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Flashcards in Core Practical 3 Deck (6)
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1

What are we investigating?

Investigate membrane structure, including the effect of alcohol concentration or temperature on membrane permeability.

2

How will we assess membrane permeability?

- 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

How can we assess how much pigment has leaked out?

By using a colorimeter, a device which measures how much light is absorbed by a coloured solution.

4

What makes this experiment valid? (controlled variables)

- same beetroot used
- same amount of water
- beetroot kept in same conditions
- same ages beetroot.

5

How do you calculate percentage error?

(uncertainty / reading) x 100

6

what do the results show?

- 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.