MT1 > Ecology of Bacteria and Viruses Flashcards

1
Q

What 2 main factors differentiate Bacteria/Archaea from Viruses?

A

Bacteria/Archaea:

  1. Are unicellular living organisms with no organelles
  2. Have a complete set of RNA (rRna, tRNA)
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2
Q

What environments can support bacterial growth?

A

Almost every environment on earth, even extreme ones.

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3
Q

What are the 6 main characteristics of bacteria (+Archaea)?

A
  1. Self-feeding
  2. Self-replicating (growth)
  3. Differentiation (sporulation)
  4. Chemical signalling (quorum sensing)
  5. Movement
  6. Evolution
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4
Q

Describe the characteristics of an autotrophic organism.

A

Derives energy from light or chemical oxidation. Derives carbon from CO2 or carbonate.

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5
Q

Describe the characteristics of a heterotrophic organism.

A

Derives energy from oxidation of organic molecules. Derives carbon from metabolic intermediates.

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6
Q

What does Liebig’s Law of the Minimum stipulate?

A

Growth is not controlled by the total amount of resources available, but by the scarcest resource (limiting factor).

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7
Q

What is a real world example of Liebig’s Law of the Minimum at work?

A

Plant growth often is not limited by water or sunlight, but rather by nitrogen or phosphate in the soil.

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8
Q

How can iron act as a limiting factor (as in Liebig’s Law of the Minimum)?

A

Iron is critical for several metalloproteins in the body, and several bacteria have evolved iron carriers to take advantage of ferric iron in the body.

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9
Q

What 2 principles constrain Liebig’s Law of the Minimum?

A
  1. Only applicable under steady-state conditions (non-transitioning ecosystem)
  2. Limiting factor may change according to interaction of environmental variables
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10
Q

What does Shelford’s Law of Tolerance stipulate?

A

Success of an organism relies not only on the availability of nutrient but also that organism’s tolerance to the environment. Optimal and minimal conditions exist.

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11
Q

What differentiates eurytypic organisms from stenotypic organisms?

A

Eury: grow within a wide range of a specific condition (ex: temp)
Steno: grow only in a narrow range of a specific condition (ex: temp)

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12
Q

What is meant by “quorum sensing”?

A

Cells reach a certain density and can start expressing proteins which can affect the surrounding population.

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13
Q

How much ferric iron is contained in the human body?

A

Only 5g!

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14
Q

What is “diauxic growth”?

A

Cell growth in 2 phases. Caused by the organism switching from one nutrient source to another more beneficial one.

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15
Q

What are 4 examples of environmental factors that might affect bacteria growth?

A
  1. Water
  2. Sodium
  3. Light
  4. Temperature
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16
Q

In what 3 main ways does temperature affect the growth and survival of organisms?

A
  1. Rate of chemical reactions
  2. Denaturation of proteins
  3. Climate
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17
Q

At what temperatures do mesophilic bacteria thrive?

A

~ 39C

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18
Q

At what temperatures do thermophilic bacteria thrive?

A

~ 60C

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19
Q

At what temperatures do hyperthermophilic bacteria thrive?

A

~88C or even greater

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20
Q

At what temperatures do psychrophilic bacteria thrive?

A

~ 4C

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21
Q

What temperature range do pathogenic bacteria usually prefer?

A

Mesophiles who prefer temperatures in a narrow range ~37C (the normal temp of the human body).

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22
Q

Describe the oxygen relationship of a bacteria which is an “obligate aerobe”.

A

Requires oxygen for aerobic respiration.

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23
Q

Describe the oxygen relationship of a bacteria which is a “facultative aerobe”.

A

Oxygen helpful, but not required. Can do aerobic or anaerobic respiration, as well as fermentation.

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24
Q

Describe the oxygen relationship of a bacteria which is a “microaerophile”.

A

Requires oxygen for aerobic respiration, but at lower than atmospheric levels.

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25
Q

Describe the oxygen relationship of a bacteria which is “aerotolerant”.

A

Oxygen has no effect. Uses fermentation for energy.

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26
Q

Describe the oxygen relationship of a bacteria which is an “obligate anaerobe”.

A

Oxygen harmful or lethal. Can do anaerobic respiration and fermentation.

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27
Q

What sorts of energy metabolisms did organisms likely use prior to the appearance of oxygen?

A

Organisms where likely chemoautotrophic or fermentative.

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28
Q

How would you define a biological population?

A

All organisms of the same species living in the same place and time.

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29
Q

How does statistics define a population?

A

“The totality of individual observations about which inferences are to be made, existing anywhere within a defined sampling area and time.”

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30
Q

What 3 strategies have prokaryotes used to adapt to higher temperatures?

A
  1. Changing hydrophobic interactions
  2. Changing hydrogen bonding
  3. Adding more salt bridges
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31
Q

What did bacteria use to create energy before there was water?

A

Sulfur.

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32
Q

What differentiates a stable population from an unstable one?

A

Stable: population does not change over time
Unstable: population fluctuates over time according to other factors

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33
Q

What are examples of tools which can be used to count cells?

A
  • Microscope (EM or light)
  • Epifluorescence
  • Petri dishes
  • Spectrophotometer
  • Quantitative PCR
34
Q

What are the 6 growth phases of a bacterial population as described by Monod’s experiments?

A
  1. Lag
  2. Acceleration
  3. Exponential
  4. Retardation
  5. Stationary
  6. Declining
35
Q

In bacteriology, which phase is used to define a microbial population?

A

The exponential phase. A population is described by its constant rate of growth rather than an actual count.

