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Growth and Cell Division

Growth

Budding
– Yeasts and some
bacteria

Binary fission
– No mitosis
– Unequal partitioning of
cytoplasm
– Multiple chromosomes
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Bacterial Growth Curve

Lag phase

Log phase

Stationary phase

Death phase
2
Physical Factors Affecting Bacterial
Growth

pH

Temperature
–
–
–
–
–
Psychrophiles
Psychrotrophs
Mesophiles
Thermophiles
Extreme thermophiles
3
Physical Factors Affecting Bacterial
Growth - Oxygen

Obligate aerobe

Obligate anaerobe

Microaerophile

Facultative anaerobe

Aerotolerant anaerobe
4
Physical Factors Affecting Bacterial
Growth

Hydrostatic pressure

Osmotic pressure

Radiation
5
Nutritional Factors Affecting Bacterial
Growth

Carbon source

Nitrogen source

Sulfur/ phosphorus

Trace elements

Vitamins

Nutritional complexity
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Culturing Bacteria - Streak Plates

Streak plate method
7
Culturing Bacteria - Pour Plates

Pour plate method
8
Culture Media

Types
– Defined


Purposes
Selective media

Differential media

Enrichment media

Propagation media
– Complex
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