Required practicals Flashcards
(10 cards)
How could you investigate the effect of Substrate concentration on the rate of an enzyme controlled reaction?
Collect gas - gas syringe/upturned measuring cylinder
Change substrate concentration - collect gas
What variables would you control if investigating the effect of ph on rate of reaction, and how?
Temperature
Time
Substrate concentration/ volume
Enzyme concentration/ volume
Why are colorimeters ‘zeroed’ before taking actual readings?
To avoid systematic errors
Why must temperature be constant in the ‘beetroot experiment’?
Affects rate of diffusion
increased temperature increases rate of diffusion because of increased kinetic energy
Why are cut docs washed in water before being put into alcohol?
Remove excess pigment
When doing RP4 the beetroot experiment and finding pigments.
Why would different students obtain different results, even if following the same method carefully?
Natural variability of beetroot
Why is Toluidene stain used in root tip squash experiments?
Stains nucleotides blue
What is meant by ‘Mitotic index’ and how is it calculated?
Number of dividing cell / total number of cells
Why is the root tip left in acid prior to staining? RP2
kills the cells stopping them dividing
Why do inhibition zones have a ‘halo zone’? RP6
antibiotic diffuses
