Microbial Nutrition and Growth Flashcards
Essential Nutrients
any substance or nutrient the microbe must have
Two categories of Essential Nutrients
Macronutrients and Micronutrients
Macronutrients; Carbon, Hydrogen, O2
Needed in large quantities and play a huge role in cell structure and metabolism
Micronutrients or Trace Elements; Manganese, zinc, nickel
Needed in smaller quantities and play a role in enzyme function and maintaining protein structure
Categorize nutrients basses on the carbon content
Organic molecule
Inorganic molecule
Inorganic molecule
is an atom or simple molecule that does not have carbon and hydrogen in them
Organic molecule
contain carbon and hydrogen in them and are products of living things
Example of Organic molecule `
simplest organic molecules to large polymers
Example of Inorganic molecule
metals and their salts, gasses, and water
Nutrition for microbes
Carbon and energy
Organisms that use carbon source
Heterotroph- organic
Autotroph- C02
Organisms that use an energy source
phototroph- from the sun
chemotroph- from chemical compounds
Photoautotroph
Sun and C02
Photohetrotrophs
Sun and an organic compound
Chemoheterotroph definition
Metabolic conversion of nutrients and organic compounds
2 types of chemoautotrophs
chemoorganic autotrophs
lithoautotrophs
Chemoorganic autotrophs
use organic compounds for energy and inorganic compounds for carbon source
Lithoautotrophs
do not need the sun or organic nutrients only need inorganic material
Chemoheterotrophic microorganisms
Saprobes
parasites
Saprobes
feed on organic detritus from dead organisms
Parasites
feed from the cells or tissues of live host
Majority of microbes causing human disease
chemoheterotroph
Essential nutrients
Carbon, hydrogen, oxygen, nitrogen, phosphate, sulfur.
CHONPS
Environmental factors that influence microbes
temperature, pH, radiation, oxygen, osmotic pressure, hydrostatic pressure
cardinal temperature define and the three ranges
range of temperature for the growth of a given microbe.
Minimum temp
Maximum temp
Optimum temp
Minimum temp
the lowest temp that allows the growth and metabolism of microbes.
Growth is slow and if the temperature falls below temp everything stops
Maximum temp
the highest temp that allows growth and metabolism of microbe
if the temp goes higher the growth will stop and if it goes any higher enzymes and nucleic acid denature
Optimum temp
is temp between minimum and maximum and promotes the faster growth rate and metabolism
Psychrophiles
optimum temp is below 15 C and can grow at 0 C
cannot grow above 20 C
rare to be a danger to humans
Extreme psychrotrophs
grow slowly in the cold
optimum growth is 15 to 30 C
causes foodborne illness
Mesophiles
important in the medical field cause it can harm humans
optimum is 20 to 40 C
Human pathogens optima are 30 to 40 C
Staphylococcus aureus
Listeria monocytogenes
- can grow optimally in body temp but also can survive and multiply in cold temp
- will grow in temp as low as 1 C and 30 to 40 C. Grows in ice cream
Thermoduric
EX. are heat resistant endospore formers Bacillus and Clostridium
type of mesophile that can survive short exposure to high temps
contaminants heated or pasteurized foods
Thermophile
Optimum temp is greater than 45 C
range 45 to 80 C
Extreme Thermophile
can withstand sterilization
optimum is 80 to 121 C
Aerobes(obligate)
fungi, bacteria, protozoa
uses O2 for growth and can process toxic by-products
Microaerophiles
needs small amounts of O2; regular levels of O2 harm them
Facultative anaerobe
will grow with or without O2
if O2 is present in high amounts in a certain area microbe will grow more there
Anaerobe
will not grow in the presence of 02
unable to process toxic by-products of O2
Aerotolerant anaerobe
do not use 02 but can survive in O2
O2 presence will not enhance growth
Canpnophiles
grow best in high levels of CO2
Acidophiles(obligate)
live and grow in an acidic environment
pH 6 or lower
Alkaliphiles
live and grow in a base environment
Optimum pH range for microbes
pH 6 to 8
Osmophiles
live in high solute concentrations
Halophiles
Type of osmophiles that love high levels of salt
Obligate Halophiles
Need at least 9 % of salt to grow
9% to 25% is optimum
Facultative halophiles
very resistant to salt even though they do not reside in high salt areas
Barophiles
live under pressures that range over 1000x regular pressure
Symbiosis
2 organisms living together in close partnership
Three types of symbiosis
Mutualisms
Commensalism
Parasitism
Mutualism
when both parties benefit and no harm is done
Commensalism
When the organism benefits but the host is not benefited or harmed
Parasitism
the organism feeds off the host and the host is harmed and not benefitted
Biofilms
communities of bacteria or other microbes that are attached to a surface and each other
What is a ‘pioneer’ colonizer
is the first bacteria/microbe to attach to s surface
Quorum sensing
interacting with other members of the same species and other species close by to monitor the size of the population
Binary Fission
how most bacteria grow from one cell to two
Steps of binary fission
- parent cell enlarges 2. chromosomes duplicate and move to different sides 3. cell envelope pulls into the center of the cell 4. cell wall forms a complete spetum
- now the cell divides into two daughter cells
Generation/doubling time
the time needed for a complete fission cycle, from one parent cell to two daughter cells
Generation
the period between an individuals birth and the time it produces offspring
Average generation time
Shortest generation time
30-60 min
10-12 min
Growth curve
a predictable pattern of bacterial population growth in a closed system
used to observe the population growth pattern
Stages of the growth curve
Lag phase- we do not see microbial growth but cells are metabolically alive
Log/exponential phase- microbe will go through binary fission and microbe is less resistant to anti-microbial agents
Stationary phase- cells begin to die off caused by decreased nutrients, changes in pH
Death phase- more cells are dying than being created
