correct enzyme and substrate come together?

Answer 13

When enzymes and their substrates meet and come together they form an Enzyme/Substrate complex

Question 14

what is the induced fit model?

Answer 14

When the substrate enters the active site it causes it to
change shape slightly.
The enzyme then fits more precisely around the substrate
this is known as the Induced Fit model of enzyme action.

Question 15

are enzyme reactions reversible or irreversible?

Answer 15

Enzyme Reactions are reversible

Question 16

What are inhibitors?

Answer 16

Inhibitors attach to enzymes and destroy their shape

When this happens the enzymes are said to be denatured

eg Cyanide denatures an enzyme involved in respiration

Question 17

Give an example of a beneficial enzyme inhibitor

Answer 17

Insecticides affect enzymes in insects causing their death

Drugs can affect enzymes involved in pain causing the pain
to stop

Antibiotics can affect enzymes in bacteria causing the
bacteria to die

Question 18

What factors influence enzyme activity?

Answer 18

Factors that affect enzymes include-

Temperature

pH

Substrate concentration

Enzyme concentration

Question 19

How does temperature affect enzyme activity?

Answer 19

At very low temperatures ice forms, liquids become solids
and enzymes can’t work.

As temperature increases molecules gain kinetic energy which increases the enzymes and the substrates chances of a successful collision. Rate of reaction increases

Question 20

What is the optimum temperature of plant enzymes and animal enzymes?

Answer 20

Human enzymes work best at body temperature (37°C)

Plant Enzymes work best at 20-30 °C

This is the enzymes optimum temperature (the temp it works best at)

Question 21

What is enzyme denaturation?

Answer 21

When the shape is fully lost the enzyme is said to be
denatured this is usually a permanent condition.

Question 22

What causes an enzyme to become denatured?

Answer 22

Enzymes can be denatured by:

-Heating to very high temperatures.
- Very high or low pHs
- Radiation

Question 23

How does increased substrate concentration affect rate of reaction?

Answer 23

If there are a lot of substarte molecules it increases the chnaces of there being a sucessul collisions between the substarte and the enzymes so the rate of reaction increases

Question 24

How does Ph affect rate of reaction for enzymes?

Answer 24

Most enzymes work at ph 6-8. Outisde of this the enzymes become denatured. Their optimum ph is usually 7

Question 25

How does an increased enzyme concentration affect the rate of reaction?

Answer 25

If the amount of enzymes increases then there will be more of a chance of the substrate colliding successfully. Increases the rate of reaction

Question 26

What ph does pepsin work best at?

Answer 26

a ph of 2 in the stomach

Question 27

What are immobilised enzymes?

Answer 27

Immobilised enzymes are enzymes that are attached to each other or to an inert material.

Question 28

What are the methods of Physical immobilisation of enzymes?

Answer 28

Adsorption where enzymes are physically attached to
inactive supports such as glass beads or ceramics

Enclosed by a membrane when enzymes are kept within a
membrane

Trapped in a gel, sodium alginate is commonly used this
allows substrates in and products out

Question 29

Give an example of where immobilised enzymes are used

Answer 29

Bio-processing is the use of enzyme controlled reactions to
produce a product

Bio-processing can be used to produce products such as
cheeses, beer & antibiotics.

Question 30

What are the methods of chemical immobilisation of enzymes?

Answer 30

Bonded to a support: Enzymes chemically bonded to a
support such as glass beads or ceramics
Enclosed within a membrane or gel
Bonded to each other: Enzymes are chemically bonded to
each other

Question 31

What are the ADVANTAGES OF
IMMOBILISED ENZYMES?

Answer 31

Immobilised enzymes can be easily recovered from the
product so you can get a pure sample of product easily

Immobilised enzymes can be reused this cuts costs

Enzymes frequently become more stable when immobilised

Question 32

How does denaturation affect enzyme activity?

Answer 32

If an enzyme is said to denatured the enzyme cannot form enzyme substrate complexes so the enzyme can no longer work and convert substrates into products

Question 33

What are the uses of IMMOBILISED
ENZYMES?

Answer 33

Immobilised Glucose Isomerase converts glucose to
fructose which is used to sweeten drinks

Lactase converts lactose to sweeter sugars glucose and
galactose which are then used by food manufacturers

Penicillin Acylase changes the structure of penicillin to
make more antibiotics that will fight a wider range of bacteria

Question 34

What is solar energy?

Answer 34

Energy from the sun

Question 35

What is cellular energy?

Answer 35

Energy stored in the bonds of biomolecules