Chapter 6 Microbiology Notes

What is a pure culture

a single strain of a species of bacteria, they are genetically identica to one another

What are 2 methods that can easily be utilized to obtain pure cultures of bacteria?

Streak method and spread plate

What is serial dilution

a procedure that can be used to enumerate bacterial cultures.

What is 1?

Lag

What is 2?

Log

What is 3?

Stationary

What is 4?

Death

Bacteria grows at what kind of rate?

Exponential

A growth medium in which there are ingredients included which are designed to exclude or stop growth of a certain type of organism

Selective growth medium

A growth medium that only has the bare minimum needed nutrients and ingredients to permit organisms to grow

Minimal growth medium

A nutrient-rich medium that specifically is created to help culture and grow organisms that are fastidious and difficult to culture on artificial growth media

Enriched growth medium

A growth medium that is designed to use ingredients and nutrients that a wide variety of microorganisms, including bacteria, yeasts, and fungi, are able to metabolize

General growth medium

A growth medium that distinguishes different biochemical abilities by microorganisms, by turning a different color which will define the characteristics of that organism

Differential growth medium

Carbon source:

Heterotroph and Autotroph

Heterotroph

Needs to consume already biologically fixed carbon sources

Autotroph

Can fix or make its own carbon source, typically from CO2

Energy source

Phototroph and Chemotroph

Phototroph

Energy source comes from light

Chemotroph

energy source comes from the consumption of chemical compoundsE

Electron source

Lithotroph and Organotroph

Lithotroph

electon source for energy comes from inorganic compounds

Organotroph

electron source for energy comes from organic compounds

If an organism gets its carbon from consuming previously fixed compounds and energy, and its electron source comes from organic chemicals, how would you classify this organism?

Chemoorganoheterotroph

First step of the nitrogen cycle

Nitrogen fixation

what is Nitrogen fixation?

Make N2 into NH4

What is the 2nd step in the nitrogen cycle?

Nitrification

What is nitrification?

NH4 is converted into NO3

What is the 3rd step of the nitrogen cycle?

Denitrification

What is Denitrification?

Nitrate is broken down into other nitrogen forms until it is back to N2 gas

the minimum or coldest the temp needs to be for the microbes to still grow

Minimal growth temperature

The temp at which the rate of reproduction is the fastest for that microbe

Optimal growth temperature

The max or the hottest the temp can be before the bacteria start to die due to the denaturing of proteins and enzymes

Maximum growth temperature

True or False: The optimal growth temperature is the ideal temperature for reproduction and all enzymatic activity in a cell

False

Why is it possible for organisms to stay alive if they are below their minimum growth temperature for a prolonged period, but tend to die very quickly when they are placed above their maximum growth temperature?

When cells are placed below their minimum, their metabolism and biological enzymes essentially freeze. Still, the shape and structure of the cells may be maintained, so when cells are brought back to their optimal range, growth may continue. When cells are placed above their maximum for too long, proteins and enzymes, and cell structures denature, and this is a permanent conformational change, and it cannot be fixed so the cell dies

Acidophile

an organism that thrives at a pH of 2-3

Neutrophile

an organism that thrives in a pH of around 7 and cannot withstand major shifts in either acidic or basic direction

Alkalophile

and organism that thrives in a pH of 10-11

Aerotolerant Anerobe

Does not utilize oxygen at all for any metabolic process, relies exclusively on fermentation to obtain energy, but is also not killed by reactive oxygen molecules

Obligate aerobe

Requires oxygen to be present in order to survive

Obligate anergobe

Requires the absence of oxygen in order to survive - O2 is toxic to these organisms

Facultative anaerobe

Grows the fastest and most abundantly with oxygen present; however, has other energy-deriving pathways that does not use oxygen, and so it can still grow with little to no oxygen present M

Microaerophile

Requires oxygen to be present, but not at atmospheric levels, too much oxygen is toxic to them, but they cannot survive in anoxic conditions either

What is the first test tube

Obligate anaerobe

What is the second test tube

Microaerophile

What is the third test tube

Obligate aerobe

what is the fourth test tube

Aerotolerant anaerobe

What is the last test tube

Facultative anerobe

What is a biofilm

A mass of bacteria that may be made up of multiple different species of bacteria that stick to and multiply on a solid surface.

When will a biofilm form

when nutrients are plentiful on a surface

What is quorum sensing?

how the biofilm communicates, they release different chemicals called autoinducers and till trigger different responses from the microbe

The thick sticky matrix that is extremely resistant to physical changes in the environment and destruction that holds a biofilm together is called

extracellular polymeric substances