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Cell biology > Lecture 2 - Prokaryotic Cell Diversity > Flashcards

Lecture 2 - Prokaryotic Cell Diversity Flashcards

1
Q

What are the steps for Gram-Staining bacteria

A
  1. Apply crystal violet - purple dye
  2. Application of iodine - mordant
  3. Alcohol wash - (decolorisation)
  4. Application of safrarin (counterstain)
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2
Q

What colour does Gram+ look

A

Cells look purple

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3
Q

What structure do gram positive have?

A

Homogeneous

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4
Q

What is the cell wall made of?

A

Peptidoglycan

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5
Q

Gram positive bacteria contain Teichoic Acids, what is a Teichoic Acid?

A

Part of the cell wall, allow a role in pathogenesis by promoting adherence to host tissues.

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6
Q

Describe the cell wall of a Gram Negative bacteria

A
  1. More complex, thin layer of peptidoglycan is like 5-10% of the wall mass
  2. it is overlaid by a lipid layer similar to plasma membrane
  3. I don’t think it contains Teicohic acids
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7
Q

[bonus] how are the names of bacteria determined

A
  1. referred by genus which is followed by the species either in italics or underlined
  2. name often gives clues to shape, habitat or disease that is caused.

example: streptococcus pneumonia is a coccus that grows in chains bacteria causing pneumonia

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8
Q

What is the structure of Prokaryotes [6]

A
  1. coccus or sphere
  2. Rod (bacillus) may be long and thin or short and almost spherical
  3. Spiral - Curved Rod
  4. Filamentous - Actinomyctes [fiborus]
  5. May contain endospores (a resistant asexual spore that develops inside some bacteria cells)
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9
Q

What are some of the Microbial Diversity? [7]

A
  1. Encapsulated Cocous
  2. Rod shaped bacterium
    3 Filamentous Iron
  3. E.coli
  4. Gram- Negative Oxygenic
  5. Spirulina Pacifica
  6. Coltridium tetani
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10
Q

An example of an Encapsulated Coccus is Streptococcus pneumonia what are some features of it?
[2]

A
  1. Gram Positive
  2. Causes lower (pneumonia) upper infection
    (sinusitis) Causes middle infection
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11
Q

An example of a Rod bacterium is _y.enteroclitica _ what are some features of it?
[2]

A
  1. Gram negative

2. Toxin causes enteritis with appendicitis like pain

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12
Q

An example of a Rod bacterium is _VIBRIO CHOLERAE what are some features of it?
[2]

A
  1. Gram negative
  2. Curved Rod
  3. Causes asiatic Cholera
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13
Q

What is Filamentous iron? [3]

A
  1. Oxidising bacterium
  2. Form dense ropes like threads that grow in fresh water on the surface of submerged rocks
  3. Delicate threads are golden brown in colour
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14
Q

What are features of E.coli? [3]

A
  1. Gram negative with multiple flagella and frimbriae
  2. Causes UTIs and diarrhoea
  3. Important nosocomial infection (hospital acquired_
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15
Q

What is an example of a Gram Negative Oxygenic?

A

Photosynthetic Filamentous Cyanobacterium

1. Larger cells in the filaments called heterocyst which are involved in nitrogen fixation

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16
Q

What is Spirulina Pacifica? [4]

A

Gram negative
Oxygenic
Photosythentic
Filamentous Cyanobacterium

17
Q

what is cyanobacterium

A

a division of microorganisms that are related to the bacteria but are capable of photosynthesis

18
Q

What is Coltridium Tetani?

A
  1. Gram negative
  2. Rod Vegetative and spore stages
  3. Flagella and endosopres
  4. Causes Tetanus
19
Q

What adaptive features do prokaryotic cells have?

A
  1. Can tolerate vast ph, oxygen concentration and temperature ranges
20
Q

Why are cells that can exist in extreme environment of commercial interest?

A

Enzymes can be used in products such as antifreeze, washing powders, pollution decontaminants.

21
Q

What are acidophiles and what are the features of them. [4]

A

Can thrive under highly acidic conditions

  1. Can grow at pH 3 or lower
  2. Need to maintain a net outflow of protons to maintain internal pH
22
Q

[Case Study] - Thiobacillus

A

Acidophile that produces sulphuric acid by oxidation of reduced sulphur compounds
Problems:
1. Mine drainage feeds into Rio Tinto River
2.Causes a lot of pollution.

