summary pt.3

Helminths and its types

Trematodes (flatworm)

Cestodes (tapeworms)

Nematodes (roundworms)

Environmental factor influencing bacteria, Temperature: growth is influenced by cardinal temps

Minimum: lowest for growth and metabolism

Maximum: highest for growth and metabolism

Optimum: promoting fastest growth

Microbial classification by temp preference:

Psychrophiles: cold-loving (0-20C)

Mesophiles: moderate temp (20-45C)

Thermophiles: heat-loving (45-80C)

Oxygen requirements of bacteria

Obligate aerobes

Facultative anaerobes

Aerotolerant anaerobes

Capnophites

Obligate aerobes

Require oxygen to survive and grow (micrococcus)

Facultative anaerobes

Cannot tolerate oxygen (clostridium)

Aerotolerant anaerobes

Do not use oxygen but can survive in its presence

Capnophites

Prefer high CO2 concentration (Neisseria, streptococcus pneumoniae)

Toxic oxygen by products

1. singlet

2. superoxide free radicals (O2)

3. hydrogen peroxide (H2O2)

Singlet oxygen

Very reactive, produces by phagocytes to kill bacteria

Superoxide free radicals (O2)

Require dismutation by SOD to be neutralized

hydrogen peroxide (H2O2)

Toxic; neutralized by catalase or peroxide

Exponential growth: Nf

Final number of bacteria

Exponential growth: Ni

initial number of bacteria

Exponential growth: n

number of generations

Lag phase

Preparation for growth

Log phase

Exponential growth

Stationary phase

Growth rate equals death rate

Death phase

Death rate exceeds growth rate

simple enzyme

composed only of protein

conjugated enzyme

comprised of cofactor

anaerobic cellular respiration steps

1. Glycolysis

2. Fermentation

Aerobic cellular respiration steps

1. Glycolysis

2. Kerbs cycle

3. Electron transport system