Study Guide Chapter 6 Flashcards
Define Bacterial growth
-Orderly increase of all the components of cells (mass/size)
- Increases in number of cells
Define generation or doubling time.
how long it takes 1 cell to divide into two cells
-Explain the process of binary fission.
Process by which bacterial cells divide
elongates, constricts, crosswall and then splits
Describe the four phases of bacterial growth and identify each on a logarithm scale graph.
- Log: rapidly growing in size (mass)
- Lag: lots of divison happening, rapidly growing (pop size)
- Stationary: equilibrium
- Death: start dying, population decreases
Differentiate between acidophiles, neutrophiles and alkaliphiles bacteria
Acidophiles: tolerant to acidic environments (less then 7)
Neutrophiles: grows best at nutural pH (6.5-7.5)
Alkaliphiles: grows best at basic pH
List and describe the physical factors that may affect bacterial growth.
- Temp: each have a temp they grow best at
-pH: each have. apH they grow best at (optimal pH)
Hydrostatic and osmotic pressure
Differentiate between vegetative cell and endospore and describe the processes of sporulation and germination
Vegetative Cell: metabolically active and capable of cell division
Endospore: small dehyddrated, metabolically inactive, highly resistant, produced when nutrients are depleated and envrionmental challenges are present
Sporulation: Asymitrically endospore formation
Germination: endospore returns to vegetative state when environment is favorable again
Differentiate between psychrophiles, mesophiles, and themophile.
Psychrophiles: cold-loving grows best at 10-20C
Mesophiles: moderate temp loving grow at 10-45C Best at 37C
Themophile: heat loving grows best at 60C
List and describe the chemical factors that may affect bacterial growth.
- Nutritional Requirements:
carbon, nitrogen, sulfer, phosphorus, trace elements, orgsnic growth factord
-Oxygen Requirements:
obligate aerobe, facultative anaerobe, anaerobes, microaerophilic, and capnophilic bacter
Explain how and why the pH of culture media is controlled.
Buffers: prevents changes to pH
Describe the different ways in which anaerobic bacteria can be cultured in lab.
Reducing broth media: contais chemicals that deplete O2
candle jars: Fire eats O2 and provides CO2
Gas Pak Chamber: O2 removed by chemical reactions
Differentiate between obligate (strict) aerobe, obligate (strict) anaerobe, facultative anaerobe, aerotolerant anaerobe, microaerophilic, and capnophilic bacteria.
Obligate (strict) aerobe: requires O2
Obligate (strict) anaerobe: inhibited or killed by O2
Facultative anaerobe: can grown with or without O2
Aerotolerant anaerobe: tolerates O2 but cant use it
Microaerophilic: likes a little air
Capnophilic bacteria: requires low O2 but rich in CO2
Identify ways in which aerobes avoid damage by toxic forms of oxygen.
Singlet O2, Superoxide Free Radicals, Hydroxyl radicals
Differentiate between halophiles and barophiles.
Halophiles: salt tolerant bacteria that can withstand high osmotic pressure
Barophiles: can withstand very high hydrostatic pressure
Define what culture media is
nutrients prepared to support microbial growth
