OBJECTIVES
The purpose of this practice is to provide an overview of the microscope and how to use it. Also to observe the differences between animal and plant cells, preparing a sample of onion epidermis and observing others samples.
MATERIAL
- Distilled water
- An Onion
- A knife
- Safranin colouring fluid
- Microscopes and loupes
- Different samples of cells
- Forceps
- A loupe
- A slide and a coverslip
- A mortar.
OBSERVING ANIMAL AND PLANT CELLS
Mouse ear
Mouse intestine
Plant cells
ONION'S PROCEDURE
Make a cut in the onion, in
order to have a piece of its epidermis.
Wash the piece well with
distilled water.
Dye the piece of epidermis
with safranin for 30 seconds.
Wash the piece again carefully;
therefore we do not damage the piece.Cover up the piece with a
slide and a coverslip.
QUESTIONS
1. Parts of a microscope:
2. DIFFERENCES BETWEEN A LOUP AND A MICROSCOPE
In the binocular loupe the three-dimensional images are observed, in the two-dimensional microscope, since the samples are cut with a micrometer and placed in a sample.A big difference is the magnification, the loupe increases by 40x (you can see things you see at first glance) and the microscope allows you to see structures such as cells and microorganisms (1000x).
The microscope has artificial light, coming from below, instead the loupe may not bring it and use it with natural light, the light will come from above.
Under the microscope the platinum can be moved and in the magnifying glass no.To see a sample in the microscope it is necessary to dye it and to prepare it and in the magnifying glass no.
3. HOW DO THE MICROSCOPE AUGMENT?
There are two lenses, ocular and objectives. To calculate the total augment we have to multiply the augments of the ocular by the augments of the objective.
4. DIFFERENCES BETWEEN ANIMAL AND PLANT CELLS.
2. DIFFERENCES BETWEEN A LOUP AND A MICROSCOPE
Plant cells
|
Animal Cells
|
|
Cell wall
|
X
|
|
Chloroplasts
|
X
|
|
Centriols
|
X
|
|
Vacuols
|
Biggers.
|
Smaller.
|
Nucleus
|
Place on one side of the cell.
|
Central position.
|
Ciotesqueletum
|
X
|
|
Flagellum
|
Some.
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