Benefits

  1. Used to leach metals from low grade ores
  2. This is important as certain metals such as copper become more expensive
  3. Low grade ores are available but not economic to smelt in usual way
23
Q

What are Alkalophiles? [3]

A
  1. Tolerant of pH above 10 and cannot grow below 8.5
  2. Must maintain a net inflow of protons to preserve internal pH
  3. Found in a number of genera notably Bacillus
    example: VIBRIO CHOLERAE
24
Q

Something unique of Alkaphiles or phobes is that there internal pH levels are neutral. [more info]

A
  1. Death occurs if internal pH falls below 5.0-5.5
  2. Potassium and sodium exchange system allows some adjutments
  3. Proton translocating ATPase also involved
25
Q

What are Aerobes? [4]

A

depend on molecular
oxygen

  1. Found in in-terrestrial and aquatic habitats where oxygen is available
  2. Often do not grow well in static cultures - low o2
  3. Cultures frequently require shaking mechanically during incubation for growth in vitro
26
Q

what are facultative anaerobes? [3]

A

use oxygen if available

  1. Many commonly used and medically significant bacteria e.g. e.coli
    Anaerobic growth requires fermentable sugar
27
Q

what are anaerobes? [4]

A

cannot use oxygen, some may be killed by them

  1. Those killed by oxygen are known as obligate anaerobes
  2. Other tolerate oxygen but do not use it [aerotolerant or aeroduric]
  3. Ability of anaerobes to tolerate depends on superoxide dismutase
28
Q

Why is SOD important? [Superoxide dismutase]

A
  1. Destroys the very toxic superoxide radical formed during oxidation of flavoproteins under aerobic conditions
  2. SOD converts superoxide radical hydrogen peroxide and oxygen
29
Q

What happens to Bacteria that lack SOD?

A
  1. Strict anaerobes die on exposure to evil low concentrations of o2
  2. Apparently due to accumulating superoxide
  3. Inhabit environment where oxygen is absent e.g. anaerobic mud
  4. May survive in strongly reducing environment
30
Q

What are the 5 different types temperaturephiles?

A
  1. Psychorophiles
  2. Psychotrops
  3. Mesophiles
  4. Thermophiles
  5. Hyperthermophiles
31
Q

What are Psychorophiles?

A
  1. Grow well at 0
  2. Optimum of 15
  3. Maxlife is 20

a. found in artic habitats and in oceans (90% of ocean is 5c or less)
b. membrane high in unsaturated fatty acids which is fluid at low temperature
c. may leak at 20 or above due to distruption

32
Q

What are Psychotrops

A
  1. Grow well at 0
  2. Optimum of 20-30
  3. Maxlife of 35

a. present in environmental in spoil on vegetarian
b. Significant cause of food spoilage, grow at refrigeration temperature.

33
Q

What are mesophiles?

A
  1. Growth Optimum: 20-40
  2. Minimum: 25-20
  3. Maxlife: 45

a. majority fall into this group
b. includes bacteria that live in association with or cause disease in animals
c. bacteria from humans have optimum 37

34
Q

What are Thermophiles?

A
  1. Optimum at 55-65
  2. Minimum: 45
  3. Maximum: 80

a. Grow in compost heaps, dung heaps, hot springs
b. Enzymes and nucleic aiids very heat-stables
c. membrane lipids more saturated than those of mesophiles - intact at high temperature

35
Q

What are Hyperthermophiles?

A
  1. Grow: 90-100
  2. Optimum temperature: 80-113
  3. Minimum below 55

a. include species which grow in hot areas of ocean floor

36
Q

What are Black Smoker Bacteria?

A
  1. Grow in sulphide chimneys
  2. On ocean floor that spew out sulphide-rich superheated water at temps. above 350
  3. Bacteria from these grow at 113
  4. Vent water kept liquid at higher pressure due to depth of water.
37
Q

What are Halophiles?

A
  1. Most bacteria are inhibited by high concentration of salt
  2. Halophiles such as Halobacterium spp can tolerate high salt levels can colonise saline lakes
  3. Cell wall may be damaged, low salt concentration

Cell biology (6 decks)

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