Testing for Animal cell
- Cover slip and microscope slide.
- cotton bud.
- 0.1% Methylene blue
- Filter paper
- Take a cotton bud and rub it in your mouth around the cheeks.
- On a microscope slide rub the bud to place the cells on the microscope slide.
- Pour a drop of mehtyline blue and place the cover slip carefully.
- Use the filter paper/paper towel to absorb any excess methyline.
- Then place the microscope slide under the microscope.
- Under low power/magnification you should notice tiny blue spots. Switch to high power/magnification and you will see a general animal/human cell with its nucleus, cytoplasm and plasma membrane.
- You can draw the cell structure on a piece of paper.
- Dispose of all the bio-hazard material.
Testing for Onion epidermal cell
- Cover slip and microscope slide
- 2% iodine solution
- Cut an onion into two halves. Then peel off two of its layers.
- Peel off the part which is smooth and carefully break it into two. You will notice another layer which is transparent. This is the epidermal layer.
- Peel off the epidermal layer and use the forceps to place it onto the microscope slide carefully.
- Pour a drop of the iodine solution and place the cover slip.
- Place it under the microscope and you will notice the epidermal cells under high magnification.
- You should notice the features of a typical plant cell. These are the cell wall, the nucleus, the sap vacuole and the cytoplasm.
- Draw it on a piece of paper and dispose of any bio-hazard material.
Testing for leaf cells
- distilled water.
- 3mm square of leaf
- microscope slide and cover slip
- filter paper
- Place the leaf on the microscope slide and pour a drop of water on the leaf part.
- Place the cover slip and remove excess water by filter paper.
- Observe in the microscope in low magnification.
- Observe a clear part of the cells present under high magnification.
- You can see the palisade mesophyll cells and the spongy mesophyll cells.
- Draw it on a piece of paper and dispose of the biohazard material.
Testing for Osmosis in Plants
- epidermal layer of the leaf
- Distilled water
- Cover slip and microscope slide
- Sucrose solution
- Pour a drop of water on the microscope slide. Place the epidermal layer on the water and pour another drop of water on the epidermal layer.
- Place the cover slip and remove any excess water with the filter paper.
- Place it under the microscope and under high magnification observe the epidermal cells for 10 minutes.
- There should be changes in the epidermal cells. The cells would soon become turgid.
- You can make a drawing and dispose of the bio hazard material.
Test for osmosis in potato chips
- peeled off potato chips about 7cm x 1cm x 1cm
- sucrose solution
- distilled water
- 3 test tubes
- Pour the sucrose solution in first tube and mark it. Pour water in the other and mark it. Let the third remain empty.
- Weigh each of the chips and make sure it is completely peeled. Write down the the weight on a piece of paper for later calculations.
- Dry the potato chips with paper towel/filter paper to remove moisture. Then place it in each of the test tubes for an hour.
- After an hour take out each of the potato chip by forceps, weigh it and note down its weight. You can also check for its flexibility.
- The one in the sucrose solution would not be much flexible and should weigh less than before. The one in plain water should be more flexible and should weigh more. The one without any solution is less flexible and also weighs less than before due to evaporation.
- Compare the difference in weight before the test and after the test by using addition and subtraction. You can also get the percentage of difference in weight by the formula: starter weight/weight after the test x 100%
- Dispose of the bio-hazard material.
Effect of temperature on Enzyme test
- 5 cm^3 amylase solution
- 5cm^3 starch solution
- spotting tile
- iodine solution
- 3 beakers
- boiling tube
- Pour drops of iodine solution using a pipette on the spotting tray, in each cavity.
- Pour the starch solution in one boiling tube and the amylase in the other and mark them both.
- Boil water in a beaker (half full) to 25 degrees Celsius/Centigrade, boil the other to 40 degrees Celsius/Centigrade, and let the last one remain at room temperature.
- Give a water bath to each of the solution in the beaker with room temperature water for 5 minutes.
- Pour the amylase solution into starch solution and mix it.
- Then at 30 seconds interval pour a drop of the solution on to the spotting tile.
- You will notice that when you pour a drop of the solution on to the 5th or 6th cavity the color won’t change at all.
- Repeat steps 1-2 and this time give a water bath in the 25 degrees Celsius temperature beaker. Again pour it at 30 second interval and this time you will notice that the color will remain remain same in the 3rd or 4th cavity.
- Repeat the process, this time with the one that has the temperature 40 degrees Celsius and you should notice that at the 1st or 2nd cavity the color remains the same. This indicates that the enzymes have already broken down starch into glucose and so does not react towards the iodine solution.
This proves that the temperature has an affect on the enzyme activity.