Enzymes:
• Enzymes act as biological catalysts
• A catalyst is a substance which increases the speed of a reaction without
being changed or used up in the reaction
• Substrate- molecule changed in reaction
• Active site- where enzyme joins to substrate to catalyse reaction
• Enzymes have high specificity for their substrate
• Substrate has to fit into enzyme for reaction to be catalysed
Temperature:
Higher temp increases rate of reaction
Too hot active site changes shape,
Enzymes break down big
enzyme is denatured
molecules-
Optimum temp
Carbohydrases convert
pH:
carbohydrates into simple
Optimum pH
sugars. E.g. amylase breaks
Too high or too low changes shape of
down starch into maltose
active site, denatures enzyme
Proteases convert proteins
Substrate Concentration:
into amino acids
Higher substrate conc, faster rate of
Lipases convert lipids into
reaction
glycerol and fatty acids
Only true up to a point, so many
substrate molecules, active sites are all
full so adding more makes no difference
Practical- investigate effect of pH on enzyme
activity
Amylase breaks down starch to maltose,
detect starch using iodine solution, starch =
blue black solution Synthesise- joining
1. Put iodine solution into each well molecules together
2. Set up Bunsen burner This also involves
3. Add amylase and pH 5 buffer solution to enzymes
tube, heat for 5 mins Simple sugar + simple
4. Add starch solution to tube and start sugar = carbohydrates
clock Amino acid + amino acid
5. Every 10 seconds, take sample from tube = protein
and add to well. When starch is not Fatty acids + glycerol =
present, solution remains brown/orange lipids
• Enzymes act as biological catalysts
• A catalyst is a substance which increases the speed of a reaction without
being changed or used up in the reaction
• Substrate- molecule changed in reaction
• Active site- where enzyme joins to substrate to catalyse reaction
• Enzymes have high specificity for their substrate
• Substrate has to fit into enzyme for reaction to be catalysed
Temperature:
Higher temp increases rate of reaction
Too hot active site changes shape,
Enzymes break down big
enzyme is denatured
molecules-
Optimum temp
Carbohydrases convert
pH:
carbohydrates into simple
Optimum pH
sugars. E.g. amylase breaks
Too high or too low changes shape of
down starch into maltose
active site, denatures enzyme
Proteases convert proteins
Substrate Concentration:
into amino acids
Higher substrate conc, faster rate of
Lipases convert lipids into
reaction
glycerol and fatty acids
Only true up to a point, so many
substrate molecules, active sites are all
full so adding more makes no difference
Practical- investigate effect of pH on enzyme
activity
Amylase breaks down starch to maltose,
detect starch using iodine solution, starch =
blue black solution Synthesise- joining
1. Put iodine solution into each well molecules together
2. Set up Bunsen burner This also involves
3. Add amylase and pH 5 buffer solution to enzymes
tube, heat for 5 mins Simple sugar + simple
4. Add starch solution to tube and start sugar = carbohydrates
clock Amino acid + amino acid
5. Every 10 seconds, take sample from tube = protein
and add to well. When starch is not Fatty acids + glycerol =
present, solution remains brown/orange lipids
