7/28/2019 Biology Lab Notes

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agar

Petri plate

Biology Lab Notes

Bunsen Burning

never leave unattended when you light a Bunsen burner, the flame should be orange roll up loose sleeves and tie back long hairHow to Make an Agar Plate

1. Obtain a Petri plate and clean it.2. Use tongs to hold the Petri plate high over Bunsen burner flames while wearing goggles. Do

NOT hold the Petri plate in one place.

3. Heat both sides of the Petri plate and pour agar into it when ready.4. Leave to cool and write your names on it.

Microscopes

2 types: dissecting (40X only) and compound (up to 400X) carry with 2 hands: supporting the base and holding the arm storing microscopes:

cord wrapped around the base of the arm on low power ocular lens facing towards arm, cover on

to focus, start on low power: since good microscopes are parfocal (ie. it stays in focus when magnification is changed),

once in focus on low power you will only need fine focus on medium and high power

only usefine focus on high powerHeat Fixing Bacteria on a Slide

1. Put a drop of water on the slide.2. Use an inoculating loop to put a small amount of bacteria into the water.3. Mix them in.4. Heat the slide until the water evaporates.

Bunsen Burner

Ring Stand

Beaker*

Heating Pad

Ring Clamp

*Put agar in beaker

and loosen the cap.

1 dot = 1 colony

7/28/2019 Biology Lab Notes

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The Gram Stain

1. Add crystal violet stain (2-3 drops) on top of the bacteria. Wait 1 minute.2. Let excess liquid run off and add Grams Iodide (2-3 drops) for 1 minute.3. Rinse with water and add 2-3 drops of alcohol. Wait 30 s and rinse again with water.4. Add 2-3 drops of Safranin O. Wait 1 minute and rinse with water.

k

crosslinks

Gram +

(stained purple from

crystal violet andmade permanent

with Grams Iodide)

Gram

(stained pink

from Safranin O)

You must be able to identify the following:

Gram + or Gram Baccillus, Coccus, or Spirillum Strepto (chains), Staphylo (clusters),

or Diplo (pairs)