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Beetroot Experiment - Cell Membrane - Types of Diffusion

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Meera

Beetroot Experiment

Background Info

Cell Membrane: The cell membrane is made up of lipids, carbohydrates and proteins. The lipids are the phospholipid bilayer which consists of a hydrophilic polar head which is on the outside of the structure and a hydrophobic tail are facing inwards. Along with the proteins in the cell membranes are integral proteins and peripheral proteins. Lipids increase in fluidity as temperature increases. Once denatured, proteins start to unravel and are unable to carry out their function

Types of diffusion:

Facilitated Diffusion: Molecules which are larger than a Carbon dioxide molecule cannot diffuse through the bilayer. Instead they diffuse with the assistance of facilitated diffusion. They diffuse through the water-filled pores within the channel protein. Different channel proteins are used to transport different molecules. Every channel protein has a very specific shape which only allows exact shaped molecules to fit. Some channels need a molecule to bind to it for it to be activated (gated channel), some channels need the enzyme to fit into the protein for it to be activated or channels can be deactivated to create a balance in the cell. Proteins can also play the part of a carrier protein. The molecule or ion would bind to the active site on the protein and the protein would change shape. This would then lead onto the molecule or ion moving across the membrane. This is passive transport due to it not needing any energy.

Osmosis: is the movement of water from a region of higher concentration to one of lower concentration. Osmosis often occurs across a membrane that is semi permeable. A semi permeable membrane lets only certain molecules pass through while keeping other molecules out.

Active transport: Substances that move against the concentration gradient, moves from low to high concentration this will require energy. The energy comes from respiration and is supplied by the ATP molecule. The substance to be transported binds to the carrier protein. Energy from the ATP changes the shape of the carrier protein then releases it on the other side of the membrane. Exocytosis and Endocytosis: Cells can also be transported on the surface of the membrane. Endocytosis is when substances are taken into the cell by the creation of vesicles. Parts of the cell membrane engulfs the solid or liquid to be transported. Ecotcytosis release the substances from the vesicle and bind with the cell membrane.

Structure of the beetroot-betanin is the dye found in beetroot. Beetroot contain Betanin which are red pigments present in the cell vacuole. Betanin are souble in water and they contain nitrogen. Betanin extracted from beetroot is commonly used as food dye.

what can effect an enzyme:

Temperature: the higher the temperature, the more kinetic energy therefore more successful collisions between enzymes and substrates but after the optimum temperature, enzymes start to denature as there is so much kinetic energy bonds break therefore change shape of active site so no longer able to fit to substrate (denatured)

PH: there is an optimum pH. If you go more acidic than that there excess of H+ ions will interfere with change on enzymes active site which causes repelling of enzyme and substrate.

Substrate concentration: the higher the substrate concentration, the faster they will work as more substrates are available for enzymes to work with. But then it will start levelling off at certain rate as the limiting factor will be enzyme number, as there are not enough of them.

H1- As the temperature increases the diffusion of dye will increases. So will show a positive correlation between the temperature and the diffusion.

H0- The temperature does not affect the diffusion of dye.

Equipment:

- Colorimeter - Water baths

- Cuvette - Measuring cylinders

- Test tubes

- A beetroot

Method :

1) Cut 5 bit of beetroot from a single beetroot using a size 4 cork borer.

2) Place the slices of beetroot in a beaker of distilled water and leave overnight.

3) Fill 5 boiling tubes with 5cm³ distilled water and leave in baths of water with temperatures of 0 degrees(below Room temp), 23 degrees (Room temperature), 44 Degrees,60 degrees and 72 degrees for 5 minute.

4) Then place 1 beetroot slice in each and leave for 30 minutes

5) Pour out 2cm3 of distilled water and place into the colorimeter, adjust until it reads 0absorbance for clear water. Make sure that cuvette is facing the colorimeter , the clear side is facing the light.

6) After 30 minutes pour the 5 separate liquids into 5 new boiling tubes. Make sure not the squeeze the beetroot. Measure out 2cm³ of each and pour into cuvettes and place into colorimeter.

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