Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Vet Micro > Exam 2 > Flashcards

Exam 2 Flashcards

1
Q

5 phases of microbial growth curve

A
  • Lag phase
  • Exponential phase
  • Stationary phase
  • Death phase
  • Long-term stationary phase
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What happens in lag phase?

A
  • Cell synthesizing new components
  • Varies in length - in some cases can be very short or even absent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens in exponential phase?

A
  • Also called log phase
  • Rate of growth and division is constant and maximal
  • Population is most uniform in terms of chemical and physical properties
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What happens in the stationary phase?

A
  • Closed system population growth eventually ceases, totally number of viable cells remain constant
  • Active cells stop reproducing or reproductive rate is balanced by death rate
  • Population may cease to divide but remain metabolically active
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Possible reasons for stationary phase

A
  • nutrient limitation
  • Limited oxygen availability
  • Toxic waste accumulation
  • Critical population density reached
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What happens during the death phase

A
  • The cell cannot be supported and they die
  • Cells dying at a constant rate from environmental factors
  • Two alternative hypotheses: cells are viable but not culturable, or programmed cell death.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What happens during the long-term stationary phase

A
  • Continually evolves
  • Successive waves of genetically distinct variants
  • Natural selection occurs
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is culture media used for?

A

To grow, transport, and store microorganisms in lab

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Types of media

A

Defined/synthetic
Complex

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Defined/synthetic media

A
  • Each ingredient can be defined with a chemical formula
  • Use if you want to know the metabolism
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Complex media

A

Contain some ingredients of unknown chemical composition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the two types of functional media and what do they do?

A
  • Supportive or general purpose media - support the growth of many microorganisms
  • Enriched media - general purpose media supplemented with special nutrients (ex. Blood agar - adding something in tot see what it does to it)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Selective Media

A
  • Allow the growth of particular microorganisms while inhibiting the growth of others
  • Select for gram positive or negative
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Differential Media

A
  • Distinguish among different groups of microbes and even permit tentative ID phase don their biological characteristics
  • Helps identify them by what they do
  • Select for gram negative and differentiate them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Strict anaerobic microbes

A
  • lack or have very low quantities of superoxide dismutase and catalase.
  • cannot tolerate O2 and must be grown without O2.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Isolation of pure cultures

A

Allows for the study of single type of microorganism in mixed culture

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Streak plate

A
  • Technique of spreading a mixture of cells on an agar surface so individual cells are well separated.
  • Each cell can reproduce to form a separate colony.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Spread plate

A
  • Small volume of diluted mixture containing 25-250 cells
  • Spread evenly over surface with a sterile bent rod
  • Pre diluted
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Pour plate

A
  • Serially diluted
  • Mixed with liquid agar
  • Poured into sterile culture dishes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Continuous culture of microorganisms

A
  • Growth in an open system
  • continual provision of nutrients and removal of wastes.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Continuous culture of microorganisms maintains the cells in

A

Log phase at a constant biomass concentration for extended periods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What are continuous cultures used for?

A
  • Microbial growth at very low nutrient concentrations
  • Interactions of microbes under conditions resembling those in aquatic environments
  • Food and industrial microbiology
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Direct measurement of cell numbers

A
  • Counting chambers
  • Membrane filters
  • Flow cytometry
  • Electronic counters - the coulter counter
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Measurement of cell mass

A
  • Dry weight
  • Spectrophotometry
  • Concentration of a particular cell constituent (ex protein, DNA, ATP)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Most microorganisms prefer

A

Neutral environmental conditions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Extremophiles are

A

Permanently living in extreme conditions and often require the extreme condition for optimal growth

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Most common mechanisms used by extremophiles

A
  • Synthesizes specialized enzymes and proteins
  • Altering genomic material
  • Altering membrane composition
  • Opening/closing channels or similar mechanism to acquire or remove substances to balance intracellular environment
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Osmotic concentration

A
  • Outcome - there will be an influx of water in or out of the cell causing it to either shrink or burst
  • Adaptation - trigger channels in the membrane to open allowing solute to leave or increase their internal osmotic concentration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

PH

A
  • Outcome - cytoplasmic pH becomes acidic or alkalaine, cause cell death
  • Adaptation - utilize mechanisms that maintain a neutral cytoplasmic pH. - exchanging protons, synthesize specialized proteins, produce waste products to balance environmental pH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Temperature

A
  • Outcome - microbes cannot regulate their internal temperature. Enzymes do not function well outside of optimal range
  • Adaptation - utilize means to stabilize proteins and membrane.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Oxygen concentration

A
  • Outcome - orgs can be obligate (strict) or facultative (either) aerobes or anaerobes. Anaerobes utilize O2 for metabolic processes to generate energy. O2 is toxic to anaerobes and they employ other means for to generate energy.
  • Adaptation - obligate anaerobes associate with facultative anaerobes that will remove any oxygen from the environment. - Many also utilize enzymes that scavenge and neutralize reactive oxygen byproducts.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Pressure

A
  • Outcome - organisms on land and water surfaces are always at a pressure of 1 atm.
  • Adaptation - only extremophiles need adaptation mechanisms
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

How do microbes adapt to changes in osmotic concentrations?