36
Q

What effects do mixing populations in natural systems have on population growth and survival?

A

Interactions can have positive, negative, or no effect on growth and survival.

37
Q

What is the definition of a biological community?

A

A system of organisms living together and linked by the effect they have on each other and their shared environment.

38
Q

Define “neutralism”.

A

Lack of interaction between two populations.

39
Q

Define “commensalism”.

A

One organism lives off the leftover nutrients of another.

40
Q

Define “synergism”.

A

Two populations both benefit from a non-obligatory relationship.

41
Q

Define “mutualism”.

A

Two populations benefit each other and depend on one another for survival.

42
Q

Define “competition”.

A

Two populations use the same limiting resource. Both are negatively affected.

43
Q

Define “amensalism”.

A

One population produces a substance toxic to competing populations, thus gaining an advantage.

44
Q

What does the competitive exclusion principle stipulate?

A

That two populations cannot occupy the same niche. One will out-compete and eliminate the other.

45
Q

Define “parasitism”.

A

One population steals nutrients from another, indirectly harming it.

46
Q

Define “predation”.

A

One population consumes members of another for energy.

47
Q

What is an example of organisms living in a mutualistic (symbiotic) relationship?

A

Cyanobacteria/algae and lichen co-exist to form lichen. Rhizobium fixes nitrogen for plants in return for nutrients.

48
Q

What is an example of a way the competitive exclusion principle has been used in epidemiology?

A

The PCV-7 vaccine was introduced in BC to out-compete streptococcus pneumoniae.

49
Q

What is an example of an organism which exhibits amensalism?

A

Penicillium produces beta-lactam which prevents the growth of nearby bacteria.

50
Q

What differentiates an ectoparasite from an endoparasite?

A

Ecto: remain outside the cells of the host
Endo: penetrate into the cells of the host

51
Q

What is the term used to describe a virus which targets bacteria?

A

A bacteriophage.

52
Q

What is an “r-strategist” organism?

A

Organisms which favour rapid reproduction and low investment in offspring. Tend to be small and have short lifespans.

53
Q

What is a “k-strategist” organism?

A

Organisms which invest heavily in offspring and favour survival. Tend to be larger and have longer lifespans.

54
Q

What kinds of biological gradients exist which can drive population succession?

A
  • Altitude
  • Depth
  • Fresh>salt water
  • etc.
55
Q

What is the definition of an ecosystem?

A

A community and its environment treated together as a functional system of a complementary relationship, and transfer/circulation of energy and matter.

56
Q

What is the smallest unit used in ecology?

A

An ecosystem.

57
Q

What are the 4 phylodynamic categories of RNA viruses?

A
  1. Short infection w/ strong cross immunity
  2. Short infection w/ partial cross immunity
  3. Infection w/ immune enhancement
  4. Persistent infection
58
Q

Who developed the Ro # for vaccinations? When?

A

Robert May and Roy Anderson in the late 80s.

59
Q

When was smallpox eradicated?

A

1980.

60
Q

What is meant by a “nosocomial disease”?

A

A disease that is transmitted at the hospital.

61
Q

What type of infectious agent is gonorrhea?

A

Bacteria.

62
Q

What type of infectious agent is streptococcus pneumonia?

A

Bacteria.

63
Q

What type of infectious agent is malaria (plasmodium falciparum)?

A

Protozoa.

64
Q

What mutation caused some people to not contract HIV when exposed? Which gene is it a part of?

A

Delta 32, in the CCR5 gene.

65
Q

What type of infectious agent is HIV?

A

Virus.

66
Q

What type of infectious agent is influenza?

A

Virus.

67
Q

What type of infectious agent is Creutzfeldt-Jakobs?

A

Prions.

68
Q

What are the 2 proteins on the influenza virus?

A
  1. Hemagluttinin

2. Neuraminidase

69
Q

Which of the 2 inlfuenza proteins is the better target for treatment?

A

Hemagluttinin.

70
Q

What is the function of Hemagluttinin in the influenza virus?

A

Attaches to salycilic acid and allows viral genome insertion.

71
Q

What is the function of Neuraminidase in the influenza virus?

A

Allows the virus to detach from the host cell.

72
Q

How did Thomas Brock advance bacterial research?

A

He showed that bacteria could grow at extremely high temperatures by analyzing colonies from geysers in Yellowstone.

73
Q

What differentiates the IPV and OPV vaccines?

A

IPV: developed by Salk, injected
OPV: developed by Sabin, oral (can lead to paralysis)

74
Q

What is the name of the iron carriers in cyanobacteria and bacteria?

A

Siderophores, which solubilize iron for transport.

75
Q

What is enterobactin?

A

A siderophore. Transports iron and attaches to receptor, allowing bacteria to uptake iron.

76
Q

Describe Martin’s experiment.

A

Dumped iron into sea water and observed rampant chlorophyll growth.

77
Q

Hemacytometer is for blood cells what _____ is for bacteria.

A

Petrof-Hauser.

78
Q

At what salinity do nonhalophilic bacteria thrive?

A

Can’t tolerate any salt.

79
Q

At what salinity do halotolerant bacteria thrive?

A

Need a little salt.

80
Q

At what salinity do halophilic bacteria thrive?

A

Like moderate levels of salt.

81
Q

At what salinity do extreme halophilic bacteria thrive?

A

Like being salty AF.

82
Q

Place the following in order of when they increase during bacterial growth: Cell numbers, DNA, RNA, Proteins.

A

First RNA increases, then proteins, then DNA, and finally cell numbers.