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BIO233 > Microbial Growth > Flashcards

Microbial Growth Flashcards

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1
Q

The FIVE Is to be followed to purify and charcterize the organism

A

Inoculate
Incubate
Isolate
Inspect
Identify

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2
Q

What is an example of a medium

A

include liquids solids, or live organism (in the case of a Virus)

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3
Q

Innoculation

A

Place sample on sterile medium (nutrients to grown but they are the only organism present)
Using sterile loop

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4
Q

Incubate

A

Proper environment for growth (temp, pH, gas (i.e. increase/decrease amount of O2))

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5
Q

Isolation

A

Result of inoculation and incubation
Further isolate culture by “subculturing” it to obtain pure cultures
If mixture is present, choose only the colony you want

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6
Q

Inspection

A

Observing macro/microscopic characteristics
Colony shape, sizes colour, stain characteristics (gram, acid fast)

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7
Q

Identification

A

Several approaches
Morphological characteristics (cell wall, cell shapeetc.)
Useful for identifying eukaryotes
Differential staining
Gram staining, acid fast staining
Biochemical tests
Determine presence of bacterial enzymes

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8
Q

Immonoligical tests

A

Using antibodies with colours to see if they react with specific bacteria for identification

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9
Q

5 chemical requirements for bacterial growth

A

Carbon
Nitrogen
Sulfur
Phosphorus
Oxygen

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10
Q

Why is carbon required for bacteria

A

Autotrophs: Use CO2 as carbon source and inorganic salts and N source (Plants and some bacteria)
Heterotrophs: Use organic carbon sources (animals, most bacteria)
Carbon compounds are source of energy

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11
Q

Why do bacteria require nitrogen

A

Used to make amino acids and proteins

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12
Q

What do bacteria use phosphorus for

A

Used in DNA, RNA, ATP, and membranes (Source is inorganic phosphate)

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13
Q

What does bacteria use sulfur for

A

Used in amino acids, vitamins

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14
Q

What is the main requirement for oxygen in microorganisms?

A

cellular respirations

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15
Q

Thioglycolate broth

A

has an attraction for O2. Binds with O2 and generates an O2 gradient
Least O2 at the bottom of a test tube, most at the top)
Without thioglycate broth, o2 distribution would be more or less uniform

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16
Q

Obligate Aerobe.

A

Organisms that need O2: Only grow near the surface when mixed with Thioglycolate broth

Obtain energy by respiration
Produce SOD and catalse

Micrococcus and corynebacterium (skin)
Pseudomonas aeruginosa (burn infection)
Bordetella pertussis (whooping cough)
Mycobacterium tuberculosis (Lung-disease tuberculosis)

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17
Q

Strict/obligate Anerobe.

A

Organisms to which O2 is toxic. Regions without O2 contain most/all of the growth in Thioglycolate broth

Do not produce either SOD Or Catalase
Mostly carry out fermentation

Clostidium (tetani, botulinum, difficile)
Bacteroides (normal intestinal flora) - associated with APPENDICITIS

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18
Q

Facultative Aenerobe

A

Organisms that PREFER O2. Most growth near top, but growth is also spread thinly throughout the tube when in Thioglycolate broth

Produce SOD and catalse
Can carry out respiration (+O2) and fermentation (without O2)
Ex.
E. coli, Salmonella, and shigella
Staphylococcus
Saccharaomyces

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19
Q

Aerotolerant Anaerobe.

A

Organisms that ignore O2. Uniform growth, unaffected by presence of O2.

Do not require O2, and unaffected by it
Produce SOD and SOME produce catalase
Ex.
Lactobacillus and streptococcus
Sugars - lactic acid baceria
Lactobacillus
Important in women healhtm agriculture food industry
Streptococcus
Streptoccusccus pyogenes: Sore throat, scarlet fever, tonsillitis

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20
Q

Microaerophile.

A

Require less O2. Prefer to have SOME O2, but not the level that is present in air.

Require higher Co2 and lower O2 concentrations of air
Produce SOD and Catalse (Lower amounts)
Ex.
Neisseria (pathogenic/non pathogenic)
Neiseria gonorrhea (STD)
Neisseria meningitis

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21
Q

Free radicals

A

Unstable, reactive electrons released from Oxygen. damage cells cause cancer.

