Core Practical 3 Flashcards
(6 cards)
1
Q
What are we investigating?
A
Investigate membrane structure, including the effect of alcohol concentration or temperature on membrane permeability.
2
Q
How will we assess membrane permeability?
A
- using beetroot cells as the vacuole contains a purple pigment , betalain.
- by putting pieces of beetroot in different temp waters we can see if temp affects the permeability of the membrane.
3
Q
How can we assess how much pigment has leaked out?
A
By using a colorimeter, a device which measures how much light is absorbed by a coloured solution.
4
Q
What makes this experiment valid? (controlled variables)
A
- same beetroot used
- same amount of water
- beetroot kept in same conditions
- same ages beetroot.
5
Q
How do you calculate percentage error?
A
(uncertainty / reading) x 100
6
Q
what do the results show?
A
- heating the beetroot pieces increases kinetic energy
- causes phospholipids to move around more
- gaps may appear in vacuole and cell surface membrane that betalain molecules can escape through
- phospholipid bilayer may potentially melt and denature.
- equilibrium is eventually reached.
