P19. Organuls cells

                                                            red cabadge cloroplasts (400X)

                                                                 starch granules (100X)

                                                                  starch granules (40X)

                                                                  starch granules (1000X)

                                                       orange carrot cloroplasts (400X)

                                                                         stomata (400X)

                                                                         stomata (400X)

                                                                        cheek cells (400X)

                                                                         cloroplast (100X)

(400X)

P17. Gram staining

OBJECTIVES:

• Differentiate yogurt bacteria.
• Relate the staining procedure with the structure of the cells.

MATERIAL:

• 1 Slide
• 1 Cover slip
• Tongs
• Needle
• Gram stain: crystal violet, iodine and safranin.
• Descolorize reagent: ethanol 96%
• Microscope
• Yogurt

PROCEDURE:

   1. Prepare a heat-fixed sample of the bacteria to be stained.
   2. Cover the smear with crystal violet for an exposure of 1 min.
   3. Rinse with distilled water.
   4. Apply Iodine solution for 1 min.
   5. Rinse the sample with distilled water.
   6. Decolorize using ethanol. Drop by drop until the purple stops flowing. Wash immediately with          distilled water.
   7. Cover the sample with the safrain stain for an exposure time of 45 seconds.
   8. Rinse the sample with distilled water.
   9. Gently dry the slide with paper.

CONCLUSIONS: