Growth and the envrionment
Figure 5.2
Figure 5-3 Psychrophilic environment and psychrophiles.
Figure 5-4 Thermophilic environments and thermophiles.
Figure 5.5
Figure 5.6
Figure 5-8 Halophilic salt flats and halophilic bacteria.
Changes in pH
Figure 5.11
Figure 5-15 A soda lake ecosystem.
Figure 5-16 Na+ circulation in alkaliphiles.
Figure 5.17
Oxygen as an Electron Acceptor
• Many microorganisms use oxygen as a terminal
electron acceptor in a process called aerobic
respiration.
Figure 5.18
Oxygen-related growth zones in a standing test
tube
Figure 5.19
• Generation and destruction of reactive oxygen
species (ROS)
Figure 5.20
Humans Influence Microbial Ecosystems
• Maximum diversity
in an ecosystem is
maintained, in part,
by the different
nutrient-gathering
profiles of
competing
microbes.
Figure 5.23
• Microbes die at a logarithmic rate.
• Decimal reduction time (D value) is the length
of time it takes an agent or a condition to kill
90% of the population.
Figure 5.25
The Phenol Coefficient
• The phenol coefficient test compares the
effectiveness of disinfectants.
Table 5.3
Figure 5.30
Antibiotics
• Antibiotics are chemical compounds synthesized by
one microbe that kill or inhibit the growth of other
microbial species.
• Penicillin mimics part of the bacterial cell wall.
•
- Prevents cell wall formation and is bactericidal
Figure 5.31
Effect of ampicillin (a penicillin derivative) on E.
coli
Figure 5.32