List out the materials required for observing nucleus in onion peel and cheek cells and write you observation?
1)Types of experiment
2) Materials used
3)Observations
please answer me telisthene cheppandi
Answers
Aim
To prepare stained temporary mounts of
onion peel and
human cheek cells and to record observations and draw their labelled diagrams
Materials Required
Onion, slides, coverslips, watch glass, petridish, forceps, needles, dropper, glycerine, blotting paper, blade/knife, safranin solution and a microscope.
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Aim
To prepare stained temporary mounts of
onion peel and
human cheek cells and to record observations and draw their labelled diagrams.
Theory
Plant cell to be studied in lab: Onion peel
The cells are very clearly visible as compartments with prominent nucleus in it.
The cell walls are very distinctly seen under the microscope.
The big vacuoles are also seen in each cell.
The cells can be stained very easily using safranin solution.
Animal cell to be studied in lab: Cheek cell
The cells are flat and irregular in shape, with no cell wall.
The nucleus can be seen very prominently in the center of the cell.
The nucleus of the cell is stained easily with the methylene blue stain.
The cell membrane and the cytoplasm can also be studied through these cells.
Functions of the Organelles:
Nucleus: Contains nucleic acid, DNA (genetic material) , which controls cell activities
Cytoplasm: Most chemical reactions take place here; controlled by enzymes
Cell membrane: Controls substances that move in and out of cell. It is partially permeable.
Cell wall :It is made up of cellulose, strengthens and protects the cell and gives definite shape to the cell.
Chloroplasts: Contain chlorophyll, which absorbs light energy and is a site for photosynthesis.
Mitochondrion: Site of respiration. It is known as the powerhouse of the cell.
Vacuole: Large, and filled with cell sap to help keep the cell turgid. Acts as a store of water, sugars, in some cases, of waste products that the cell needs to excrete.
A. To prepare stained temporary mount of onion peel.
Materials Required
Onion, slides, coverslips, watch glass, petridish, forceps, needles, dropper, glycerine, blotting paper, blade/knife, safranin solution and a microscope.
Procedure
Take a medium sized onion, cut its outer surface with knife.
Use forceps to remove the peel of onion.
With the help of needle separate the small portion of epidermis (peel)
Keep dilute safranin solution in a watch glass.
Put this small peel in this watch glass with brush and allow it to stain for 3-5 minutes.
Transfer the stained peel to another watch glass that contains distilled water in it, to remove extra stain.
Take a clean dry slide and place two drops of water/glycerine on the centre of the slide.
Transfer the stained peel with needle and brush on the middle of the slide, if the peel curls straighten it and flatten it with brush and needle, do this gently.
With the help of blade cut the peel into a square shape.
Take a dry and clean coverslip and gently place it on the slide with the help of needle such that no air bubbles enter in it.
Gently press the coverslip with needle for even spreading of glycerine.
Remove the extra stain and water with the help of blotting paper.
Slide of Onion Peel and Cheek Cells 1
Clean the sides of the coverslip with dry blotting paper and place it under the lens of the microscope and record your observations.
Observations
The cells under observation are the plant cells. It consists of cell wall and large vacuoles. The nucleus is very prominent and is clearly visible.
Hope it helps you by the way meru Telugu a..