A

Mechanosensitive (MS) channels in plasma membrane allow solutes to leave

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Halophiles

A

Grow optimally in the presence of salts at a concentrate above about 0.2 M

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Extreme halophiles

A

Require salt concentrations between 3M and 6.2M

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

PH preference in fungi

A

Most fungi prefer more acidic surroundings (ph 4-6)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Many archaea are

A

Acidophiles

38
Q

Most bacteria and protists are

A

Neutrophiles

39
Q

Ph tolerance

A
  • Using mechanisms that maintain a neutral cytoplasmic pH
  • neutrophils exchange potassium for protons
40
Q

Acidic tolerance response

A
  • Pump protons out of the cell
  • Some synthesize acid and heat shock proteins that protect proteins (cellular components)
41
Q

Many microorganisms change the pH of their habitat by

A

producing acidic or basic waste products

42
Q

High temperatures may ____ enzyme functioning and be _____

A
  • inhibit
  • Lethal
43
Q

Adaptations of thermophiles

A
  • More chaperone proteins, H binding proteins
  • More saturated, more branched and higher molecular weight lipids
  • Ether linkages (archaeal membranes)
44
Q

Barotolerant

A

adversely affected by increased pressure, but not as severely as nontolerant organisms

45
Q

Barophillic

A
  • Require or grow more rapidly in the presence of increase pressure
  • Change membrane fatty acids to adapt to high pressures
46
Q

What has the greatest impact on microbial growth?

A

Oxygen

47
Q

Microbes fall into one of three categories:

A
  • Those that use oxygen and detoxify it
  • Those that can neither use oxygen nor detoxify it
  • Those that do not use oxygen but can detoxify it
48
Q

How microbes process oxygen

A
  • Transformed into several toxic products:
    Singlet oxygen - highly reactive - can damage and destroy a cell by oxidation of membrane lipids
    Superoxide ion - highly reactive
    Hydrogen peroxide - toxic to cells - disinfectant
    Hydroxyl radical - highly reactive
49
Q

How microbes protect themselves against damage from oxygen by-products

A
  • Superoxide ion is concerted into hydrogen peroxide by superoxide dismutase
  • Hydrogen peroxide is concerted into harmless water and oxygen by catalase
50
Q

Aerobes can use ___ in their metabolism and possess the enzymes needed to process toxic products

A

Oxygen

51
Q

Facultative anaerobes do not require ____ for metabolism but use it when it is present

A

Oxygen

52
Q

Anaerobes lack the ______ _______ _______ for using oxygen in respiration

A

Metabolic enzyme systems

53
Q

Most microbial live in _____ ______ states

A

Growth arrested states

54
Q

Most microbes inhabit ______ environments

A

Oligotrophic

55
Q

Microbes have evolved many responses to starvation and environmental stress. What are they?

A
  • Morphological changes (endospore formation)
  • Enter stationary phase
  • Use cellular components as nutrients
  • Numerous genes and proteins that help
  • Viable but not culturable state
56
Q

Quorum sensing

A

Controls genes that direct activities that are beneficial when performed in synchrony.

57
Q

What is controlled by quorum sensing?

A

Bioluminescence, sporulation, competence, antibiotic formation, biofilm formation

58
Q

What does quorum sensing require?

A

An autoinducer

59
Q

Biofilm formation process

A
  1. Reversible attachment of planktonic cells
  2. First colonizers become irreversibly attached
  3. Growth and cell division
  4. Production of EPS and formation of water channels
  5. Attachment of secondary colonizers and dispersion of microbes to new sites
60
Q

Heterogeneity in biofilms

A
  • Differences in metabolic activity and locations of microbes
  • Exchanges take place metabolically, DNA uptake and communication
61
Q

Surfaces that most microbes grow attached to

A

Sessile

62
Q

Free floating

A

Planktonic

63
Q

Psychrophile

A

Cold loving
Optimal growth in 15C or less
- produce proteins and enzymes that function at low temperatures
- membrane contains more unsaturated fatty acids and genome is higher in G-C content

