enzymes and kinetics

Question 1

what are enzymes ?

Answer 1

catalyses all biochemical reactions

play a role in metabolism , diagnosis and therapeutics

levels in blood use as indictors for disease

can be used therapeutically

Question 2

what ending of the word do enzymes usually end with ?

Answer 2

-ase

Question 3

what are the six classes of enzymes ?

Answer 3

transferases
ligase
oxidoreductases
isomerase
hydrolase
lyases

Question 4

what do transferases do ?

Answer 4

transfer functional groups from one molecule to another

Question 5

what do ligases do ?

Answer 5

join two molecules together

Question 6

what do oxidoreductases do ?

Answer 6

move electrons between molecules

Question 7

what do isomerases do ?

Answer 7

convert a molecule from one isomer to another

Question 8

what do hydrolases do ?

Answer 8

break bonds using water

Question 9

what do lyases do ?

Answer 9

break bonds without using water or oxidation

Question 10

how do enzymes act as a biological catalyst ?

Answer 10

globular protein with specific shapes

control rates of metabolic reactions

lower activation energy

not consumed in reactions

substrate specific

shape of active site determines substrate

Question 11

what is activation energy?

Answer 11

the input of energy to start the chemical reaction

Question 12

what effect does enzymes have on activation energy for chemical reactions ?

Answer 12

lowers activation energy

Question 13

what is lock and key model ? [ emil fischer 1894]

Answer 13

active site is rigid shape

only substrate with matching shape can fit

no change in active site on binding substrate

Question 14

what is the induced fit model? [daniel koshland 1958]

Answer 14

active site is flexible , not rigid

greater range of substrate specificity

Question 15

what are the factors which effect enzyme activity ?

Answer 15

enviromental conditions
temperature
ph
substrate concentration
inhibitor and activators

Question 16

what is majority of enzymes optimum temperature?

Answer 16

37 degrees

Question 17

what temperature will most enzymes denature at ?

Answer 17

70 degrees

Question 18

what is the optimum ph for enzymes?

Answer 18

7

Question 19

what happens when there is a small change in ph ?

Answer 19

change shape of active site

Question 20

when does maximum rate of activity occur ?

Answer 20

when enzymes are fully saturated

Question 21

what effect does an inhibitor have on activity of enzymes ?

Answer 21

Decreases it

Question 22

what is a reversible inhibitor ?

Answer 22

can associate and dissociate with an enzyme to regulate activity

Question 23

what is a non reversible inhibitor ?

Answer 23

Covalent attachment of the inhibitor to the enzyme

Can only be overcome by making more enzyme

Question 24

what is a competitive inhibitor ?

Answer 24

has similar substrate to the substrate

competes with substrate for active site

Question 25

how do you reduce the effect of competitive inhibitor ?

Answer 25

increasing the substrate concentration

Question 26

what is a non competitive inhibitor ?

Answer 26

substrate is diff from substrate

binds to enzyme away from active site [ allosteric site ]

changes shape of active site

Question 27

can the effect of a non competitive inhibitor be reversed by adding more substrate ?

Answer 27

cannot be reversed

Question 28

what does activator have effect on enzymes ?

Answer 28

increases activity

Question 29

where does activators bind ?

Answer 29

allosteric site

Question 30

what is metabolism ?

Answer 30

chemical reaction that occur in a living organism

conversion of one compound to another compound

Question 31

what is the purpose of metabolism ?

Answer 31

energy production

biosynthesis

excretion

Question 32

what is anabolism ?

Answer 32

synthesis from smaller to larger molecules

requires energy

provides substance for cellular growth and repair

Question 33

what is catabolism ?

Answer 33

involves breakdown of larger molecules into smaller ones

releases energy

used to decompose carbs , lipids and protein

Question 34

what are the three main sources of energy ?

Answer 34

carbohydrates
lipids
proteins

Question 35

what does glycolysis convert glucose into ?

Answer 35

pyruvic acid

Question 36

what is the net gain in which happens glycolysis

Answer 36

2 molecules of ATP per glucose molecule

Question 37

what is glycogenolysis ?

Answer 37

converts glycogen into G-6-P

G-6-P enters glycolysis

Question 38

what is TCA cycle ?

Answer 38

central to all respiratory oxidation

oxidises actyl-co A from glucose, lipid and protein catabolism in aerobic respiration

maximises energy gain

Question 39

what happens in oxidative phosphorylation ?

Answer 39

formation of ATP by transfer of electrons

major source of ATP production in aerobic organisms

Question 40

why are triglycerides important ?

Answer 40

stored energy in form of fat droplets within adipose tissue

Question 41

what process to fats occur during starvation ?

Answer 41

lipolysis

Question 42

what happens during lipolysis ?

Answer 42

switches fast carbohydrates into slow lipid energy

only brain continues to use carbohydrates

Question 43

what are the three stages of processing triglycerides ?

Answer 43

1. Triglycerides are degraded to fatty acids and glycerol in the adipose tissue and transported
   to other tissues
2. At these tissues, fatty acids are activated and transported into the mitochondria for
   degradation
3. Fatty acids are broken down into two-carbon acetyl-Co A units and fed into the TCA cycle

Question 44

where does metabolism of proteins begin ?

Answer 44

in the stomach

Question 45

where does the completed metabolism of proteins end ?

Answer 45

intestines

Question 46

what is the primary proteolytic enzyme in stomach for metabolism of proteins ?

Answer 46

pepsin

Question 47

what enzyme is secreted from pancreas for metabolism of proteins ?

Answer 47

zymogens