Temperture's Effect on Beet Membranes

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Temperture's Effect on Beet Membranes

Aim:

To investigate the effect of temperature on membrane structure

Hypothesis: The higher the temperature, the greater the amount of

pigment that leaves the beetroot cell.

1. An increase in temperature increases the kinetic energy of the

molecules within the cell, raising the rate of diffusion of

pigment out of the cell across the differentially permeable cell

membrane.

2. A further increase in temperature will cause the protein

molecules in the cell membrane to change shape, i.e. becoming

denatured. As a result, the red pigment in the vacuole will,

together with the cytoplasm, leak out through the damaged

membrane. Colour leakage will hence increase more significantly.

Apparatus and procedure

Alterations to the procedure

To wash away excess dye, the newly cut beetroot slices are not left

overnight but 2 minutes only, in order to save time.

Identifying variables:

Independent Variable

Dependant Variable

Controlled Variable

Temperature

Colour absorbency

Beetroot

Diameter and length of beetroot slices

Volume of water in each boiling tube

Time for washing away excess dye

Time for each boiling tube of water to equilibrate in each water bath

Time each boiling tube of water and beetoot was left in each water

bath

Safety precautions

1. Take care using the knife and cork borer.

2. Wear safety goggles in case splashes of red pigment enter your

eye.

3. Handle hot boiling tubes carefully.

Results

Temperature/°C

Colour Absorbency/A

0

0.03

10

0.02

30

0.06

40

0.23

50

0.92

60

1.85

70

1.76

A graph of colour absorbency against temperature is plotted to

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