Enzymes

Question 1

What are enzymes

Answer 1

biological catalysts

They speed up chemical reactions without being used up themselves

Question 2

Why are enzymes so remarkable

Answer 2

They can be specific for really extreme environments

Question 3

How do enzymes structure determine their function

Answer 3

Some enzymes need cofactors
Enzymes shape must be specific in order for it to function

Question 4

What is the active site

Answer 4

A specific area that consists of about 6-10 amino acids.

Question 5

What decides the shape of the active site

Answer 5

The tertiary structure of its amoino acids

Question 6

What are intracellular enzymes

Answer 6

Enzymes that work within the cells of organisms

Question 7

What is a metabolic pathway

Answer 7

a sequence of reactions each catalysed by a different enzyme that results ins. product

Question 8

what are extracellular enzymes

Answer 8

Enzymes that work outside of the cell

eg:amylase and pepsin

Question 9

That is a prosthetic group

Answer 9

A perementantly bound cofactor

Question 10

What is a cofactor

Answer 10

A small non protein molecule that attaches to an enzyme and aids its function

Question 11

What is an example of a prosthetic group

Answer 11

Zinc ions in carbonic anhydrase (found in red blood cells)

Question 12

What is a coenzyme

Answer 12

Small ORGANIC non protein molecules that bind to en enzyme and aid its function

Question 13

What is a common source of co enzymes

Answer 13

Vitamins

Question 14

What is the lock and key hypothesis

Answer 14

The idea that only a certain enzyme and substrate work together
Just like how only one lock works with a key

Question 15

How does the lock and key theory work ( enzyme action )

Answer 15

The substrate molecule fits into the complementary active site,
Temporary hydrogen bonds form between the enzyme and the substrate forming an enzyme substrate complex
The molecules that may have Been joined or split leave the active site, breaking the temp bonds

Question 16

What is the induced fit hypothesis

Answer 16

When the substrate molecule’s fit into the active site, the active site changes shape slightly to mould its self to the substrate. Its like putting on a glove
A glove that’s too small or only has 4 fingers won’t fit but most gloves do

Question 17

How do enzymes speed up reactions

Answer 17

They lower the activation

Question 18

How does heat effect enzyme action

Answer 18

As heat increases, molecules have more Ke and therefore more successful collisions with sufficient energy occur

But after point the enzymes active site denatures and this stops reaction completely

An optimum temperature is just before denaturing occurs

Question 19

What is Q10

Answer 19

rate of reaction at t+10 / rate of reaction at t

Usually 2

Question 20

What is pH

Answer 20

indicates weather a substance is acidic or alkali

Question 21

What is a buffer

Answer 21

a substance that resists change to pH

Question 22

How can pH change enzyme action

Answer 22

pyramid shape, moving the pH away from the optimum reduces reaction rate because the conc of H+ ions affects the tertiary structure of the enzyme molecule

Question 23

How do different enzymes have different optimum temps

Answer 23

Differing amounts of disulphide bridges

Question 24

What is the effect of changing substrate conc on rate of reactions

Answer 24

increases rate until V max is reached (when each enzyme is filled) at this point adding more has no effect

Question 25

What is the effect of changing enzyme conc on rate

Answer 25

increases rate until V max is reached (when each substrate is used) at this point adding more has no effect

Question 26

What is enzyme degradation

Answer 26

When the enzyme molecules are degraded into their amino acids and used to synthesise new ones

Question 27

What is competitive inhibition

Answer 27

Substances whose molecules have similar shapes to substrate and therefore fir into the active site
This stops the enzyme from functioning

Question 28

What happens to the rate of reaction if you increase sub conc with competetive inhibition

Answer 28

Increases rate of reaction as there is higher proportion of substrate compared to inhibitor therefore increasing the probability of a substrate reaching the enzyme

Question 29

What is non competitive inhibition

Answer 29

They are molecules that bind alleosterically and prevent the enzyme from functioning by changing the active site shape

Question 30

What is end product inhibition

Answer 30

When one of the products of the enzyme substrate complex stays tightly bound and stops further action from occurring

Question 31

what is cyanide

Answer 31

KCN is a highly toxic poison as it inhibits aerobic respiration.

Question 32

Green mamba venom

Answer 32

Binds to neuromuscular synapses and causes muscles to stay contracted, leading to suffocation

Question 33

Aspirin

Answer 33

Salycidic acid binds to enzymes that catalyse the formation of prostoglandins. These are cell signalling molecules that are used on pain response.

Question 34

ATPase inhibitors (foxgloves)

Answer 34

Allow more calcium ions to enter muclular cells. This increases the strength of muscle contraction

Question 35

ACE inhibitor

Answer 35

lowers high blood pressure

Question 36

Protease inhibitor

Answer 36

Prevent the reproduction of virus’ within host cells