1.8- Factors affecting enzyme action

Question 1

effect of temperature

Answer 1

• rise in temp increases the kinetic energy of molecules
• more frequent collisions between enzyme and substrate
• more ES complexes formed in a given amount of time
• faster rate of reaction
• however if temp rises too much then enzymes become denatured

Question 2

effect of pH

Answer 2

• change in pH alters the charges on the amino acids that make up the active site o
• substrate and enzyme no longer have a complementary shape so substrate cannot bind to form ES complex

Question 3

effect of enzyme concentration on rate of reaction

Answer 3

• as long is there is an excess of substrate, an increase in enzyme concentration leads to a proportional increase in the rate of reaction
• however, if there are less substrate molecules than enzyme molecules then substrate concentration is the limiting factor so increasing the enzyme concentration will not increase the rate of reaction

Question 4

effect of substrate concentration on rate of reaction

Answer 4

• if enzyme concentration is fixed than an increase in substrate concentration will increase the rate of reaction because the available substrates for the enzymes to collide and form ES complexes with is increased
• however, as the substrate concentration increases further the active sites of the enzymes become fully saturated and so a further increase in substrate concentration will not increase the RoR