enzymes

Question 1

what is the role of enzymes

Answer 1

to speed up metabolic reactions in living organisms

Question 2

why can enzyme be reused?

Answer 2

they remain unchanged

Question 3

give 3 benefits of enzymes compared to chemical catalysts

Answer 3

they can be re-used
they work well in body conditions
they are specific for certain reaction

Question 4

what is an anabolic reaction

Answer 4

breaking 1 substrate into 2 products

Question 5

what is a catabolic reaction

Answer 5

2 substrates need to break to result in one product

Question 6

describe how an anobolic reaction occurs

Answer 6

the enzyme holds 2 molecules close together at the active site and the bonds then join them together

Question 7

describe how a catabolic reaction occurs

Answer 7

the active site holds the substrate in the correct position to put a strain on certain bonds, the bonds break gibing 2 products

Question 8

what are intracellular enzymes

Answer 8

act inside a cell

Question 9

what is the enzyme called which breaks down hydrogen peroxide

Answer 9

catalase

Question 10

what is the equation for the break down of hydrogen peroxide

Answer 10

2H2O2–> 2H2O+O2

Question 11

what is the turnover of the enzyme catalase

Answer 11

6 million per second

Question 12

what is a metabolic pathway

Answer 12

a series of enzymes that result in the final product

Question 13

what is an extracellular enzyme

Answer 13

enzymes that are secreted out of the cell

Question 14

give an example of an extracellular enzyme

Answer 14

digestive enzyme

Question 15

what does amylase break down

Answer 15

starch

Question 16

what does pepsin break down

Answer 16

proteins

Question 17

what does lipase break down

Answer 17

lipids

Question 18

what is fungi made up of

Answer 18

hyphae threads

Question 19

what are 2 models for enzyme action called

Answer 19

lock and key model
induced fit

Question 20

describe the lock and key model

Answer 20

the substrate is a complimentary shape to the active site of the enzyme (rigid shape) and fits in perfectly, chemically compatiable

Question 21

describe the induced fit model

Answer 21

enzyme and substrate don’t fit perfectly, as the substrate fits into the active site there is a slight change in the shape of the active site (moulds around), they had to be chemically compatiable with eachother

Question 22

why do cells only need a very small concentration of each different enxyme

Answer 22

can be re-used again and again

Question 23

what does the Q10 value mean

Answer 23

the rate of reaction doubles for every 10 degree temperature rise

Question 24

what is the equation for the Q10 value

Answer 24

ROR (T+10 degree)/ ROR at T degree

Question 25

how does the structure of enzymes that are in extreme environments adapt

Answer 25

lots of disulfide bonds so as the temperature rises it does not change shape or denature

Question 26

draw the graph of change in pH

Question 27

what changes if the pH changes

Answer 27

the balance of ions change

Question 28

what bond does a change in pH affect

Answer 28

ionic bonds

Question 29

what is the ion for acids

Answer 29

H+

Question 30

what is the ion for alkalines

Answer 30

OH-

Question 31

what pH do most enzymes work best at

Answer 31

7

Question 32

what is used to fix the pH of a solution

Answer 32

buffer solution

Question 33

describe what happens when the substrate concentration increases

Answer 33

the ROR increases to a certain point, any further addition of the substrate does not increase the ROR

Question 34

describe how an enzyme catalyses a reaction

Answer 34

enzyme + substrate creates an ESC forms an EPC enzyme + product

Question 35

describe what happens when the enzyme concentration increases

Answer 35

with more enzymes present, more substrates will bind to an empty active site on an enzyme, once there are no more substrates left the ROR has not continue

Question 36

explain why an increase in temperature increases the rate of enzyme activity

Answer 36

the enzyme and substrate will have more kinetic energy and collide more, so there is more ESC meaning more product is released

Question 37

what is an enzyme inhibitor

Answer 37

molecules that prevent enzymes from carrying out their normal function of catalysis

Question 38

what is a competitive inhibitor

Answer 38

a molecule that fits in the active site blocking the substrate and stops the catalytic reaction

Question 39

give an example of a competitive inhibitor

Answer 39

statins to reduce blood cholesterol concentration

Question 40

what is a non-competitive inhibitor

Answer 40

binds to the enzyme other than the active site (allosteric site)

Question 41

does substrate concentration affect the inhibitor in competitive inhibitors

Answer 41

yes the substrate added, teh greater chance it will out compete the inhibitor for the active site and the more ROR will increase

Question 42

will increasing the substrate concentration make any difference to the ROR in a non-competitive inhibitor

Answer 42

no as the enzyme has permantly changed shape

Question 43

give an example of a non-competitive inhibitor

Answer 43

PPI's (block enzyme activity which releases stomach acid to stop stomach ulsers)

Question 44

give 2 characteristics of a non-competitive inhibitor

Answer 44

irreversible highly toxic

Question 45

give an example of an inhibitor which can be a metabolic poison and explain it

Answer 45

cyanide attach to the enzyme involved in cellular respiration and causes the organism to die

Question 46

what is an 'end-product inhibition'

Answer 46

when a product of a reaction can inhibit one of the enzymes involved in its own production

Question 47

why are 'end product inhibition' useful (2 ways)

Answer 47

regulates the metabolic pathway (don't make too much product) avoids wasting cell resources

Question 48

what are enzymes called when they are made in inactive forms

Answer 48

pre-cursors

Question 49

what is the reason for pre-cursors

Answer 49

to prevent damage of our cells

Question 50

what needs to happen for pre-cursors to be activated

Answer 50

they need to undergo a change in shape of their active site with the help of co-enzymes and co-factors

Question 51

what helps change the change shape of the pre-cursors active site

Answer 51

adding a co-factor or co-enzyme

Question 52

what is a apoenzyme

Answer 52

a pre-cursor (inactive)

Question 53

what is a holoenzyme

Answer 53

an active pre-cursor

Question 54

give 2 characteristics of a co-factor

Answer 54

inorganic not used up in a reaction

Question 55

give an example of a co-factor

Answer 55

chloride ions needed to activate salivary amylase which digests starch

Question 56

what are co-enzyme and co-factors

Answer 56

increase enzyme activity

Question 57

give 2 characteristics of co-enzymes

Answer 57

organic altered by the reaction

Question 58

give an example of a co-enzyme

Answer 58

vitamins

Question 59

what is a prosthetic group

Answer 59

they are co-factors or co-enzymes that are tightly attached to an enzyme and may be permanently attached

Question 60

What do co-factors do to promote enzyme activity

Answer 60

Helping the enzyme and substrate join

Question 61

How do co-enzymes increase enzyme activity

Answer 61

They act as carriers moving chemical groups between different enzymes in metabolic pathways