MIcrobes and Growth Flashcards
Process where nutrients are acquired from the environment for metabolism and growth.
Nutrition
What are the nutrients that:
- Required in very large amounts
- Required in small quanitities for growth/reproduction
- Macronutrients
- Micronutrients
Explain the steps to Binary Fission (five steps):
- Cell elongates
- New matieral synthesized
- Chromosome replicated
- Septum forms
- Cell divided into two progeny
What are the three phases of binary fission?
- Period of growth
- Chromosome replication (partioning)
- Cytokinesis
Name these terms involved in chromosome replication:
- site where replication starts
- DNA replication machinery
- site where replication ends
- Origin of replication
- Replisome
- Terminus
Name these terms involved in Cytokinesis:
- Cytoskeletal proteins
- All proteins involved in cell division
- Formation of cross wall between two daughter cells
- Z ring
- Divisome
- Septation
Time needed for complete fission cycle:
Generation time
After each fission cycle, how much do bacteria replicate by?
By a factor of 2
What does a growth curve do?
What are its 4 phases?
Plots number of microorganisms in population over time
- Lag phase
- Log Phase
- Stationary phase
- Death phase
What is the:
- Lag phase
- Log phase
of the growth curve?
- Cells adjust to environment (not reproducing)
- Exponential growth (continues as long as nutrients available)
What is the:
- Stationary phase
- Death phase
of growth curve?
- Survival phase (replication=death rate)
- Nutrients depleted, cells die
What is a viable plate count (measurement of growth)?
A direct method that counts the number of colony forming units from media
What are microscopic counts (measurement of growth)?
A direct method of measurement where a small amount is added to a microscope with a grid
What are electron counters (measurement of growth)?
A direct method that measure culture as it passes through a detector
What is metabolic activity (measurement of growth)?
indirect method that determines the proportion of nutrients and waste production to number of microbes.
What is dry weight (measurement of growth)?
indirect method where bacteria is filtered from media, dried, and weighed
What is turbidity (measurement of growth)?
indirect method that determines how clody a tube of media becomes
more cloudy=more microbes
Explain these terms that related to Oxygen requirements:
- Obligate aerobe
- Obligate (strict) anaerobe
- Grow only in the presence of oxygen
- Die in the presence of oxygen
Explain these terms that have to do with oxygen requirements:
- Facultative anaerobe
- Aerotolerant anaerobe
- Do not require oxygen, but grow better with it
- Grow equally well with or without oxygen
What are microaerophiles (oxygen requirement)?
Require low oxygen (damaged by normal amounts
Explain these terms (environmental factors):
- halophile
- Osmophile
- Require high levels of sodium chloride to grow
- Require high levels of sugar to grow
Explain these terms (environmental factors)
- Osmotolerant
- Xerophile
- Grow optimally at high water activity
- Grow optimally at low water activity
Name these terms (Environmental factors):
- Optimal growth at 15ºC or lower
- Optimal growth between 20-30°C
- Psychrophile
- Psychrotolerant
Name these terms (environmental factors):
- optimal growth between 20-45°C
- optimal growth at 55°C or higher
- optimal growth between 85-120°C
- Mesophile
- Thermophile
- Hyperthermophile
Name these environmental factors:
- Optimal growth between pH 0-5.5
- Optimal growth between pH 5.5-8
- optimal growth between pH 8-11.5
- Acidophile
- Neutrophile
- Alkaphile
Name these environmental factors:
- increased pressure adversely affects them, but not completely
- •maximal growth is at higher pressure (> 1 atm)
- Barotolerant
- Barophilic
Name these environmental factors (radiation)
- Very short wavelengths and high energy results in mutation
Ionizing radiation
Name this environmental factor (radiaition)
Short wavelength and high energy. Results in DNA damage
UV radiation
Name this environmental factor (radiation)
Photosensitizer absorb lights, transfers energy to O2 to become singlet O2
- How do microorganisms counter this effect?
Visible light
- Carotenoids
What are biofilms?
How do they form?
Complex, slime-encased community of microbes
Form on any substrate through Extracellular Polymeric Substances
What purpose do biofilms serve?
- More resistant to antimicrobials
- Serve as reservoir for infection
What do microbes use to communicate in Biofilms?
Molecule called:
Quorum sensing
