C1.1 - determining reaction rates on an enzyme catalysed reaction (2k)

Question 1

what are 3 ways enzyme reaction rates can be determined?

Answer 1

• time taken for substrate to be used up
• amount of product formed or substrate used in a set time period
• initial rate of reaction

Question 2

how can you use time taken for substrate to be used up to calculate rates?
how is accuracy improved?
what are the pros and cons?

Answer 2

rate is calculated by dividing 1 by the time taken
- accuracy is improved by increasing frequency of samples

pros - qualitative indicator and data
cons - end point is subjective, relies on regular sampling and time inefficient

Question 3

how can you use time amount of product formed to calculate rates?
what are the pros and cons?

Answer 3

volume or mass gained or lost in a reaction

pro - only requires measurements at the start and end of the reaction time
con - long enough time to measure accurately, but not too long for it to be a limiting factor

Question 4

how can you use initial rate of reaction to calculate rates and what are the pros and cons?

Answer 4

calculated from a product-time or substrate-time graph

• accuracy can be improved by taking more frequent readings

pro - initial rates not affected and doesn’t need to reach completion
con - measurements must be repeated, analysis is a long process, suitable for quantified reactions