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### The Effect of Different Temperatures on the Permeability of Beetroot Cell Membrane

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The Effect of Different Temperatures on the Permeability of Beetroot Cell Membrane

Aim- to investigate the effect of different temperatures on the
permeability of beetroot cell membrane.

Prediction: I think that the higher the temperature the higher the
absorbance of the liquid into the beetroot membrane.

Table of results
================

Average temp

(ºC)

Group 1 absorbance

(Arbitrary units)

Group 2 absorbance

(Arbitrary units)

Group 3 absorbance

(Arbitrary units)

Average absorbance

(Arbitrary units)

25

0.05

0.26

0.13

0.14

35

0.16

0.34

0.09

0.19

45

0.27

0.21

0.19

0.22

55

0.57

0.63

0.29

0.49

65

0.73

2

0.38

1.03

75

1.37

2

0.49

1.28

85

1.66

2

1.94

1.86

Statistical analysis
====================

Spearman rank correlation
-------------------------

The reason for the statistical analysis is to find out if group 1, 2
and 3 and average absorbance is a positive or negative correlation or
no correlation at all.

Group 1

In group 1 each absorbance was increased when the temperature was
increased so the rank was not changed therefore the rs was 1. This
means it is over the critical value (0.79) therefore there is a
positive significant correlation between the two values.

Group 2

Site

Temp

(ºC)

Rank

R1

Absorbance

(Arbitrary units)

Rank

R2

D

(R1-R2)

D2

1

25

1

0.26

2

-1

1

2

35

2

0.34

3

-1

1

3

45

3

0.21

1

2

4

4

55

4

0.63

4

0

0

5

65

5

2

6

-1

1

6

75

6

2

6

0

0

7

85

7

2

6

1

1

0

8

From using the formula the rs was 0.85, which is over the critical
value (0.79) therefore there is a positive significant correlation
between the two values.

Group 3

Site

Temp

(ºC)

Rank

R1

Absorbance

(Arbitrary units)

Rank

R2

D

(R1-R2)

D2

1

25

1

0.13

2

-1

1

2

35

2

0.09

1

1

1

3

45

3

0.19

3

0

0

4

55

4

0.29

4

0

0

5

65

5

0.38

5

0

0

6

75

6

0.49

6

0

0

7

85

7

1.94

7

0

0

0

2

From using the formula the rs was 0.96, which is over the critical
value (0.79) therefore there is a positive significant correlation
between the two values.

Average absorbance

In the average absorbance each absorbance was increased when the
temperature was increased so the rank was not changed therefore the rs
was 1. This means it is over the critical value (0.79) therefore there
is a positive significant correlation between the two values.
======================================================================

Analysis
========

Conclusion
----------

In my two graphs the overall trend is when the temperature is
increased the absorbance of the beetroot is increased. At no point in
my two graphs do you see the absorbance decreases when the temperature
is increased. For example if you look at my average absorbance graph
at 25°C the absorbance is 0.35, and at 35°C the absorbance is 0.53. So
there is an increase in absorbance.
======================================================================

A cell membrane is made up of many different molecules these include
phospholipids, cholesterol, proteins, glycolipids and glycoproteins.
Each of these all has specific functions in the cell membrane.

Phospholipids make up the basic structure of the membrane, forming a
bilayer. They have hydrophilic heads and hydrophobic tails, with the
tales being non polar its very difficult for ions and polar molecules
to pass through the membrane, so the phospholipids act as a barrier to
water soluble molecules.

Therefore the only way water-soluble molecules can get through the
membrane is through the protein. Protein in the membrane acts as
hydrophilic passage ways or transport route for ions and polar
molecules to diffuse into the membrane. Protein control what
substances enter and leave the membrane. There is specific protein
types for different substances, these are known as protein carrier
cells.

Cholesterol role is different compared to protein and phospholipids,
its role is to give the membrane support and strength. Cholesterol
determines how fluid the membrane is. It helps to control the
fluidity, stopping it from becoming too fluid or too rigid, preventing
the membrane from bursting. Cholesterol structure is very similar to a
phospholipid, it too has a hydrophilic head and hydrophobic tale,
which allows it to fit neatly in the phospholipids.

Glycolipids and glycoproteins role is to help stabilise the
membrane, with their carbohydrate chains that extend out into the
water surface forming hydrogen bonds with the water molecules.

[IMAGE]

In the experiment the diffusion between the beetroot membrane and the
solution stayed the same in terms of the kinetic energy being the same
having no effect on the leakage of the membrane. So the kinetic energy
of the diffusion never changed and didn’t affect the experiment. So
the leakage was at room temp as the beetroot cylinders was only heated
for 1 minute, so they cooled back down when the leakage occurred. But
the reason why the leakage was different for the beetroots at
different temperature was during the 1 minute they were heated a
molecule in the membrane was permanently damaged.

I believe the molecule that was permanently damaged was the proteins
in the membrane. My reason for this is a protein is affected by
temperature, when temperature is increased the 3D shape of the protein
is changed causing it to become denatured. Proteins are hydrophilic
channels for ions and polar molecules, also allowing certain
substances enter and leave the membrane and if the proteins specific
shape is changed this will cause the cytoplasm and other substances
contained within the membrane to leak out. This has been shown by a
steady increase in anthocyanin (polar molecule) leaked out of plant
cells as the temperature increases. So this is what has caused more
leakage from beetroot cells. The higher the temperature the more the
protein has changed in shape, which is the reason for the absorbance
increasing when beetroot is heated at higher temperatures. At low
temperatures such as 35ºC-45ºC the 3D shape of the proteins isn’t
changed too much, so not much leakage takes place. So there was more
diffusion of the anthocyanin in higher heated beetroot cells, but that
was due to the shape of the protein being changed, not the kinetic
energy.

