C1.1 Enzymes and Metabolism

Question 1

enzyme

Answer 1

mainly proteins that function as biological catalysts

Question 2

catalyst

Answer 2

a substance that speeds up the rate of a chemical reaction

effective in small amounts and remain unchanged at the end of the reaction

Question 3

what are enzymes

Answer 3

globular proteins

Question 4

features of a globular protein

Answer 4

rounded and spherical
functional - catalysts
mostly soluble
irregular amino acid sequence

ex. haemoglobin, insulin, catalase

Question 5

what is the shape of an enzyme determined by

Answer 5

folding of protein
amino acids in the primary structure of protein
DNA genetic code

Question 6

metabolism

Answer 6

chemical reactions in the body

Question 7

role of enzyme in metabolism

Answer 7

if there are no enzymes - reactions at slow rate
enzyme speeds up reactions

wrong collisions would occur

Question 8

what is the point of enzyme specificity

Answer 8

metabolic processes can be closely controlled

Question 9

how are enzyme specificty classified

Answer 9

according to the type of reaction they catalyse and names according to substrate

Question 10

collision in enzyme action

Answer 10

parts are in continual random molecular motion
by chance collisions will occur

Question 11

catalysis in enzyme action

Answer 11

substrates bind to the enzymes active site which undergoes induced fit to achieve the proper alignment and enable the enzyme to perform its catalytic function

Question 12

release in enzyme action

Answer 12

products leave active site
enzymes left unchanged - can be reused

Question 13

anabolism

Answer 13

synthesis of complex molecules from simpler molecules including the formation of macromolecules from monomers

building up

Question 14

examples of anabolism

Answer 14

synthesis of proteins from amino acids
synthesis of polysaccharides from sugars
photosynthesis

Question 15

endergonic

Answer 15

energy requiring reactions - anabolism

Question 16

catabolism

Answer 16

breakdown of complex molecules into simpler molecules including the hydrolysis of macromolecules into monomers

breaking down

Question 17

examples of catabolism

Answer 17

hydrolysis of macromolecules into monomers in digestion

Question 18

exergonic

Answer 18

energy releasing reactions - catabolism

Question 19

active site

Answer 19

the binding point where the substrate binds with enzyme to produce product

Question 20

enzyme substrate complex

Answer 20

temporary structure formed when a substance binds to the active site of an enzyme

Question 21

properties needed in active site

Answer 21

• binding to substrate molecule
• holding on to it during chemical reactions
• lowering energy of transition state

Question 22

induced fit

Answer 22

binding of the substrates causing slight change in the shape of the enzyme to enhance catalytic activity

Question 23

lock and key model

Answer 23

enzyme is the lock and substrate is the key

shape of the key must match lock and one key opens one lock

Question 24

hand in glove OR induced fit model

Answer 24

in induced fit model because the active site change to fit substrate to ensure optimal fit

most enzymes follow this

Question 25

why is movement needed in enzymic reactions

Answer 25

needed for a substrate molecule and an active site to come together greater the kinetic energy greater the chance of collisions

Question 26

immobilised enzymes

Answer 26

enzymes attached to an inert, insoluble material, enabling recovery, reuse and improved enzyme stability

Question 27

features of immobilised enzymes

Answer 27

- more stable - provide better environment for enzyme activity

Question 28

how do enzymes get immobilised so they dont go away

Answer 28

enzyme may be entrapped between fibres or covalently bonded to a matrix enzymes prevented from being washed away

Question 29

example of immobilised enzymes in job

Answer 29

widely used method in food processing, pharmaceuticals and waste water treatment

Question 30

enzyme immobilisation techniques

Answer 30

entrapment absorption covalent bonding cross linking affinity

Question 31

advantages of enzyme immobilisation

Answer 31

- permits reuse of enzyme preparation - product is enzyme free - more stable and long lasting due to protection

Question 32

denaturation in enzymes

Answer 32

occurs when weak intramolecular (hydrogen bonds) interactions within enzyme formed between different amino acids break changes 3D shape of active site so enzyme substrate complex can't form

Question 33

effect of temperature in enzyme reactions

Answer 33

raising temperature speeds up a reaction more kinetic energy means particles move faster and are more likely to collide

Question 34

what can extremely high temperature do

Answer 34

cause bonds of enzyme and active site to break that maintain structure it will loose its shape and stop workinge

Question 35

effect of PH in enzymes

Answer 35

bonds are vulnerable to pH each enzyme has an optimum pH for optimum rate pH change causes change in shape of active site activity of enzyme is reduced and rate of reaction slows

Question 36

activation energy

Answer 36

initial energy input in the reaction

Question 36

effect of substrate concentration in enzymes

Answer 36

increase causes rate of reaction to a certain point as there is more opportunity for collisions between enzyme and substrate once all enzymes have bound a substrate any more substrate increase will have no effect on rate of reaction

Question 37

transition state

Answer 37

point where there is maximum value of energy

Question 38

effect of enzymes on activation energy

Answer 38

all chemical reactions require energy - reactants need to have bonds weakened or broken - molecules need to be reorientated - new bonds need to be formed

Question 39

importance of bonds

Answer 39

store energy because theyre made of energyen

Question 40

how do enzymes catalyse chemical reactions by lowering activation energy

Answer 40

- wearing or breaking bonds in the substrates - reorienting atoms in the substrates - forming new bonds