64
Q

Thermophile

A

Heat loving
Growth above 45C
- produces proteins and enzymes that are stable at high temperatures
- cytoplasmic membrane has more saturated fatty acids to remain stable
- utilizes gene transfer

65
Q

Acidophile

A

Acid loving
Thrive at low pH
- impermeability of cell membrane restricts the influx of protons into the cytoplasm
- reduce pore size in membrane
- specialized mechanisms prevent entry of proton into the cell and acid hydrolysis of membrane

66
Q

Alkaliphile

A

Alkaline loving
Thrive at High pH (9+)
- utilize mechanisms to acquire H+ from extracellular environment and reduce H+ leakage
- atp synthesis contributes to pH homeostasis (prevents the release of protons during the ETC)
- produce metabolic acid (increase H+ in cytoplasm)

67
Q

Xerophile

A

survive in very dry environments
- dormancy (sporulation)
- biofilm formation
- increased fatty acid content in cell meme range
- product proteins that counteract the effects of low water activity

68
Q

Osmophiles

A

Survive in environments with high osmotic pressures (sugar concentration)
- produce different alcohols and amino acids that prevent change in osmotic pressure inside the cell
- protein and enzymes have more protein charges and hydrophobicity that protects against the change in solute composition In the cytoplasm

69
Q

Piezophiles/barophiles

A

Pressures greater than 1ATM
- high pressure can cause formations of gel like membrane with decreased nutrient uptake and processing and reducing membrane fluidity
- protein structure/composition proves high flexibility, preventing conformational changes that would inhibit function
- changing membrane fatty acids to make them tolerant to pressure

70
Q

Sterilization

A

Destruction or removal of all viable organisms

71
Q

Disinfection

A

Killing, inhibition, or removal of disease causing organisms.

72
Q

Disinfectants

A

Used on inanimate objects

73
Q

Sanitization

A

reduction of microbial population to levels deemed safe (based on public health standards)

74
Q

Antisepsis

A

prevention of infection of living tissue by microorganisms

75
Q

Antiseptics

A

Applied to tissue

76
Q

Chemotherapy

A

Used of chemicals to kill or inhibit growth of microorganisms within a host tissue

77
Q

Cidal

A

Kill
Include bactericides, fungicides, and viricides

78
Q

Static

A

Inhibit growth
Include bacteriostatic and fungistatic

79
Q

Microbial control methods

A

Mechanical, physical, chemical, biological

80
Q

Mechanical methods

A

Filtration:
- Liquid - membrane filters - used in water recycling
- Air - high efficiency particulate air (HEPA) filters - used in some enclosed barns

81
Q

Physical agents

A

heat and radiation

82
Q

Moist heat (physical agent)

A
  • Autoclave - effective against all types of organisms including spores.
  • Pasteurization, boiling, steam
  • Destroys viruses, bacteria, fungi
  • Boiling will not destroy endospores and will not sterilize.
  • Degrades nucleic acids, denatures proteins, disrupts membrane
83
Q

Pasteurization (physical agent)

A

Does not sterilize but does kill pathogens and reduce bad organisms

84
Q

Dry heat (physical agent)

A
  • Less effective
  • Oxidize cells and denature proteins
  • Does not corrode glassware and metal but you have to use it at lower heat for longer time
85
Q

Ionizing radiation

A

Gamma rays

86
Q

Ultraviolet radiation

A
  • Used for water treatment
  • Creates thymine diners that prevent replication
87
Q

Chemical agents

A

Disinfectants, antiseptics, sterilization

88
Q

Disinfectants

A
  • Phenolics- denature proteins and disrupt membranes
  • Common hospital use
  • Alcohols - most widely used
  • Bacterial, spongicidal, but not sporicidal
89
Q

Antiseptics

A
  • Overuse concerns because it can select for resistant bacteria
  • Halogens (iodine) - skin antiseptic - oxidizes cell conditioners and iodinates endospores
  • Chlorine - oxidizes cell constituents and destroys vegetative bacteria and fungi - chlorine gas is sporicidal
90
Q

Sterilization

A
  • Heavy metals - effective but usually toxic
  • Quarternary ammonium compounds (detergent) - some can kill bacteria but not endospores
  • Aldehydes - Sporicidal and can be used as chemical sterilant
  • Sterilizing gas - microbial and sporicidal but DANGEROUS
91
Q

Biological agents

A

Natural control mechanisms - viral mediated lysis (release toxin into bacteria and destroys- used mostly in food)

Vet Micro (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions