Enzymes

Question 1

Definition of an enzyme

Answer 1

Globular protein with a specific tertiary structure which acts as a biological catalyst and increases the reaction rate by lowering the activation energy

Question 2

what is a catalyst?

Answer 2

speeds up reactions remains unchanged at the end

Question 3

what happens to almost all reactions in living organisms?

Answer 3

they are catalysed by enzymes

Question 4

a purpose of anabolic reaction?

Answer 4

to build complex molecules from simple ones

Question 5

what is an intra cellular enzyme?

Answer 5

enzyme that act inside cells e.g. hydrolases in lysosomes

Question 6

what is an extra cellular enzyme?

Answer 6

enzyme that acts outside of a cell e.g. digestive enzyme

Question 7

how are enzymes named?

Answer 7

end in ase sometimes sin - derived from the substrate

Question 8

what does lactase catalyse?

Answer 8

the break down of lactose into glucose and galactose

Question 9

what enzyme catalyses creating glycogen?

Answer 9

Glycogensynthetase

Question 10

what are globular proteins made of?

Answer 10

amino acids

Question 11

what is the structure of a globular protein?

Answer 11

3D

Question 12

what is a globular protein soluble in?

Answer 12

water

Question 13

how does a globular protein hold its 3D structure?

Answer 13

hydrophilic r groups on the outside and hydrophobic r groups on the inside

Question 14

what is an active site?

Answer 14

depression on the surface of an enzyme to which a specific substrate binds

Question 15

what is unique about the active site?

Answer 15

it is complementary

Question 16

in Lock and Key how does the substrate bond?

Answer 16

its held in active site by temporary bonds between r groups

Question 17

what does the substrate form in lock and key?

Answer 17

enzyme substrate complex

Question 18

what is the substrate converted to in lock and key?

Answer 18

the product enzyme product complex

Question 19

what happens to the product in lock and key?

Answer 19

r groups don’t interact product and substrate is released

Question 20

what happens to the enzyme at the end of lock and key?

Answer 20

it remains unchanged

Question 21

what is different about induced fit?

Answer 21

active site is not complementary

Question 22

how does the substrate bind in induced fit?

Answer 22

it collides and the enzyme slightly changes to fit

Question 23

how is the substrate held? (induced fit)

Answer 23

oppositely charged groups (ESC)

Question 24

what do the oppositely charged groups do?

Answer 24

put strain on the substrate increase reaction rate

Question 25

what forms in active site? (induced fit)

Answer 25

product is formed and is released due to it having a different shape

Question 26

what do enzymes do to a reaction?

Answer 26

lower activation energy speed up reaction rate hold the substrate in a way to speed up reaction

Question 27

what do enzyme reactions end with?

Answer 27

product formed or substrate conversion

Question 28

how is product of an enzyme reaction measured?

Answer 28

oxygen can be measured using a gas syringe

Question 29

how is substrate conversion measured? starch into maltose?

Answer 29

add iodine follow loss of blue colour with colourimeter

Question 30

how does enzyme conc affect the reaction?

Answer 30

increases rate of reaction until no enzymes left

Question 31

why does enzyme conc increase reaction rate?

Answer 31

increases the number of active sites more products can be formed increase reaction rate until all sites are filled

Question 32

how does excess enzyme and substrate affect the reaction?

Answer 32

enzyme conc increases so does reaction rate its directly proportional

Question 33

why does excess enzyme and substrate affect reaction?

Answer 33

enzyme conc increases active site number more products are formed reaction rate increases

Question 34

how does substrate conc affect reaction rate?

Answer 34

substrate conc increases rate until substrate has no further effect

Question 35

why does substrate conc affect rate?

Answer 35

collisions between substrate and enzyme increases more products form rate increases. more substrate has no effect enzymes are at V MAX

Question 36

how does temp effect reaction rate?

Answer 36

temp increases reaction rate this happens gradually optimum temp is reached past this reaction rate decreases

Question 37

why does temp effect reaction rate?

Answer 37

temp increases so does kinetic energy more collisions occur. more ESC is formed. optimum temp where collision are at their highest.

Question 38

what happens past optimum temp?

Answer 38

enzyme vibrate until tertiary structure breaks enzymes are denatured site is no longer complementary rate decreases

Question 39

how does pH affect reaction rate?

Answer 39

pH increases reaction rate does also until optimum pH past this reaction rate decreases.

Question 40

what is pH a measure of ?

Answer 40

number of H+ ions

Question 41

what do H+ ions do to hydrogen bonds?

Answer 41

they interfere with hydrogen bonds, ionic bonds and r groups of some amino acids.

Question 42

how does pH affect the enzyme?

Answer 42

it can alter the tertiary structure changing the active site therefore ESC cant form rate decreases

Question 43

what do inhibitors do?

Answer 43

reduce rate or stop enzyme catalysed reactions

Question 44

how do competitive inhibitors work?

Answer 44

have a similar shape compete for the active site. occupy the site stop ESC formation reduce reaction rate

Question 45

what will increasing the substrate conc do to the competitive inhibitor?

Answer 45

reduce its effectiveness more likely a substrate will bond

Question 46

where do non competitive inhibitors bind?

Answer 46

allosteric site

Question 47

how are non competitive different to competitive?

Answer 47

they do no compete they alter the active site so substrate cant bond increasing substrate has no effect

Question 48

what is end product inhibition?

Answer 48

end product binds to enzyme away from the active site and alters the shape of the active site initial substrate cant bond

Question 49

what is end product inhibition similar to?

Answer 49

reversible non competitive inhibition

Question 50

what are inborn errors of metabolism?

Answer 50

if the DNA within a enzyme is mutated enzyme may not function

Question 51

what are diseases caused by a disfunctioning enzyme in a metabolic sequence called?

Answer 51

in born errors of metabolism