enzymes

Question 1

whats a catalyst

Answer 1

a substance that speeds up a reaction without changing the substances produced or being changed itself

Question 2

can catalysts be used again

Answer 2

yes

Question 3

what are enzymes

Answer 3

biological catalysts that control the rate of reactions that take place in individual cells and in whole organisms

Question 4

how are enzymes efficient

Answer 4

they dont change the conditions in cytoplasm when speeding up reactions
-remain unaffected and can be used again

Question 5

what type of proteins are enzymes

Answer 5

globular proteins

Question 6

how are enzymes produced

Answer 6

during protein synthesis as the mRNA transcribed from the DNA molecule us translated

Question 7

why are enzymes so specific

Answer 7

as a result of their primary secondary tertiary and quaternary structure

Question 8

specificity

Answer 8

features and functions of enzymes that means as a result of specific shapes each enzyme will only catalyse a specific reaction or group of reactions

Question 9

what bonds hold proteins in enzymes together

Answer 9

intramolecular bonds

Question 10

what effects the efficiacy of the enzymes

Answer 10

change in temp or PH

Question 11

how do temp and PH effect efficacy of enzymes

Answer 11

they affect the intramolecular bonds within the protein that are responsible for the shape of the molecule

Question 12

anabolic reactions

Answer 12

reactions that build new molecules inside cells

Question 13

catabolic reactions

Answer 13

reactions that break down substances inside cells

Question 14

metabolism

Answer 14

sum of anabolic and catabolic reactions in a cell

Question 15

metabolic pathway

Answer 15

series of linked reactions in the metabolism of a cell

Question 16

can enzymes slow down and stop reactions

Answer 16

yes

Question 17

intracellular enzymes

Answer 17

enzymes that catalyse reactions within cells

Question 18

extracellular enzymes

Answer 18

enzymes that catalyse reactions outside of the cell in which they were made

Question 19

three types of names enzymes have

Answer 19

-short name of what enzyme works on or what it does with ase on end
-longer systematic name describing type of reaction being catalysed
-classification number

Question 20

activation energy

Answer 20

energy reacting molecules need to have to break the chemical bonds that hold them together

Question 21

how does raising the temp increase chemical reactions rate

Answer 21

by giving more molecules energy to react

Question 22

why are enzymes needed to increase temp for reactions

Answer 22

normal cells couldnt survive under energy demand and extreme heat needed

Question 23

how do enzymes cataylse reactions

Answer 23

by lowering the activation energy needed for the reaction to take place

Question 24

what do enzymes have to do to lower the activation energy

Answer 24

form a complex with a substrate or substrates of the reaction

Question 25

what happens once an enzyme reacts with a substrate

Answer 25

the products formed are released and the enzyme is free to catalyse more reactions

Question 26

lock and key hypothesis

Answer 26

when active site has for for specific substrate

Question 27

what lowers the activation energy

Answer 27

the formation of the enzyme substrate complex

Question 28

what happens when a complex is formed lock and key

Answer 28

-active site effects bonds in substrate making it easier to break and reacting substances closer so easier to bond. -

Question 29

what happens once reaction complete enzymes lock and key

Answer 29

products no longer fit the active site and complex breaks up releasing products and freeing enzyme for more reactions

Question 30

induced fit hypothesis

Answer 30

active site more flexible and fits around substrate

Question 31

what happens once substrate enters active site induced fit

Answer 31

shape of site molded around substrate to form active complex

Question 32

what happens once reaction complete induced fit

Answer 32

enzyme reverts to inactive relaxed form waiting for another substrate

Question 33

how can you measure the way a factor effects the rate of reaction

Answer 33

the initial rate of reaction each time independent factor changed

Question 34

what must be kept in excess when measuring rate of reaction for enzymes

Answer 34

substrates unless substrate concentration rate is being measured

Question 35

whats the initial rate of reaction

Answer 35

when the reaction proceeds at its fastest rate

Question 36

whats the active site

Answer 36

a small depression in the enzyme caused by the way the enzyme is folded

Question 37

molecular activity

Answer 37

number of substrate molecules transformed by one enzyme per minute

Question 38

what happens when there are to many substrates

Answer 38

the enzymes become saturated and not enough enzymes so rate of reaction effected

Question 39

how does PH effect rate of reaction

Answer 39

PH effects R groups that hold together enzymes bonds

Question 40

how can some enzymes work at high temps

Answer 40

large amount of hydrogen and disulphide bonds

Question 41

enzyme inhibitors

Answer 41

stop enzymes from working

Question 42

reversible inhibitors

Answer 42

dont change enzyme forever

Question 43

2 types of reversible inhibitors

Answer 43

competitive and non competitive

Question 44

shape of competitive inhibitor

Answer 44

same shape as substrate

Question 45

what does competitive do

Answer 45

competes with substrate to form complex

Question 46

what happens if amount of inhibitor fixed

Answer 46

percentage of inhibition decreased by increasing substrate concentration

Question 47

what do non c do

Answer 47

form complex with enzyme or with enzyme substrate complex

Question 48

inhibition of non c

Answer 48

only effected by concentration of inhibitors not substrate

Question 49

how does inhibiton of non c work

Answer 49

change active site shape or complex of substrate and enzyme deform

Question 50

irreversible inhibitors

Answer 50

change enzyme forever

Question 51

inhibition of irreversible inhibitors

Answer 51

inhibitor combines with enzyme by permenant covalent bonding to one of the groups vital for catalysis to occur

Question 52

how do cells control so many reactions

Answer 52

-membrane compartment of reactions apart -variations in PH can change rate of enzymes -

Question 53

regulatory enzymes

Answer 53

have seperate site to active site where molecules can bond to have activating or inhibiting effect

Question 54

end product inhibiton

Answer 54

enzyme at begining of reaction inhibited by product at end

Question 55

describe the structure of starch

Answer 55

alpha glucose glycosidic bonds amylose has 1-4 amylopectin has 1-6 and 1-4 amylose is coiled amylopectin branched compact molecule

Question 56

explain what a catalyst is

Answer 56

speeds up rate of reaction without being changed lowers activation energy provides different pathway

Question 57

whats hydrolysis

Answer 57

breaks glycosidic bonds use of water

Question 58

why bread tastes sweet after chewing for long

Answer 58

maltose disaccharide glucose mono produced to taste sweet

Question 59

why is caffeine not an amino acid

Answer 59

no amine group no carboxyl group no R group

Question 60

why does malonate inhibit enzyme

Answer 60

it has similar structure so can bind into active site and act has competitive inhibitor

Question 61

why increasing temp of enzyme reaction changes rate of reaction

Answer 61

-higher Ek so more substrate enzyme complex formed -high temps denature so less rate -bond changes altering enzyme shape -substrate no longer fits active site

Question 62

why rate of reaction decreases over time

Answer 62

hydrogen peroxide converted into products so less substrate to form complex with enzymes

Question 63

how tropolone effects rate at which grapes turn brown

Answer 63

tropolone similar to substrate acts as competitive inhibitor prevents from binding