Bacterial Growth and Reproduction Notes

Bacterial growth refers to an increase in the number of bacteria, not their individual size.
Bacteria reproduce through binary fission, creating two identical daughter cells.
Generation time is the time it takes for bacteria to divide, and it varies significantly among species.
- E. coli can multiply every 10 minutes.
- Mycobacterium (tuberculosis) can take 12 hours.

Temperature:
- Psychrophiles: Prefer cold temperatures.
- Mesophiles: Prefer moderate temperatures (around 37 degrees Celsius).
- Thermophiles: Prefer high temperatures (around 65 degrees Celsius).
Water:
- Bacteria need water to reproduce; they thrive in isotonic solutions.
- Isotonic: The solution has the same concentration of solutes as inside the bacteria.
- Hypertonic solutions can cause bacteria to swell and burst due to osmosis.
Oxygen:
- Aerobes: Require oxygen.
  - Obligate aerobes: Must have oxygen (e.g., Mycobacterium tuberculosis).
- Anaerobes: Do not require oxygen; oxygen can be poisonous.
  - Obligate anaerobes: Are destroyed by oxygen (e.g., Clostridium).
- Facultative anaerobes: Can switch between aerobic and anaerobic respiration.
- Microaerophiles: require oxygen at a lower concentration.

Pili (specifically F pili) facilitate the exchange of genetic information between bacteria.
Plasmids, such as the F plasmid, can be transferred from one bacterium to another through the pilus.
This process can spread antibiotic resistance among bacteria.