Biology Lab - to Observe and Draw Transverse Sections of Parenchyma, Collenchyma, Sclerenchyma, Xylem, Phloem and Epidermal Cells Using a Light Microscope.

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  • Topic: Cell, Phloem, Plant cell
  • Pages : 4 (1324 words )
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  • Published : December 17, 2012
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Syllabus topic: Cell structure
Aim: To observe and draw transverse sections of parenchyma, collenchyma, sclerenchyma, xylem, phloem and epidermal cells using a light microscope. Apparatus and Materials: Light microscope; microscopic slide of dicotyledonous stem Method:

1. The light microscope was plugged into a power source, and switched on. 2. The coarse focus of the light microscope was adjusted with both hands to move the stage downwards. 3. The slide with the dicotyledonous stem section was placed on the stage, and secured with the clips. 4. The 4x objective lens was selected, and the coarse focus was adjusted with both hands to move the stage upwards. When the stem section was visible, it was centred in view using the position controls on the stage. 5. The coarse control was adjusted to move the stage downwards, and the 10x objective lens was selected. When the section was in focus, the position controls were used to centre the epidermal cells in view. 6. Step 4 was repeated, with the 40x objective lens being selected. The fine focus was adjusted with both hands to produce a sharp image. 7. Three epidermal cells were drawn on paper using a fine-point pencil. 8. Steps 4-7 were repeated for each type of cell.

Results:
Cell| Length/graticule units|
Epidermal| 15|
Parenchyma| 40|
Collenchyma| 16|
Sclerenchyma| 20|
Xylem| 15|
Phloem| 20|

Table Showing Length of Epidermal, Parenchyma, Collenchyma, Sclerenchyma, Xylem and Phloem Cells

Drawings:
Drawings on following pages.

Discussion:
Plant cells are surrounded with a tough, slightly elastic wall of cellulose. Within the cell wall is the cell surface membrane, which is selectively permeable and controls the movement of substances into and out of the cell. The cytoplasm contains the organelles of the cell, as well as chemicals required for respiration and growth, along with the products of reactions within the cell. The nucleus controls the cell’s...
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