| Describe and Explain the Practical of Testing the Action of Antibiotics [Part 1: Explain up to when the Bacteria has Covered the Jelly] | 1. Pour Hot, Sterilised Agar Jelly into a Petri Dish [Round, Small Dish]
2. When the Jelly Cools, Inoculating Loops [Wire Loops] used to Give Microorganisms to the Culture Medium [Agar Jelly]
3. Take 3 Discs of Filter Paper, and Soak 1 in Antibiotic A, Soak another in Antibiotic B and the Last One is a Control, Soaked in Sterile Water [Useful later]
4. Place the Discs onto the Jelly via Sterile Forceps, and Tape the Lid onto the Dish to not allow Contamination from other Microbes. Antibiotics will soak into the Agar Jelly [Diffuse]
5. Leave for around 2 Days at 25 Degrees. What you will see is the Bacteria will Multiply and make a Lawn. |
| Describe and Explain the Practical of Testing the Action of Antibiotics
[Part 2: Explain from 'Lawn' of Bacteria to the End] | 6. A Clear Zone will also be Visible, meaning that the Bacteria could NOT grow there. The larger the Area of the Clear Zone; the more Effective the Antibiotic was [πr²]
7. The Control Disc will ensure that the Difference will be Evident in terms of Growth of Bacteria in the Control Disc and the Antibiotic Discs. If not then well the Paper is Weird, or another Factor is Involved [Bacteria might be Resistant to the Antibiotic]
8. Antiseptics or Antivirals also can be Used, to see how Effective they Are. |
| Why in the Practical of Testing the Action of Antibiotics is:
1. Agar Used for the First Stage?
2. The Temperature at 25 Degrees? Is it Different in Industry's? | 1. Agar Jelly is the Culture Medium - It has all the Resources like Carbohydrates and Vitamins needed for the Microorganism to Grow
2. 25 Degrees is seen at the School Experiment [Not Trinity School] because then Harmful Pathogens can't Grow really. [This means Temperature is a Variable that needs to be Controlled]
-In Industrial Usage, then the Temperature is Higher, for More Growth. Beware though that Too High means the Enzymes in the Microorganisms may Denature |
| Why may Contamination from Unwanted Microorganism Ruin the Results? How can you Ensure that this Doesn't Happen? | -Contamination will Ruin the Results because it may be Immune, or be Different to what the Antimicrobe is trying to Achieve.
1. Disinfecting the Work Area is Key, like Alcohol [That's Flammable]
2. Sterilise all Equipment and Glassware, like Forceps, Before and After Usage in a Autoclave. Agar Jelly also to be put in Autoclave
3. Inoculating Loop [Wire Loop] Sterilised by putting it through a Hot Flame [Bunsen Burner]
4. Bunsen Burner should be Near the Practical as Microbes in the Air will Rise, because Hot Air Rises, so it won't Interfere with the Practical
5. Flame the Neck of the Container of Bacteria AFTER its Opened and BEFORE its Closed so Unwanted Microbes can't Fall in |
| How can you Compare how Effective the Antibiotics was, on the Practical of Testing the Action of Antibiotics? | -Simply by Looking at their Clear Zones can give you a Idea how, Bigger = More Effective
-If its Hard to use Visual, then get the Area of the Clear Zone by using the Formula of a Circle, because the Clear Zone is a Clear Zone.
-Remember, Measure from the BOTTOM of the Petri Dish because you have Microbes that may be Dangerous. |
