6.11 Microbial Techniques

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What does culturing microbes entail?
Providing optimum conditions such as nutrients, oxygen levels, pH levels,temperatures so that microbes can be grown in enormous amounts for reliable and valid observation and measurement
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Three reasons to take care while culturing
Risk of developing mutant pathogenic strain, risk of contamination of culture by pathogenic microbes from environment and the experimenter's body (i.e. skin)
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Health and Safety precaution while culturing, handling and disposal (2)
Use of sterile equipments before the start of experiment; Disposal via sealing in plastic bag and sterilising at 121 C for 15 mins under high pressure
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Any ethical issues?
~not really, but the risk of infecting others should be considered
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Examples of nutrients? (4 types and examples)
source of Nitrogen(NH3, NO2); source of carbon(CO2, organic substances) ;minerals (K, Ca, Fe,) ; source of protein ( blood/yeast extract/meat extract)
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Nutrient broth? ( include the way of preparation)
Nutrients in liquid form...prepared in flasks or test tubes
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Nutrient agar?( include the way of preparation)
Nutrients stored in solid form - contained in agar jelly(extracted from sea weed);
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Advantages of nutrient agar?
Agar maintains the temperature at around 50 degree Celcius ( optimum temperature) and it resists melting upto 90 degree celcius
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Define selective medium
Very specific nutrients containing growth medium for very specific microbes ( only specific microbes grow in that)
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Example of selective media
Yeast malt agar- its low pH favours fungi & moulds but not bacteria ; McConkey agar favours gram negative bacteria
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Advantage of selective media(2)
1) identify specific mutant strains of microbes and antibiotic resistance ; 2) identify genetically modified microbes
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why would selective media be helpful in identifying GM microbes?
This is because the antibiotic resistance or requirement for specific nutrient is engineered along with a desired gene as a marker
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The basic steps
1) Decide the type of micro-organism to grow ; 2) Set up the proper selective media ( sterile nutrients); 3) Perform inoculation ;4) Incubate the petridish/ flask at specific temperature for specific time;6) observation and measurement ;7) Disposal
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Other cards in this set

Card 2

Front

Three reasons to take care while culturing

Back

Risk of developing mutant pathogenic strain, risk of contamination of culture by pathogenic microbes from environment and the experimenter's body (i.e. skin)

Card 3

Front

Health and Safety precaution while culturing, handling and disposal (2)

Back

Preview of the front of card 3

Card 4

Front

Any ethical issues?

Back

Preview of the front of card 4

Card 5

Front

Examples of nutrients? (4 types and examples)

Back

Preview of the front of card 5
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