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Flashcards in Core Practical 3 Deck (6)
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What are we investigating?

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


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.


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.


What makes this experiment valid? (controlled variables)

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


How do you calculate percentage error?

(uncertainty / reading) x 100


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.