Physical Growth Requirements (Chapter 8 + 9) Flashcards
Each microbe has a certain range of temperatures in which it will be able to -
Grow
Lowest temp at which an organism can conduct metabolism =
Minimum Growth Temp
Usually results in slow growth =
Minimum Growth Temp + Maximum Growth Temp
When temp exceeds this value, an organisms proteins become denatures and it dies =
Maximum Growth Temp
Temp at which an organism’s metabolic activities produce the highest growth rate =
Optimal Growth Temp
Microbes can be classified or distinguished from one another based on the-
Temp range at which a microbe can grow
Best below 15c. Can even grow below 0c. Die above 20c =
Psychrophiles
Algae, fungi, archaea + bacteria living in snowfields, ice, cold water =
Psychrophiles
Tolerate but don’t grow best in cold. Typically grow best from 20-25c but range is from 0-45c =
Psychrotolerants (Psychotrophs)
Listeria monocytogenes + Bacterial pathogen that grows in refrigerated food =
Psychrotrophs
Grow best between 20-40c =
Mesophiles
Most human pathogens =
37c
Grow above 45 =
Thermophiles
Grow above 80c =
Hyperthermiles
Thermophiles + Hyperthermophiles are not-
Pathogens
Psychrophiles don’t cause-
Disease
Scale or range of free H+ or free OH- ions in a solution =
pH
The more H+, the more-
Acidic
The more the OH-, the more -
Basic (Alkaline)
Below 7 =
Acidic
7 =
Neutral
Above 7 =
Basic/ Alkaline
Microbes are sensitive in changes to-
Acidity
Grow best in a neutral range around neutral pH =
Neutrophiles
Most bacteria + Most protozoa + Most Pathogens =
Neutrophiles
Neutrophiles grow between-
6.5-7.5
Grow best in acidic environments =
Acidophiles
Most bacteria + Most Fungi =
Acidophiles
Live in alkaline soils + water =
Alkaliphiles
Grow up to 11.5 =
Alkaliphiles
Vibrio Cholerae (Up to 9) =
Alkaliphile
Pressure exerted on a semi-permeable membrane by a solution containing solutes that can’t freely cross the membrane =
Osmotic Pressure
Hypotonic solutions have-
Lower solute concentrations
When a cell is placed into a hypotonic solution it -
Swells
Hypertonic solutions have -
Greater solute concentrations
When a cell is placed into a hypertonic solution it-
Shrivels
Osmotic pressure restricts organisms to-
Certain Environments
Require high salt =
Obligate Halophile
Tolerates high salt =
Facultative Halophile
Staphylococcus aureus tolerates up to what % of salt in order to colonize the skin?
20%
The Staphylococcus aureus is a -
Facultative Halophile
Protects cells from osmotic pressure =
Cell wall
Cell wall is important because it-
Protects against the transport of water
The force water exerts on the cell membrane =
Osmotic pressure
When there’s more solutes inside the cell than outside, water-
Moves into the cell and causes it to burst
When there’s more solutes inside the cell than outside, water moves into the cell in order to-
Establish equilibrium
When the cell membrane shrink and detaches itself from the cell wall =
Plasmolysis
Plasmolysis occurs in-
Hypertonic Solutions
Very salty/ sugary foods cause cells to -
Lose water
Cell shrinkage is reversible but will eventually lead to-
Cell death
What’s essential for obligate aerobes?
Oxygen
Oxygen is deadly for-
Obligate Anaerobes
Oxidation can cause irreparable damage to to certain cells like-
DNA Damage + Damage Lipids (Cell Membrane Damage)
Toxic forms of oxygen are highly reactive + excellent oxidizing agents.
True or false?
True
Obligate Aerobes are also called
Obligate Anaerobes =
= Strict Aerobes
= Strict Anaerobes
Microaerophiles require oxygen levels of-
2-10 %
Chemical processes that occur within a living organism to maintain life=
Metabolism
How can facultative anaerobes survive without oxygen being present?
By making enzymes that detoxify oxygen’s poisonous forms + being able to switch between methods of energy production
How can aerotolerant anaerobes survive with the presence of oxygen?
By making enzymes the detoxify the poisonous forms
Catabolic reaction -
Releases energy
Anabolic reaction -
Requires energy
Breaking down molecules =
Catabolic reaction
Building Molecules =
Anabolic Reaction
Substances that increase the likelihood of chemical reaction =
Catalyst
Organic Catalysts =
Emzymes
What always ends with the suffix -ase ?
Enzymes
The energy required to initiate a chemical reaction =
Enzyme
Break molecules by adding water (hydrolysis) =
Hydrolase’s
Ligands (Polymerase’s) join-
Molecules
Make their own food, photosynthetic organisms =
Autotrophs
Catabolize organic molecules acquired from other organisms =
Heterotrophs
Adenosine Triphosate (ATP) =
Energy currency in the cell
Simple sugars like glucose are great to be converted to-
ATP