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22
Q

Antioxidants

A

Contain chemicals that quickly react with free radicals before they start damaging body cells

Superoxcide radical - converted to Hydrogen peroxide by superoxide dismutase (SOD) (enzyme)
Enzyme produces cataalysts that converts hydrogen peroxide to water and oxyge

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23
Q

Peroxidase

Study These Flashcards
A

Enzyme that works on hydrogen peroxide to convert it to water (Normalluy present in plants)

24
Q

Free radicals are commonly the product of

25
Botulism normally from
CANNED food
26
Temperature requirements for bacteria
Psychorphiles -10, 15C (Optimal) to 20 C Psychotrophs 0C, 25C (Opt) to 30C Mesophiles 15C (20-40C) to 45 C Most common in humans Thermophiles 45C (55-70C) to 80C Hyperthemophjils 65C, (85-95C) to 105C
27
Which category of temperature sensitive microbes affect food preservation
Psychotrophs: Food spoilage of refrigerated foods Mesophiles: Most common type of microbes; common cause food spoilage and diseases
28
Categories of microorganisms based on pH
Acidophiles Optimum: pH 0 - pH 5.5 Neutrophiles Optimum: pH 5.5-8 Alkalophiles Optimum pH 8.5-11.5
29
Helicobacter pylori
lives in stomach under mucous layer, produces ammonia to neutralize the acid of the stomach Damages mucous layer resulting in ulcers Can lead to cancer
30
Categories of microorganism based on affinity to salt
Halophiles (salt): Love high salt concentrations Non-halophiles: Prefer lower salt concentration Facultative halophiles: Prefer low salt environment, but CAN grow in high salt concentrations Extreme/obligate halophiles: REQUIRE high salt concentrations
31
Sterile
No living microbes
32
Inoculum
: Microbes introduced into the medium
33
Agar
Complex polysachharide Used as solidifying agent for culture media in petri plates, slants, and deeps Generally not metabolized by microbes Liquifies at 100 degrees C Solidifies at around 40 degrees C
34
Chemically defined (synthetic) media
All components known and quantified (AKA minimum media) Bacteria is provided with everything it needs exactly
35
Complex/non synthetic media
Some components are not known o quantified I.e. nutrient agar or nutrient broth Don’t know EXACT composition, but you know that it is providing the bacteria with what it needs
36
Functional Types of Media
Enriched media: Add some nutrients that favior growth of select bacteria (i.e. add blood, agar or choclate ) To vbe added when bacteria are resistant to growth as an extra motivating factor Differential: Distinguishes bacteria growing One process that tells the bacteria apart Selective: Encourages growth of some bacteria while suppressing growth of unwanted bacteria (Something is added to prevent the growth of something)
37
Biosafety levels
Biosafetly level 1 (Low individual and community risk) Microorganisms that handle in a basic microbiology teaching lab Non pathogenic E. coli BSL 2 (Moderate individual risk, low community risk) Microorganism that present a moderate risk of infection, operators sould wear gloves, lab coats etc. C. diff, MRSA, Salmonella BSL3 (High individual risk, low to moderate community risk) Microorganisms are highly infectious airborne pathogens Lab to be NEGATIVELY pressurized and equipped with air filters to prevent release of pathogens Mycobacterium tb, SARS coronavirus Not anyone can come in BSL4 (High individual risk, high community risk) Microorganism are highly infectious airborne pathogen No known cure Ebola virus, Lassa virus, smallpox
38
Bacterial growth implies
Increase in number of cells, not cell size One cell becomes colony of millions Bacteria divide via binary fission Alternatively divide by budding, condiospores, or fragmentation
39
Generation
the time it takes for one cell to divide can also be defined as the length of time required for a population to double
40
Standard growth curve
Lag phase: Making new enzyumes in response to new medium Log phase (exponential growth): Most sensitive to drugs and radiation during this period Stationary phase: Nutrients becoming limiting or waste products becoming toxic; death rate = division rate Death phase: Death rate exceeds division
41
Yeast would replicate but not produce alcohol in an environment that
Contained oxygen
42
At what stage are bacteria more vulnerable to penecillin
Log stage
43
The main source of nutrients in nutrient agar to grow bacteria is
peptone and beef extract
44
The reaction that is carried out by the enzyme catalase produces
H2O and O2
45
How long does it take for the daughter cells to initiate or start the next round of replication?
No time is required -- they are ready to divide immediately after DNA replication and separation of the daughter cells is complete if conditions are right.
46
Put the steps of bacterial replication in the correct order, starting from a parent cell.
Chromosome replication Cell elongation Septum formation Separation of daughter cells
47
Why is there a log stage post innoculation?
The bacteria must adjust to the nutrient content in the new medium, synthesizing necessary amino acids, growth factors, and enzymes.
48
Why do cells enter the stationary phase
The cells are likely running out of nutrients. The number of cells that are dying is balanced by the number of new cells that are being formed. Harmful waste products may be accumulating.
49
How does a chemostat prolong the log stage of exponential bacterial growth
Chemostats provide a continued source of fresh nutrients and remove wastes and dead bacterial cells.
50
The most appropriate strategy for gathering data with which to plot of a bacterial growth curve.
Plate count
51
What results when a single bacterium reproduces
Two genetically identical daughter cells
52
Does the nuclear envolope disapear during cell division?
no
53
What enables the copied chromosomes to separate during binary fission?
The chromosomes are attached to different parts of cell membrane, which elongates and thus separates the chromosomes.
54
The ability of microbes to utilize N2 as a nitrogen source is called
Nitrogen fixation
55
Instead of oxygen, __________ may utilize nitrate or sulfate as their final electron acceptors.
obligate anaerobes
56

BIO233 (18 decks)

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