|
|
This is only a preview of the paper
Click here to register and get the full text.
Existing members click here to login
|
|
|
Biology Coursework
A table to show the % transmission when segments of beetroot were placed into different concentrations of Ethanol for 10 minutes.
Ethanol Concentration
(%) Transmission (%) Mean Transmission
(%) Standard Deviation
(%)
Trail Number
1 2 3 4 5
0 100 100 100 100 100 100. ... 10
When looking at the table above, it is clear that as the ethanol concentration increases the amount of beetroot pigment which diffuses through the phospholipid bi-layer increases.
To work out the mean and standard deviation I used the following formulae:
Mean or (x) = ∑x
n
Variance or (VAR) = ∑(x-x)2
n
Standard Deviation = √VAR
x = Transmission %
n = Number of transmissions (5)
A table to show the Mean transmission, Variance and the Standard Deviation of the different concentrations of Ethanol.
Ethanol Concentration (%) Mean Transmission
(%) Variance Standard Deviation
0 100. ...
There are many ways of crossing the phospholipid bi-layer, and in this experiment, the beetroot pigment (Anthocyanin) passes through the gaps created in the phospholipid bi-layer by the ethanol concentration by diffusion. ...
Also ethanol was added to the beetroot. As ethanol is an organic solvent; the lipids in the phospholipid bi-layer would become soluble in the ethanol and start to break up the bi-layer. ... As a result, they will not mix freely with water molecules and so become soluble in some organic solvents – which include ethanol.
Beetroot was chosen for the experiment because the pigment anthocyanin is red and is easy to see when the anthocyanin has diffused across the membrane. ... 100% ethanol concentration will result in a lower % transmission reading on the colorimeter. ... 20% ethanol concentration will result in a higher % transmission reading.
Reason For The Reaction
When the beetroot is placed in water or a very low concentration of ethanol, no pigment or very little pigment is found when measuring the transmission of light through the substance i. ... As the ethanol concentration increases, the ethanol starts to break up the bi-layer and the bi-layer becomes soluble in the ethanol, which then starts to create large gaps in the bi-layer and these gaps are then large enough for the anthocyanin to diffuse across. ... This is because the ethanol has not yet dissolved the phospholipid bi-layer, therefore, the anthocyanin pigment has not diffused through the membrane. ... This means that gaps have started to appear in the phospholipid bi-layer because the ethanol concentration is now concentrated enough to dissolve the bi-layer, therefore, leaving big enough gaps for the anthocyanin to diffuse across. ... This shows that the damage to the membrane will increase as the % ethanol concentration increases but this will not be proportional. So the higher the ethanol concentration, the more damage to the membrane and so a greater rate of diffusion of anthocyanin out of the cell which will then result in a darker red solution.
In conclusion, my results were as expected with a low concentration of ethanol e. ... 40% whereas a high concentration of ethanol e. ... This tells me that more damage was done to the membrane as the concentration of ethanol increased. Also my results are accurate as the standard deviation at 20% ethanol concentration was 0.80, 40% ethanol concentration was 3.43, 60% ethanol concentration was 3.19, 80% ethanol concentration was 3.14 and 100% ethanol concentration was 1. ...
After collecting and correlating my results, I have come to the conclusion that the experimental hypothesis is correct in that an increase in ethanol concentration will damage the plasma membrane and cause the anthocyanin pigment to diffuse out.
Approximate Word count = 2917
Approximate Pages = 11.7
(250 words per page double spaced)
|
|
|
|
|
|