Microbial Growth Control
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What happens when we change pH, temperature, water activity and oxygen levels when growing microbes? Uhhhh... good question! Start studying this set to find out!
65 Terms
Law of minimum
The minimum rate an organism can grow at under any condition
Optimum
The maximum amount of growth
Law of maximum
The maximum rate an organism can grow at under any condition
pH measures…
The amount of free protons (H+) or free hydroxol groups (OH-)
A pH of 7 is…
neutral
A pH of below 7 is…
acidic
A pH of above 7 is…
basic
Some organisms can synthesize a structure under certain conditions to keep a near neutral pH in the cytoplasm. What structure is it?
Proton pump
An organism is considered an acidophile when…
their optimal growth is at, or lower than 6
An organism is considered an neutrophile when… (Optimum pH)
their optimal growth is between 6 and 8
An organism is considered an alkalophile when…
their optimal growth is at, or greater than 8
Lactococcus lactis is a(n)… (Optimum pH)
Neutrophile
Escherichia coli is a(n)… (Optimum pH)
Neutrophile
Stapylococcus aureus is a(n)… (Optimum pH)
Neutrophile
Alcaligenes faecalis is a(n)… (Optimum pH)
Alkalophile
Organisms that adapted to high temperatures have what cell membrane structure characteristic?
a lipid monolayer
Organisms that adapted to grow at high temperatures have a certain protein embedded within its cell membrane.
Heat shock proteins
The orange streamers running away from the Grand Prismatic Spring have what inside?
Microbial growth
Organisms that adapted to high temperatures have what cell membrane structure characteristic?
More unsaturated fatty acids to saturated fatty acids
Why do organisms that grow in lower temperatures have more unsaturated fatty acids in their cell membrane?
To maintain fluidity in the cell
Organisms that adapted to grow at lower temperatures have a certain protein embedded within its cell membrane.
Cold shock proteins
Microbes in icebergs generate little amounts of heat to surround itself with what?
Water
A microbe is considered a psychrophile when…
optimal growth occurs between -5 degrees Celsius and 20 degrees Celsius
A microbe is considered a mesophile…
optimal growth occurs between 20 degrees Celsius and 50 degrees Celsius
A microbe is considered a psychrotroph when…
it can survive and grow slowly at refrigeration at 4 degrees Celsius
A microbe is considered a thermophile when…
optimal growth occurs between 50 degrees Celsius and 80 degrees Celsius
A microbe is considered a hyperthermophile when…
optimal growth occurs above 80 degrees Celsius
Bacillus stearothermophilus is a… (Optimum Temperature)
thermophile
Micrococcus luteus is a… (Optimum Temperature)
mesophile
Leuconostoc mesenteroides is a… (Optimum Temperature)
mesophile
Escherichia coli is a… (Optimum Temperature)
mesophile
How can altering water activity in the cell impact growth and survival?
Creates a greater osmotic pressure within the cell
When there is high osmotic pressure inside a cell, what occurs?
Cell ruptures
When there is high osmotic pressure outside a cell, what occurs?
Cell shrinks
What are two things that can be changed to affect water activity?
Sugar and salt
After increasing the sugar concentration in water, what occurs?
Decrease in water activity, and an increase in osmotic pressure
After increasing the salt concentration in water, what occurs?
Decrease in water activity, and an increase in osmotic pressure
Bacteria that experience optimal growth in very dry environments are known as…
Xerophiles
Where might you find an xerophile?
Desert soil
Bacteria that experience optimal growth in higher osmotic pressures through high sugar concentrations are known as…
Osmophiles
Where might you find an osmophile?
Jams, jellies, and syrups
Bacteria that experience optimal growth in the presence of salt are known as…
Halophiles
Where might you find a halophile?
Salt flats and the Dead Sea
Bacteria that experience optimal growth in the absence of salt (but can still grow with some salt) are known as…
Halotolerant
Where might you find a halotolerant?
Skin that perspires
What type of bacteria can grow in the presence of O2?
Obligate aerobe
How do obligate aerobes undergo aerobic respiration?
Terminal electron acceptor
What type of bacteria require O2 for aerobic respiration but remain inactivated until O2 concentration is reduced to 2-10%?
Microaerophile
What type of bacteria cannot grow in the presence of O2?
Obligate anaerobe
Obligate anaerobes go through anaerobic respiration?
Using an inorganic terminal electron acceptor
Bacteria that prefer O2 for aerobic respiration are known as…
Facultative anaerobe
If no O2 is present, what will a facultative anaerobe do?
Perform anaerobic respiration or fermentation
Bacteria that cannot use O2 and therefore cannot go through aerobic respiration are known as…
Facultative aerobe
Facultative aerobe are also known as…
obligate fermentors / aerotolerant
What environment does a candle jar create?
Low O2 and high CO2 environment
In a candle jar, the flame extinguishes because of…
The decrease of O2 in the jar
In a candle jar, what happens to the O2 levels as the flame continues to burn?
The O2 levels become low
A candle jar promotes the growth of
Capnophiles
What environment does a Gas-Pak jar create?
Oxygen free environment
In a Gas-Pak jar’s cover, it has a basket full of…
palladium pellets
In a Gas-Pak jar, what do palladium pellets attract?
H+
The reaction of a Gas-Pac jar takes 30 years. To speed up the reaction, what is placed inside the jar?
Catalyst pack
When the catalyst pack is opened and placed into the Gas-Pak jar, what is released?
H2 and CO2
In a Gas-Pak jar, the palladium pellets convert H+ via a reaction. Write/identify this reaction.
2 H2 + O2 → H2O
A Gas-Pak jar promotes the growth of
Anaerobes