Physical Factors Flashcards
WHAT CAN AFFECT THE GROWTH/SURVIVAL OF BACTERIA?
NUTRITIONAL REQUIREMENTS
PHYSICAL FACTORS
BIOLOGICAL FACTORS
- Energy
- C, H, O, N, P, S
- Salts
- Trace elements
- Vitamins
NUTRITIONAL REQUIREMENTS
- Temperature
- pH
- Osmotic pressure
- Moisture
- Gas Requirements
- Radiation
PHYSICAL FACTORS
- Relationship with other microorganisms
- Competitive, mutualistic, etc
BIOLOGICAL FACTORS
For Temperature:
incubators set at -20, 37, 56 °C
For pH:
1 N NaOH and 1 N HCl
For Osmotic pressure:
Plates with 0.85%, 2.0%, 10%, 20% NaCl
For Gas Requirements:
Thioglycollate and pyrogallol and KOH
For Desiccation:
incubator and Locker
For Radiation:
UV Chamber
range of temperature where a particular microorganism can grow: minimum, optimum, maximum
CARDINAL TEMPERATURE
affects the functions enzymes, membranes, ribosomes and other cell components
Temperature
psychrophiles CARDINAL TEMPERATURE
20 °C for maximal growth, 15 °C or lower for optimal growth, and 0 °C or lower for minimum growth
mesophiles CARDINAL TEMPERATURE
20 - 45°C
thermophiles CARDINAL TEMPERATURE
above 45 ℃ (for moderate thermophiles), 65 ℃ (for extreme thermophiles) and 80 ℃ (for hyperthermophiles)
hyperthermophiles CARDINAL TEMPERATURE
80 and 110°C
affects almost all of the metabolic processes
Enzyme activity and structure can be affected
can also disrupt membrane functions
pH
movement of water through a semipermeable membrane due to a concentration gradient
Osmosis
is the minimum pressure required to stop the net movement of water
Osmotic pressure
↑solute concentration
↑osmotic pressure
survives only in physiological saline (0.85%)
Non tolerant
tolerateS high salt concentration, optimal at physiological saline
Halotolerant
requires high salt concentration to grow (1.7% to 20%)
Halophile
requires even higher salt concentration (20% to 30%)
Extreme Halophile
