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BIO233 > Microbial Growth > Flashcards

Microbial Growth Flashcards

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

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

A

ETC

25
Q

Botulism normally from

A

CANNED food

26
Q

Temperature requirements for bacteria

A

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
Q

Which category of temperature sensitive microbes affect food preservation

A

Psychotrophs: Food spoilage of refrigerated foods
Mesophiles: Most common type of microbes; common cause food spoilage and diseases

28
Q

Categories of microorganisms based on pH

A

Acidophiles
Optimum: pH 0 - pH 5.5
Neutrophiles
Optimum: pH 5.5-8
Alkalophiles
Optimum pH 8.5-11.5

29
Q

Helicobacter pylori

A

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
Q

Categories of microorganism based on affinity to salt

A

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
Q

Sterile

A

No living microbes

32
Q

Inoculum

A

: Microbes introduced into the medium

33
Q

Agar

A

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
Q

Chemically defined (synthetic) media

A

All components known and quantified (AKA minimum media)

Bacteria is provided with everything it needs exactly

35
Q

Complex/non synthetic media

A

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
Q

Functional Types of Media

A

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
Q

Biosafety levels

A

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
Q

Bacterial growth implies

A

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
Q

Generation

A

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
Q

Standard growth curve

A

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
Q

Yeast would replicate but not produce alcohol in an environment that

A

Contained oxygen

42
Q

At what stage are bacteria more vulnerable to penecillin

A

Log stage

43
Q

The main source of nutrients in nutrient agar to grow bacteria is

A

peptone and beef extract

44
Q

The reaction that is carried out by the enzyme catalase produces

A

H2O and O2

45
Q

How long does it take for the daughter cells to initiate or start the next round of replication?

A

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
Q

Put the steps of bacterial replication in the correct order, starting from a parent cell.

A

Chromosome replication
Cell elongation
Septum formation
Separation of daughter cells

47
Q

Why is there a log stage post innoculation?

A

The bacteria must adjust to the nutrient content in the new medium, synthesizing necessary amino acids, growth factors, and enzymes.

48
Q

Why do cells enter the stationary phase

A

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
Q

How does a chemostat prolong the log stage of exponential bacterial growth

A

Chemostats provide a continued source of fresh nutrients and remove wastes and dead bacterial cells.

50
Q

The most appropriate strategy for gathering data with which to plot of a bacterial growth curve.

A

Plate count

51
Q

What results when a single bacterium reproduces

A

Two genetically identical daughter cells

52
Q

Does the nuclear envolope disapear during cell division?

A

no

53
Q

What enables the copied chromosomes to separate during binary fission?

A

The chromosomes are attached to different parts of cell membrane, which elongates and thus separates the chromosomes.

54
Q

The ability of microbes to utilize N2 as a nitrogen source is called

A

Nitrogen fixation

55
Q

Instead of oxygen, __________ may utilize nitrate or sulfate as their final electron acceptors.

A

obligate anaerobes

56
Q
A

BIO233 (18 decks)

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