Microbiology

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Why are bacteria important to organisms?
Because they decompose and recycle nutrients and can cause disease
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What are the 3 types of bacteria and what is their shape?
Bacillus (rod shaped) Cocci (spherical) Spirillum (corkscrew)
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What are cyanobacteria?
A group of bacteria that are filamentous and photosynthetic
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What are the features of Gram positive bacteria?
The colour of the cell after gram stain is purple, cell wall doesn't contain lipopolysaccharides has thicker peptidoglycan and is a less complex, cell wall retains crystal violet dye + is more susceptible to antibiotics and lysosomes
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What are the features of Gram negative bacteria?
The colour of the cell after gram stain is red, the cell wall contains lipopolysaccharides and peptidoglycan and less complex, cell wall doesn't retain dye and is not effected by enzymes + resistant to lysosomes
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Give examples of Gram positive and Gram negative bacteria?
Gram positive - Bacillus + Staphylococcus Gram negative - E.Coli + Salmonella
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How does a cross linked wall aid the cell wall?
It provides strength, gives the cell its shape and protects against swelling or bursting (lysis)
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How bacteria reproduce?
Asexually by binary fission - although some can reproduce sexually
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Describe the lag phase
The production rate is greater than the death rate, water is taken in, protein synthesis occurs to produce enzymes
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Describe the log phase
Production rate much greater than death rate, can last a few minutes or days and no limiting factors, exponential growth of population
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Describe the stationary phase
Production rate is equal to death rate, limiting factors enabled such as lack of nutrients/ predation, carrying capacity reached
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Describe the death phase
Production rate is smaller than death rate, causes decline in population, run out of nutrients or build up of toxic waste
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What are the types of anaerobes?
Obligate anaerobes - will only grow if no oxygen present, Obligate aerobes - will only grow if oxygen is present, Faculative anaerobe - will grow when no oxygen preset but grows best in presence of oxygen
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What conditions are needed for microbes to grow?
Oxygen, correct temperature, pH, source of nitrogen, source of carbon, vitamins and minerals
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How do you prevent contamination of cultures by bacteria from the environment?
Sterilise apparatus, sterilise media (agar), use correct handling techniques
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How do you prevent contamination to the environment?
Disinfect work surfaces (lysol disinfectant 3%), use correct handling techniques
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What are the correct handling techniques?
Use a Bunsen burner to create a convection current, don't put cap of culture bottle onto bench, flame mouth of culture bottle, flame inoculating loop, only open petri dish to 45', don't seal petri dish, incubate petri dish at 25'
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What is the difference between total and viable count?
Total counts are living and dead cells and viable counts are only living cells
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What is an autoclave?
A piece of heat apparatus under 121', under pressure for 15 minutes which destroys bacteria that are resistant to boiling
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What is biotechnology?
The industrial application of living organisms
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What are the advantages of using microbes in fermentation?
Reproduce quickly, organisms contain enzymes - no additional enzymes need to be added, cheaper as reaction can be carried out at a lower temp
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What is batch culture?
When microorganisms are cultures in a fermenter - all materials and nutrients are added at the start and nothing is added during the fermentation process
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What is continuous culture?
When microorganisms are cultured in a fermenter when the nutrients are added and products are harvested throughout the fermentation process
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What is a primary metabolite?
They are involved in normal growth and metabolism of cells, the production of primary metabolites match the growth rate if the population
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What is a secondary metabolite?
They reach a maximum level after the exponential growth phase - to reduce competition and kill bacteria around itself, they may also by secreted by cells
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Card 2

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What are the 3 types of bacteria and what is their shape?

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Bacillus (rod shaped) Cocci (spherical) Spirillum (corkscrew)

Card 3

Front

What are cyanobacteria?

Back

Preview of the front of card 3

Card 4

Front

What are the features of Gram positive bacteria?

Back

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Card 5

Front

What are the features of Gram negative bacteria?

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