Factors affecting enzyme activity

Question 1

What is the effect of raising temperature? Why does this happen?

Answer 1

increases Ke of particles particles

collide faster and more frequently

results in more frequent and successful collisions between particles

increases rate of the reaction

eventually denatures at the temperatures goes past a certain point, decreasing enzyme activity

Question 2

What is Q10?

Answer 2

the temperature coefficient (Q10) of a process is a measure of how much the rate of a reaction increases with a 10K rise in temperature

for enzyme-controlled reactions this is usually taken as two, which means that the rate of reaction doubles with a 10K temperature increase

Question 3

What causes temperature denaturation?

Answer 3

higher temperatures causes bonds holding the protein together to vibrate more the bonds strain and then break as the vibrations increase

this results in a change of the tertiary structure of the protein,

may cause it not function properly the active site changes shape and is no longer complementary to the substrate

Question 4

What is the optimum temperature?

Answer 4

the highest the enzyme activity is before it denatures and enzyme activity decreases around 40 in humans

Question 5

How are enzymes adapted to temperature extremes?

Answer 5

cold: less stable more flexible around active site denature at lower temperature changes
hot: more stable increase no. of bonds particulary H and sulfur bridges in tertiary structure

Question 6

How are enzymes effected by pH?

Answer 6

hydrogen bonds and ionic bonds between amino acid R-groups hold proteins in their precise three-dimensional shape

Question 7

What does a change in pH change?

Answer 7

concentration of H+ ions more H+ in acidic conditions the active site will only be the right shape at a certain H+ concentration

Question 8

How does pH cause denaturation?

Answer 8

if the pH passes a certain point, it is irreversibly altered and unable to be complementary to the active sites

Question 9

How does pH effect the bonds?

Answer 9

interact with polar and charged R-groups

therefore changing the concentration changes the degree of this interaction the

more H+ ions the less R-groups are able to interact with eachother

Question 10

what pH does amylase work best at and what is its function and where is it found?

Answer 10

7-8 (neutral)

mouth/throat in saliva

starch -> maltose

Question 11

What pH does pepsin work best at, where is it found and what is its function?

Answer 11

1-2 s

tomach in gastric juice

protein -> polypeptides

Question 12

What is the pH of the pancreatic juice, what enzymes are found there and what are their functions and where is the pancreatic juice found?

Answer 12

small intestine / duodenum

pH 8

trypisn - proteins

lipase - triglycerides -> glycerol + fatty acids

amylase - starch maltase - maltose

Question 13

How does increasing the concentration of substrate increase the rate of reaction?

Answer 13

higher collision rate with the activbe sites of enzymes and the formation of more enzyme-substrate complexes

Question 14

What is Vmax?

Answer 14

when all active sites are occupied by substrate molecules and no more enzyme-substrate complexes can be formed

Question 15

What is a cofactor?

Answer 15

any inorganic ion t hat increases the activity of an enzyme