Chapter 4~ Enzymes

Question 1

what are enzymes

Answer 1

biological catalysts which speed up the rate of reaction without being used up itself by lowering the activation energy or by providing an alternative pathway

Question 2

intracellular enzymes are
example

Answer 2

enzymes which act within cells
Catalase which ensures the breakdown of hydrogen peroxide into oxygen and water

Question 3

extracellular enzymes are
example

Answer 3

work outside of cells which make them
amylayse and trypsin which are involved in digestion

Question 4

what are the mechanisims of enzyme actions

Answer 4

1. lock and key model
2. the induced fit model

Question 5

the lock and key model

Answer 5

the substrate fits into the enzymes active site the same way in which a key fits into a lock. the substrate shape and active site is perfectly complementary to eachother

Question 6

lock and key model process1

Answer 6

1, substrate binds to active site forming an ENZYME SUBSTRATE COMPLEX
2. enzyme converts substrate into a product forming an ENZYME PRODUCT COMPLEX
3. product is released from enzymes active site

Question 7

induced fit model

Answer 7

it suggests that the shape of the enzymes active site and substrate is not exactly complementary but when the substrate enters active site a conformational change occurs which induces catalysis

Question 8

process of induced fit model1

Answer 8

1. substrate enters enzymes active site forming an enzyme substrate complex
2. enzyme undergoes a conformational Change causing substrate to change into product forming an ENZYME PRODUCT COMPLEX.
3. product released into enzymes active site.

Question 9

what are the factors affecting the rate of reaction

Answer 9

enzyme concentration, substrate concentration, temperature and PH

Question 10

TEMPERATURE

Answer 10

as temperature increases, kinetic energy increases so particles move faster and colide this results in more sucessful frequent collisions allowing more ES complexes to form. however the enzyme becomes dentaured after optimum temperature as too much kinetic energy breaks the bonds between the amino acid r groups and so the shape of the active side changes and can no longer be complementary to the substrate decreasing the rate of reaction.

Question 11

what is optimum temperature

Answer 11

the temperature at which the rate of activity pf enzymes is at its highest

Question 12

what is the temperature coefficient

Answer 12

q10 it tells you how much a reaction rate changes when temperatures is raised by 10 degrees.

Question 13

PH

Answer 13

Enzyme denatures above and below optimum PH.

Question 14

enzyme concentration

Answer 14

enzyme conc increases, rate of reaction increases more active sites are availiable to bind to substrate this means more frequent collisions between enzyme and substrate so more ES COMPLEXES can form.

Question 15

substrate concentration

Answer 15

substrate concentration increases, rate of reaction increases, more substrate molecules to fill enzymes active sites. more frequent collisions so more ES COMPLEXES

Question 16

saturation point

Answer 16

all of the enzymes active sites are occupied with substrate molecules

Question 17

V max

Answer 17

maximum point of reaction.
all active sites are occupied by substrate particles so no more ES complexes can form

Question 18

cofactors

Answer 18

non protein molecules which need to be bound to an enzyme for it to work
it is also called a prosthetic group if bound tightly to enzyme with bonds.
inorganic
chemically unchanged

Question 19

coenzymes

Answer 19

organic molecules
chemically altered
they allow an enzyme to function and transfer chemical groups between enzymes

Question 20

enzymes are activated by ——
and inactivated by ——-

Answer 20

co factors
inhibitors

Question 21

competitive inhibitors

Answer 21

do not change v max
bind to active site of enzyme and block the substrate binding.

Question 22

non competitive inhibitor

Answer 22

bind to the site of an enzyme away from its active site known as the allosteric site.

Question 23

inactive percursor form

Answer 23

enzymes which can cause damage within cells producing them or to tissues where they are released or enzymes whose actions need to be controlled.
need to undergo change in shape to be activated done by adding a cofactor.

Question 24

end product inhibition

Answer 24

final product in a metabolic pathway which inhibits an enzyme that has acted earlier on in the pathway. it regulates metabolic pathways and controls amount of product produced.

Question 25

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