Investigating Membrane Permeability Essay Example

the writer will explain the result and analyse.

Practical 1 Objective: •To predict how temperature damages the beetroot membrane Background: •In the previous page Materials: •3 Cutted beetroot •15 ml fresh water (each in test tube) •2 Bunsen burners •3 Thermometers •3 Beaker glasses •3 Test tubes •3 Stopwatches •Stirrer •camera Methods: •Turn on the bunsen burners, then place the beaker glasses on them •One beaker glass must be 70o C and another one must be 65o C and the last must be room temperature (± 25o C). ll beaker glasses contain 10 ml water •After each beaker glasses reach their temperature, place the cutted beetroots one for each of them in the same time •Set the stopwatches for 1 minute. While waiting, place the 15 ml of water in each test tube •After 1 minute, withdrawn the cutted beetroots one in each test tube and set the stopwatches for them 15 minutes. •Label the test tube in order to prevent from changing data •After 15 minutes, stir the test tubes with stirrer, in order to ‘diffuse’ the pigment to occupy the entire test tube •Then take a picture for each of them.

Result: Analysis: At high temperature molecules vibrate faster.

The water will expand too, putting pressure on the membranes. Lipids become more fluid as temperature increases so the membranes become more fragile. Proteins, if heated too much, will denature due to their hydrogen bonding being disrupted because of the vibrations. This will destroy membrane integrity and leave pores that will allow pigment leakage. The membrane becomes more permeable at higher temperatures. The proteins denature with high temperatures and the structures of the phospholipids

are less stable.

At 43 degrees there is relatively little leakage due to the proteins being below their critical temperature. Conclusion: From the results above, we can conclude that, the beetroot membrane at 70oC has the worst damage among the entire experiment. The writer concludes based on the concentration of Betalain pigments in the water, it is more concentrated at 70oC. and for the result at room temperature, based on the visible vision, there’s no contrast leakage, means, the membrane is not broken. Practical 2 Objective: •To know how the pH and detergent damage the beetroot membrane Background: At the first page Materials: •3 cutted beetroot plants •10 ml of HCl, NaOH (0.

1 mol) and 5% concentration detergent •3 beaker glasses •15 ml water for each test tubes •3 test tubes •3 stopwatches •Stirrer •Camera Methods: •Place HCl, NaOH, and detergent in each beaker glasses •After that, also place the cutted beetroot, one for each beaker glasses •Set time for 1 minute. While waiting, place the 15 ml water for each 3 test tubes •After 1 minute, withdrawn the cutted beetroot and place them in the test tube, one for each. •Then set 15 minutes.

After that, stir the water in order to ‘diffuse’ the pigment to occupy the test tube Result: Analysis: Membrane, we can say that they are built from many proteins. Then, extreme pH denatures membrane proteins because it interferes with their hydrogen bonding. Proteins tend to stabilize pH hence their hydrogen bonding can be altered.

The lower the pH the more protein denatures. That means there are holes in the membranes, which allow pigment leakage. High pH also denatures membrane

channel proteins and this is why some pigment leakage can be seen initially.

The pigments normally can't cross the membrane due to their size and their polarity.

And detergents are amphipathic molecules, meaning they contain both a non-polar "tail" and a polar "head". They are a class of molecules whose unique properties enable manipulation (disruption or formation) of hydrophobic-hydrophilic interactions among molecules in biological samples. In biological research, detergents are used to lyse cells (release soluble proteins) and make membrane proteins and lipids more soluble.

Like the components of biological membranes, detergents have hydrophobic-associating properties as a result of their non-polar tail groups. Nevertheless, detergents are themselves water-soluble. Consequently, detergent molecules disperse and liquefy water-insoluble, hydrophobic compounds.

They dissolve phospholipids and extract membrane proteins meaning that holes are left in the membrane that allow passage of pigments. Conclusion: Theoritically, more concentration of these substances (HCl, NaOH, and detergent) will make more damage in the membrane cell.

But the difference between these substances’ effect on the beetroot’s membrane cell’s disrupted is, the way how these substance break the membrane. HCl has lower pH properties, it’ll make the proteins denatured and make holes in the membrane cell, while NaOH, which has higher pH, will damage the channel proteins and makes the pigments leak. And the detergent molecules liquefy and disperse the hydrophobic compounds. Or the writer conclude, that detergent disrupts the formation of the beetroot membrane cells that make the membrane opens and make holes, then the pigments will leak out.