Section: ___________________
Bacterial Morphology
Pg 61
Part 1: Viewing Prepared Slides of Common Bacterial Shapes
Familiarize yourself with each morphological type to use as a comparative tool for the remainder of the activity. Record your observations.
Part 2: Disinfecting Your Area to Use Live Organisms:
Part 3: Viewing Live Organisms – Wet Mount Preparation
Record your observations.
Part 4: Direct Staining:
Record your observations for each sample.
Part 5: Indirect Staining:
Examine the stained specimens and record your results.
Questions:
A. What are the advantages of using bleach as a disinfectant? The disadvantages? The advantages of using 70% alcohol? The disadvantages?
The advantages of using bleach as a disinfectant is strong and effective disinfectant. Its active ingredient, sodium hypochlorite, denatures protein in micro-organisms and is therefore effective in killing bacteria, fungus, and viruses. Household bleach works quickly and is widely available at a low cost. The disadvantage is could irritates mucous membranes, the skin, and the airway. It also decomposes under heat or light and reacts readily with other chemicals. Bleach solutions begin to lose its effectiveness after 2 hours. You will need to make a fresh solution for each experiment.
The advantage of the 70% alcohol mixtures is capable of killing most bacteria within 5 minutes of exposure. It is a 70% isopropyl alcohol solution suitable for use as a disinfectant and is safe for contact with the skin. Alcohol mixed with water is an effective disinfectant. The water is the mix prevents the cell from dehydrating and allows the alcohol component to disrupt the cell membrane and enter the cell resulting in the denaturing of cellular proteins. It is a 70% isopropyl alcohol for use as a disinfectant and is safe for contact with the skin.
The primary disadvantages of using 70% as