proteins and enzymes

Question 1

function of haemoglobin

Answer 1

allows oxygen to bind and be transported around the organism

Question 2

function of antibody

Answer 2

binds to specific antigens
used in an organisms immume system response to a pathogen

Question 3

function of enzymes

Answer 3

lowers Ea within a metabolic reaction

Question 4

function of actin and myosin

Answer 4

involved in muscle contraction

Question 5

function of keratin

Answer 5

found in nails for strength

Question 6

how many types of amino acids

Answer 6

20

Question 7

strcutre of an amino acid

Answer 7

Question 8

bond between amino acids

Answer 8

peptide

Question 9

primary structre

Answer 9

order and sequence of amino acids in a polypeptide chains

Question 10

secondary structure

Answer 10

the way the polypeptide chain chain folds into
alpha helixes or beta pleated sheets
held together by weak H bonds

Question 11

tertiary structure

Answer 11

further folding into specific 3D complex shape
r groups determine how it folds - ionic/weak H/disulphide bonds

Question 12

what does the tertiary stucture determine

Answer 12

the shape of the protein is specific to its function and it determines how it interacts with other molecules

Question 13

quaternary strcuture

Answer 13

consists of 2 or more polypeptide chains
globular or structural protein

Question 14

denaturation of proteins

Answer 14

increasing temp increases kinetic energy of molecules, making them vibrate more
this can break weak H bonds in 2/3 strcuture
changing the pH breaks ionic bonds
this changes 3 strucutre

Question 15

biuret test for proteins

Answer 15

2cm3 of biurets reagent with 2cm2 of sample
colour change is purple

Question 16

what kind of protein is an enzyme

Answer 16

globular

Question 17

how are products formed

Answer 17

when bonds are broken and reformed

Question 18

initial bond breaking requires

Answer 18

activation energy

Question 19

how do enzymes increase the rate of reaction

Answer 19

lower Ea for a chemical reaction

Question 20

how do enzymes lower the Ea

Answer 20

stressing bonds in the substrate during the formation of an enzyme substrate complex which allows reactions to occur at lower temps

Question 21

enzyme structure

Answer 21

active site
specific tertiary structure
specific complimentary shape to substrate

Question 22

lock and key model

Answer 22

active site is rigid and doesnt change
the substrate binds to the enzymes active site
substrate fits exactly to the active site (complimentary)
enzyme substrate complex reached, product formed and no longer fit into the active site so it released
enzyme is free to partake in another reaction

Question 23

induced fit model

Answer 23

substrate enters the enzymes active site and binds to it formin ESC
the binding of the subrate induces the change in the shape of the active site
the slight change in shape of the specific 3d tertiary stucture of the active site distorts the bonds within the substrate to lowers Ea of reaction
when substrate leaves, the active site returns to the original shape

Question 24

difference in induced fit model

Answer 24

active site isnt rigid
when substrate binds, the active site becomes more complimentary

Question 25

enzyme conc as a factor affecting enzyme action

Answer 25

inititially ROR increases because the ESC being formed per sec increases eventually the graph plateus as the substrate becomes the limiting factor

Question 26

substrate conc as a factor affecting enzyme action

Answer 26

inititially ROR increases because the ESC being formed per sec increases eventually the graph plateus as the enzyme becomes the limiting factor all the enzyme active sites fully occupied maximum number of ESC formed per sec

Question 27

pH as a factor affecting enzyme action

Answer 27

as pH moves away from the optimum the ionic bonds in the tertiary structure are altered altering the shape of the active site active site is no longer complimentary to the substrate less/no ESC can form

Question 28

temperature as a factor affecting enzyme action

Answer 28

as temp increases the kinetic energy increases more successful collisions, more ESC form increases the ROR at optimum temp the maximum number of ESC are formed per sec past the optimum the weak H bonds break changing the tertiary structure of the enzyme making the active site no longer complimentary to the substrate less/no ESC can form

Question 29

conc of competitive inhibitor as a factor affecting enzyme action

Answer 29

at both high and low concentrations, the rate will eventually reach the same as without an inhibitor as enough substrate is added low conc will require less substrate added to overcome the inhibition and reach the maximum rate of reaction high conc will require more substrate added to overcome the inhibition and reach the maximum rate of reaction

Question 30

conc of non competitive inhibitoras a factor affecting enzyme action

Answer 30

the maximum rate of reaction will never reach the same maximum rate of reaction as it would with no inhibitor present the maximum rate will be lower at a higher concentration of non competitive inhibitor

Question 31

what are inhibitors

Answer 31

substances which decrease the ROR

Question 32

competitive inhibitors

Answer 32

have a similar structure to substrates they bind to the active site temporarily prevent the substrate from bidning some product formed but takes longer than without the inhibitor can be overcome by increasing substrate concentration

Question 33

non competitive inhibitors

Answer 33

binds to allosteric site causes a change to the shape of enzyme so substrates cannot bind

Question 34

Describe the induced fit model of enzymic action

Answer 34

1. (before reaction) active site not complementary to substrate; 2. Shape of active site changes as substrate binds/as enzyme-substrate complex forms; 3. Stressing/distorting bonds (in substrate leading to reaction);