RP9: Respiration Flashcards
1
Q
Why would apparatus set up to investigate respiration need to be left for a period of time?
A
- reach equilibrium
- allows for expansion/pressure changes
- allows respiration rate to stabilise
1
Q
What measurements need to be taken to calculate the volume of gas from a potometer?
A
- how far the coloured liquid moved (cm)
- diameter of cube (to calculate volume)
2
Q
What is methylene blue? How is it used in this practical?
A
- a redox dye
- acta as an alternate electron acceptor of electrons transferred in ATP synthesis
- blue to colourless
3
Q
Outline the method of this practical…
A
- set up water bath
- add equal volumes of yeast and glucose
- leave them to equilibrate for 10 minutes
- add 2cm3 methylene blue and start time, shake and place back in water bath
- record how long it takes to go colourless
repeat at different temps
4
Q
Why is the yeast solution buffered?
A
- maintain constant pH
- so enzymes function at their optimum
5
Q
How does temperature affect respiration?
A
increase in temp increases rate until a certain point