Also during the 1 minute the beetroot membrane was heated the
phospholipids were changed but this was only temporary, once the
beetroot was back at room temperature the phospholipids changed back
to their original form. What happens is at high temperatures the
phoispholipids don’t fit together as easily, as the membrane becomes
more fluid. This means there is a slight chance of substances getting
through past gaps between the phospholipids, but most of the time they
still acted as a barrier to ions and polar molecules even if there was
gaps between them. If any anthocyanin did leak out through the gaps of
the phospholipid or if the phospholipid burst when heated it would
have leaked into beaker, which wasn’t measured. Only leakage at room
temperature was measured.

Evaluation

Evaluation of procedure

The things that were kept the same to be a fair test are:

1. The beetroot was cut 21mm every time to allow the same surface area
at each different temperature.

2. Using a thermometer to check the temperature at the start of when
the beetroot was put in the boiling water and at the end of the minute
when taking the beetroot out. This meant an average was taken for each
temperature.

3. Each beetroot was washed before being put in hot water, this was so
the beetroot juice was washed out.

4. Keeping each beetroot in the solution for the same amount of time,
which was 25 minutes.

5. Using the same sized cork borer when cutting up the beetroot.

Limitation described

Effect on result

Suggested improvement

Justification of improvement

Temperature control- the thermometer was used to measure the temp of
the water using a Bunsen burner.

Accuracy of the effect of temperature on beetroot. The temperature may
not be dead on the required temperature, so it could be a random
effect on the results

Use a thermostatic water bath.

A thermostatic water bath is much more accurate as it keeps water at
the required temperature. It could also be said that the results will
be more reliable as a better piece of equipment is used

Cutting of discs- not always cutting the beetroot straight and
sometimes cutting them vertically, causing the surface are to be
different on the beetroot cylinders

Always increasing

Take extra care when cutting the beetroot. Or use a different piece of
equipment rather than a knife such as a mini plastic mitre block or
something similar to a egg slice.

So there is less chance of the beetroot being cut vertically if it is
not rushed. This will make the results much more accurate and
reliable.

Shaking the test tubes unevenly before putting in colorimeter

It can be a random effect on the results

Shake each test tube a certain number of times before putting in the
colorimeter.

This means each test tube will be equal in the number of shakes
therefore making the results more accurate. This means the results
will be more reliable.

Washing the beetroot- some beetroot cylinders were washed more than
others.

Some beetroot will have juice still inside. It can be a random effect
on the results

Leave the beetroot in distilled water for 6 minutes

This means each set of beetroot in each test tube will be washed for
the same amount of time. This means the results will be more accurate.

Evaluation of evidence

In my average absorbance graph/table there is no anomalous/ odd
results.

But in group 2 absorbance at 65°C to 85°C the absorbance was 2
abilitrary units. This means there was an error in the colorimeter.
This could have been caused by many of faults during the method.

But I believe it may be due to the cutting of the beetroot discs not
being cut straight, and being cut diagonally which increases the
surface area therefore increase the result.

Another anomalous result was in group 3 at 35ºC where the absorbance
decreases. I believe this could have been caused by the beetroot not
being left in the water at 35ºC for one minute and was taken out to
early. Also it may not have been at 35ºC and the temperature was
lower.

Also I think same reason applies for the anomalous result at 45ºC in
group 2 and group 1.

Overall the average absorbance results looked good, as there was a
nice pattern, which formed a nice joined line on the graph and seem to
be reliable. The reason why I think this is group 1 absorbance had
excellent results, and group 3 absorbance was good it was only group 2
absorbance that had a lot of anomalous results. There was no mistakes
in group 1 as that was my group, we did every thing the best we could
and being very careful.

Percentage of errors

The formula that is used to find out due to measuring equipment is:

Minimum measurement

Actual measurement

Errors due to thermometer

25ºC

So you apply the formula above:

Now add and subtract 4% of 25ºC (which is 1) to 25ºC.

1 + 25=26

1- 25=24

85ºC

Now add and subtract 1.2% of 85ºC (which is 1.02) to 85ºC

1.02 + 85= 86.02

1.02 + 85=84.02

Errors due to absorbance

Many instruments contribute to absorbance error, these are::

Lowest point Highest point

· Ruler (21mm)
4% 4%

· Syringe (10cm3)
5% 5%

· Clock (1min) 2%
2%

· Colorimeter
7% 0.53%

Lowest point Highest point

Compound error
18% 11.53%

The percentage of error of the thermometer isn’t too bad, it doesn’t
effect the results that and shows the thermometer is quite reliable.

The absorbance compound error at my highest point had a major effect
on the result, it shows the equipment used for absorbance cause a
massive error, as show on my average absorbance graph. While at the
lowest point shows the compound error is high (17%), and has a major
effect on the result. The percentage of errors of the equipment puts a
question mark on the accuracy and reliability of the results.

MLA Citation:
"The Effect of Different Temperatures on the Permeability of Beetroot Cell Membrane." 123HelpMe.com. 04 Dec 2013
<http://www.123HelpMe.com/view.asp?id=148667>.