Chapter Six Flashcards by Ella Thorsteinson

Determinents of growth

-temperature
-pH
-osmotic pressure
-oxygen

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Temperature has how many groups based on temperature preference

Five groups

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Psychrophile

Cold loving
-can be true loving or facilitated

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Facilitated is the same as

Psychrotrophs

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(Range of growth/optimum/found) true loving psychrophile

Range: 0 to 20/25
Optimum: 15
Found: cold regions

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(Range of growth/optimum/example) Psychrotrophs

Range: 0 to 40
Optimum: 20 to 30
Example: mold

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(Range of growth/optimum/found) mesophile

Range: 25 to 45 - 50
Optimum: 37
Example: pathogenic and extremely concerning

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(Range of growth/optimum/example) thermophiles

Range: 45 to 80
Optimum 50 to 60
Example: no health concerns to human beings

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(Range of growth/found) hyperthermophiles

Range: 100 to 110 (boiling)
Found: in the depths of ocean and a decomposing pile

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Bacteria ideal growth in pH

6.5 to 7.5

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Mold/yeast pH ideal pH level

5 to 6

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Osmotic pressure

The pressure of surrounding water- that is essential for growth and nutrients
-high osmotic pressure is dangerous for cell growth

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Isotonic

Same solute and water concentration compared to bodily fluids

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Hypertonic

High solute low water concentration

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Hypotonic

Low solute high water concentration

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Osmotic pressure is an example of

Preservatives
-salt and sugars

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Microbial life cannot survive what in osmotic pressure

Changes in osmotic pressures

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Obligate aerobes

-need O2 for growth and energy since oxygen becomes completer of ETC
-high ATP yield
Example: most bacteria

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How does obligate aerobes deal with toxic oxygen

Enzyme catalase + SOD = neutralized oxygen

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Obligate anaerobic

-does not use o2 for energy and growth as it doesn’t do ETC or KREB cycle
-absorbs only inorganic molecules
-ATP is variable

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Obligate anerobe is an example of

Any form of colistridum

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How do obligate anaerobes deal with toxic oxygen

They do not deal with it since oxygen is already harmful

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Faculatative anerobe

-can use o2 for energy and growth (inc ATP inc growth)
-doesn’t need o2 for energy and growth (will just slow ATP and growth)

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example of facultative anerobe

E coli

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How does facultative anerobe deal with oxygen toxicity

-enzyme catalase and SOD to neutralize oxygen

Aerotolarent anerobe

-tolerates o2 but prefers without (which is fermentation) -organic molecule is end result

What happens if aerotolarent anerobe is in the prescience of oxygen

Growth continues, but does not occur due to that

Example of aerotolarent anaerobe

Lactobacillus (creates lactic acid hence anerobic) -yogurt and yeast

Yeast end results and function

Co2- bread rising Ethanol - alcohol

How does aerotolarent anerobe deal with oxygen toxicity

One enzyme, SOD, allows partial neutralization -o2 is tolerate

Microaerophils

-love o2 in small quantities -need low concentration around 2 to 10 percent -are aerobic

Example of microaerophils

Helicobacter pylori (stomach or peptic ulcer) Campylobacter jejuni (gastroenteritis)

Singlet oxygen

-a toxic form of oxygen -large bodies can handle, but small bodies cannot

Singlet oxygen in small bodies can lead to

Super oxide free radicals

What is super oxide free radicals

O2 ~- Eventually leads kills cell

What neutralizes super oxide free radicals?

Super oxide dismutase

Super oxide dismutase formula

O2~- + O2~ +H —-> H2O2 + O2 -SOD is involved

What is the problem with superoxide dismutase

The cell has H2O2 -very dangerous and leads too O2(2-)

What are two ways of dealing with toxic oxygen

-enzyme catalase -enzyme peroxide

Formula for enzyme catalase

H2O2 —> H2O + O2

Enzyme peroxide formula

H2O2 + 2H —> H2O

Culture medium

Nutrients prepared for microbial growth

Sterile

No living microbes

inoculum

Introduction of microbes into medium

Culture

Microbes growing on medium -shows type of growth but not type of organism

Agar

Solidifying agent -sterilizes broth -melts and cools to solidify broth but can still be poured

Agar melts at

100 c

Agar cools at

45 c

Agar is solid at

-37c

Pure culture

Only one species/stain

Colony

Pop off cells arising from cell, spore or group of attached cells

Different types of streak plating

-selective media -differential media -selection and differentiation

Selective media

Suppress everything else -use only what you want

Example of selective media

Salmonella typhus -using bismuth sulfide agar

Differential media

Can’t select but differentiates

Examples of differential media

Streptococcus pyogenes -using blood agar

Selection and differentiation

Very rare, and suppresses unwanted microbes

Example of selection and differentiation

Staphylococcus aureus -mannitol salt agar

Salmonella typhus causes

Typhoide fever

Steptococcus pyogenes causes

Strep throat, can become GAS (invasive group A strep)

Mannitol salt agar causes

Skin infections and MRSA and TSS

binary fission

Cell elongates and divides into 2 -extremely fast

Generation time is

Always constant

What are the four phases of binary fission

-lag phase -log form -equilibrium -death

Lag phase

Is the active cells preparing for division but there is no visible growth

Log form

Exponential growth

Equilibrium

Stationary, there is no more increase of growth

death form

Logarithmic decrease

Of the four stages when are the bacteria most susceptible

During log form

during log form what are the bacteria susceptible too

-antibiotics -radiation -antiseptics