Enzymes

Question 1

What’s a catalyst?

Answer 1

Chemical that speeds up the rate of reaction and remains unchanged and reusable at the end of the reaction

Question 2

What’s extracellular?

Answer 2

Outside the cell

Question 3

What’s intracellular?

Answer 3

Inside the cell

Question 4

What is metabolism

Answer 4

The chemical reactions that take place inside living cells or organisms

Question 5

What’s a product?

Answer 5

Molecule produced from the substrate, by an enzyme catalyses reaction

Question 6

What’s a substrate?

Answer 6

A molecule that is altered by an enzyme catalyses reaction

Question 7

What are enzymes and what do they do?

Answer 7

Biological catalysts that speed up metabolic reactions in living organisms
Catalysts
Number of relations an enzyme catalyses per second is turnover number

Question 8

What metabolic pathways are described as catabolic?

Answer 8

Where metabolites are broken down to smaller molecules and release energy

Question 9

What metabolic pathways are described as anabolic?

Answer 9

Energy is used to synthesise larger molecules from smaller ones

Question 10

What’s an active site?

Answer 10

Indented area on the surface of an enzyme molecule, with a shape that is complementary to the shape of the substrate molecule

Question 11

What’s a cofactors?

Answer 11

A substance that has to be present to ensure an enzyme catalyses reaction takes place at the appropriate rate

Question 12

What’s an enzyme substrate complex?

Answer 12

Complex formed by temporary binding of enzyme and substrate molecules during an enzyme catalyses reaction

Question 13

What’s a prosthetic group?

Answer 13

A cofactors that is permanently bound by covalent bonds to an enzyme molecule

Question 14

Describe carbonic anhydride and its function

Answer 14

Contain a zinc ion prosthetic group permanently bound to its active site
Found in erythrocytes
Catalyses conversion of carbon dioxide and water to carbonic acid which then breaks down into protons and hydrogen carbonate ions

Question 15

How do unbound cofactors work?

Answer 15

Temporarily bind to enzyme or substrate to ease the formation of the complex therefore increasing rate of reaction
Some act as co substrates. The substrate and ion form correct shape to bind to active site
Some change charge distribution on the surface of substrate or active site and make the temporary complex bonds easier to form

Question 16

What are coenzymes?

Answer 16

Small organic non-protein molecules that bind temporarily to the active site of enzyme molecules. They are chemically changed during the reaction and need to be recycled

Question 17

What are enzyme product and enzyme substrate complexes?

Answer 17

An enzyme molecule with the products in its active site. Joined by non covalent force

Same with subtract instead of product

Question 18

What is Q10

Answer 18

Temperature coefficient

Calculated by dividing the t+10 by t

Question 19

Why do enzymes denature at high temperatures?

Answer 19

As temperature increases the enzymes vibrate more. This can break weak bonds in the tertiary structure such as hydrogen and ionic bonds.
This will cause the active site to change shape so the substrate will not fit into it.
This is irreversible
The enzymes are denatured

Question 20

What is a buffer?

Answer 20

Something that resists changes in pH

It can donate or accept hydrogen ions

Question 21

How does pH effect enzymes?

Answer 21

Excess proton interfere with hydrogen bonds and ionic forces so the active site changes shape. It also alters the charges on the active site as they cluster around negatively charged group

Question 22

How does pH affect rate of reaction?

Answer 22

Small changes reduce rate
Hydrogen bonds can reform if optimum pH is reached
Change can also be permanent if extreme pHs

Question 23

What is concentration?

Answer 23

Number of molecules per unit volume

Question 24

What’s an inhibitor?

Answer 24

Substance that stops or reduces a reaction

Question 25

What’s a competitive inhibitor?

Answer 25

Inhibition of enzyme. Similar shape to substrate and competes for active site. Prevents enzyme substrate complex

Question 26

What’s a non competitive enzyme?

Answer 26

Inhibition of enzyme. Attaches to part other than enzymes active site. Changes the shape of active site. Shape no longer complements substrate

Question 27

What can reduce competitive inhibition?

Answer 27

Increase substrate concentration

Question 28

What’s a competitor inhibitor the bonds irreversibly?

Answer 28

Inactivator

Question 29

Where to non competing enzymes bind?

Answer 29

Allosteric site

Question 30

How do non competitive inhibitors work

Answer 30

Distrupts the enzymes tertiary structure and changes it shape
Distortion changes shape of active site

Question 31

How can an enzyme catalyses reaction be regulated?

Answer 31

Negative feedback. Last product is a non competing inhibitor for 1st enzyme in metabolic pathway. This is reversible so can be detached when more product is required

Question 32

What do multi enzyme complexes do?

Answer 32

Increase efficiency of metabolic reactions without increasing substrate concentration
Keep substrates and enzymes in the same vicinity and reduce diffusion time.

Question 33

What’s an inhibitor?

Answer 33

Substance that stops or reduces a reaction

Question 34

What’s a competitive inhibitor?

Answer 34

Inhibition of enzyme. Similar shape to substrate and competes for active site. Prevents enzyme substrate complex

Question 35

What’s a non competitive enzyme?

Answer 35

Inhibition of enzyme. Attaches to part other than enzymes active site. Changes the shape of active site. Shape no longer complements substrate

Question 36

What can reduce competitive inhibition?

Answer 36

Increase substrate concentration

Question 37

What’s a competitor inhibitor the bonds irreversibly?

Answer 37

Inactivator

Question 38

Where to non competing enzymes bind?

Answer 38

Allosteric site

Question 39

How do non competitive inhibitors work

Answer 39

Distrupts the enzymes tertiary structure and changes it shape
Distortion changes shape of active site

Question 40

How can an enzyme catalyses reaction be regulated?

Answer 40

Negative feedback. Last product is a non competing inhibitor for 1st enzyme in metabolic pathway. This is reversible so can be detached when more product is required

Question 41

What do multi enzyme complexes do?

Answer 41

Increase efficiency of metabolic reactions without increasing substrate concentration
Keep substrates and enzymes in the same vicinity and reduce diffusion time.