Leture 6: Microbial Nutrition & Growth Flashcards
What is an increase in numbers of cells (microbes), not in cell size?
Microbial Growth
What is microbial growth?
What is an increase in numbers of cells (microbes), not in cell size?
What is an aggregation of cells arising from single parent cell?
Colony
What is a colony?
An aggregation of cells arising from single parent cell
What gives the cell the energy for reproduction (growth)?
Metabolism
What does metabolism do?
Gives the cell the energy for reproduction (growth)
What results in growth?
Reproduction
What are the physical growth reqirements?
Temperature
pH (acidic, neutral, basic/alkaline)
Water (osmotic pressure and hydrostatic pressure)
What is the temperature range for
Psychrophiles?
-5 to 20 degrees C
What is the temperature range for Mesophiles?
15 to 45 degrees C
What is the temperature range for ?
What is the temperature range for ?
Most bacteria & protozoa grow between pH 6.5 & 7.6, this is what type of pH?
Neutrophiles
Which type grow in acidic environments, that allow for molds and yeast to grow between pH5 and 6?
Acidophiles
Which type live in basic environments (soils and water) 9 to pH 11.5?
Alkalinophiles/ Alkaliphiles
When you have a high hydrogen ions, what does that mean for your pH?
Low pH and high acidity
When you have low hydrogen ions, what does that mean for your ph?
High pH and low acidity
What type of pressure exerted on a semi-permeable membrane by a solution containing solutes that cannot freely cross the membrane?
Osmotic Pressure
Where do metabolic reactions take place?
Water
Do most cells die in absence of water?
Yes
Water exerts pressure in proportion to its depth, is what?
Hydrostatic pressure
Which organisms that live under extreme pressure?
Barophiles
How do barophiles maintain their three-dimensional, functional shape?
Membranes and enzymes depend on this pressure
What type of transport requires no energy?
Passive transport
What type of transport requires energy?
Active transport
What is movement of molecules to fill available space?
Diffusion
Molecules moves randomly but diffusion may be directional
Substances diffuse down their concentration gradient (corner of smoker to in front of you is the gradient)
What does it mean to have the same amount of molecules moving across the membrane in each direction?
at equilibrium
Solute moves from an area of high concentration to an area of low concentration, no energy required.
Simple diffusion or directional net diffusion
What is the diffusion of water across a selectively permeable cell membrane?
Osmosis
This process of water diffusing across a membrane from the region of lower solute concentration to the region of higher solute concentration is of what?
Osmosis
The ability of a surrounding solution to cause a cell to gain or lose water is what?
Tonicity
What type of solution has: outside solute concentration is greater than that inside the cell?
Hypertonic
Cell is shriveled
What type of solution has: outside solute concentration is the same as the inside the cell?
Isotonic
Normal cell
What type of solution has; outside solute concentration is less than that inside the cell?
Hypotonic
Cell is lysed
The ability of an extracellular solution to make water move into or out of a cell by osmosis
Tonicity
When water moves into the cell and may cause the cell to burst if the wall is weak or damaged (osmotic lysis)
Hypotonic
When water moves out of the cell. causing its cytoplasm to shrink (plasmolysis)
Hypertonic
When there is no net movement of water
Isotonic
In animal cells when the cell’s shrink and cause death, this is?
Plasmolysis
What are chemical growth requirements?
Nutrients
What allows for energy needs, build organic molecules, and build cellular structures?
Nutrients
carbon
nitrogen
sulfur
phosphorous
trace elements
Organic chemicals that cannot be synthesized by certain organisms
Growth factors
four basic groups of organisms
Require oxygen, undergo aerobic respiration
Obligate Aerobes
Can maintain life with our without oxygen via fermentation or anaerobic respiration or by aeroobic respiration
Facultative Anaerobes
Aerobes that require lower levels of oxygen
Microaerophiles
levels from 2-10%
limited ability to detoxify hydrogen peroxide and superoxide radicals
Do not use aerobic metabolism but have some enzymes that detoxify oxygen poisonous forms; can use oxygen when present, and can also survive without oxygen
Aerotolerant anaerobes
Do not use aerobic metabolism but have some enzymes that detoxify oxygen poisonous forms. Do not use oxygen but can survive in oxygen
Aerotolerant Anaerobes
Do not use aerobic metabolism, oxygen is toxic to them, cannot live in oxygen
Obligate Anaerobes
toxic forms of oxygen
