Practical 1 - effect of temp on enzymes Flashcards
what is a buffer solution
Solution that resists any change in PH
how to calculate mitotic index
number of dividing cells/ Total umber of cells
why was a root tip used in RP2
where dividing cells are/growing occurs/ mitosis is
why was a stain used on the root tip cells in RP2
To stain the DNA + so we can see the chromosomes clearly and determine what stage there in
why was the root tip firmly squashed in RP2
To let light through / thin layer + so optical microscope can work
Why would another investigation on a different garlic root tip provide different results/Mitotic index ?
Different time of day
Different type of garlic species
equation for percentage change in mass
change in mass / original mass x 100
what is the advantage of giving results as percentage change in RP3
Change in mass is comparative despite different starting masses
why does taking additional readings increase reliability of a investigation
reduce effect of anomalies / can identify anomalies
find a mean
on a graph of percentage mass change against concentration of salt solution how do you find the water potential of inside the potato - RP3
Where the line of best fit meets the x axis/ there is no change in mass at that conc of solution + the water potential inside the potato cells
what is a colorimeter
measures absorbance of light in a liquid
the higher the absorbance of the light the more concentrated the solution
what type of graph is used to convert absorbance values into concentration values in RP4
calibration curve
describe the aseptic techniques required to transfer bacteria onto agar plate - RP6
- Flame neck of bottle
- use sterilised pipette
- open lid of agar plate facing Bunsen burner
- use Spreader in ethanol to spread round
In RP6 why is the agar plate with bacteria kept at 25 C in incubator and not higher
lower temp avoids pathogenic bacteria growing
how to calculate Rf value
distance travelled by pigment / distance travelled by solvent
