BY4 - Microbiology
- Created by: beth-marie2511
- Created on: 08-06-16 08:42
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- BY4 - Microbiology
- Aseptic Techniques
- Purpose
- To prevent contamination of micro-organisms onto the agar plates.
- To prevent contamination of micro-organisms from the agar plates to the environment.
- Sterilise equipment by heating it to 121 degrees for 20 minutes.
- Autoclaving
- Flame the loop in the Bunsen burner.
- Flame the spreader after dipping it in alcohol.
- Flame the neck of the tube/bottle to create an updraft.
- Also to minimise contamination.
- Disinfect bench
- Lift lid of the petri dish enough to insert the loop or spreader.
- Wash hands before and after.
- Purpose
- Conditions necessary for growth
- Essential nutrients
- Growth
- Maintenance
- Multiplication
- Supplied in a suitable medium.
- NUTRIENT MEDIUM
- Glucose = Carbon source
- Nitrogen in the form of amino acids and proteins.
- For protein synthesis
- Vitamins are needed in small amounts ( e.g. B3 or B6)
- Mineral salts (e.g. K+ or Ca+)
- Water
- NUTRIENT MEDIUM
- Environmental Variables
- Micro-organisms grow best at a specific temperature and pH
- Optimum conditions
- Temperature
- Affects enzymes
- Ranges from 1 to 5 degrees for ocean bacteria
- 70 degrees for bacteria in hot springs
- 37 degrees for bacteria living in mammals
- Optimum pH is approx. pH7 for bacteria
- Optimum temperature for bacteria grown on agar plates is 25 degrees
- Micro-organisms grow best at a specific temperature and pH
- Essential nutrients
- Aseptic Techniques
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