Question

54 Use information on your Summary Chart (page 31) to eui mate the diameter of cheek epithelial cells. Record the total magnification (TM) used. total n Why do your cheek cells look different from those illustrated in Figure 3.5? (Hint: What did you have to do to your choek to obtain them?) mount, dispose of your wet mount p n in the beaker of bleach solution, and put the coverslips in an auto- clave bag. Figure 3.5 Epithelial cells of the cheek cavity (surface view, 630x). 10. Obtain a prepared slide of cheek epithelial cells, and view them under the Estimate the diameter of one of these check epithelial cels coverslip with a wet mount to prevent soiling the lens if you ion from the Summary Chart (page 31) The coverslip should be tight against the slide. If there is excess fluid around its edges, you will need to remove it. Obtain a piece of filter paper, fold it in half, and use the folded edge to absorb the excess fluid. You may use a twist of paper towel as an and easier to measure than those of the wet mount? towel in the disposable autoclave bag. 11. Before leaving the laboratory, make sure all other ma lenses, and put the dust cover on the microscope before you return it to the stor- 6. Place the slide on the stage, and locate the cells in low want to dim the light with the iris terials are propery diaphragm lever to provide more contrast for viewing the lightly stained cells. 3.5). Move to

Answer 1

2. True or False

(1) FALSE. The microscope lens should be cleaned with special lens tissue and not any soft tissue.

(2) FALSE. The microscope lens should be stored with scanning lens in psotion over the stage.

(3) TRUE. Use the lowest power lens when beginning to focus.

(4) FALSE. Coarse adjustment knob should be used with lowest power lens.

(5) TRUE. A coverslip should always be used with wet mounts.

Match the Following

1. (i) Stage - Platform in which the slide rests for viewing.

2. (h) Ocular lenses - lens located at the superior end of the body tube

3. (e) Mechanical stage - controls the movement of the slide on the stage

4. (b) Condenser - delivers a concentrated light to the specimen

5. (c) Fine Adjustment Knob - used for precise focusing once initial focusing is done

6. (f) Moveable nosepiece - carries the objective lenses; rotates so that the different objective lenses can be brought into position over the specimen.

7. (d) Iris diaphragm lever - used to adjust the amount of light passing through the specimen

Question Answers

4. The proper technique of transporting a microscope is by carrying it upright with one hand supporting the base and the other hand holding the arm.

5.

Virtual image - The image generated by the ocular lens after it magnifies the real image created by the objective lens

Resolution - The ability to discriminate two close objects as separate.

10.

Resolution increases within specific limits as one moves to higher magnifications with the microscope.

Amount of light needed increases as one moves to higher magnifications with the microscope.

Working distance decreases as one moves to higher magnifications with the microscope

Depth of Field decreases as one moves to higher magnifications with the microscope.

11.

The working distance for the high-power lens should be much smaller that is it should be about 0.5 mm. Therefore, the object that the student is observing is definitely not in focus.

12. The proper preocedure for preparing a wet mount is

(a) Place a drop of water or saline on a clean slide.

(b) Place the object/sample in the drop of water.

(c) Hold a cover sip at a 45 degree angle at on side of the drop and slowly lower the coverslip.

13.

(a) Only half of the field is illuminated is because the path of the light is blocked by something.

(b) The field doesn't change as the mechanical slide is moved can be due to two reasons:

(1) The working distance is much greater so it is not properly focused

(2) The slide could be stuck to the lens.