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Microbiology PMY 3 > Intro To Prokaryotes > Flashcards

Intro To Prokaryotes Flashcards

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1
Q

Describe a Coccus/Cocci bacterium/bacteria

A

A single round cell

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2
Q

Describe a diplocpccus/diplococci bacterium/bacteria

A

A pair of cocci

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3
Q

Describe a tetrad (pl. tetrad) bacterium/ bacteria

A

Group of four cocci

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4
Q

Describe a Streptococcus(pl. streptococci)

A

A chain of cocci

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5
Q

Describe a Staphylococcus (pl. stsohylococci ) bacterium/ bacteria

A

Cluster of cocci

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6
Q

Describe a Bacillus(pl. Bacilli)

A

Single-rod shape

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7
Q

Describe a Streptobacillus(pl. streptobaccilli)

A

A chain of rods

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8
Q

Why is smaller better for prokaryotes?

A
  • More surface area relative to volume (higher surface area to volume ratio)
  • Substance enter and diffuse quickly(absorb nutrients faster)
  • Growth rate is affected by nutrients( small cells can grow faster than big ones)
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9
Q

What is the function of the Capsule slime layer of the bacteria?

A
  • Prevent bacteriophage attachment
  • Evade phagocytosis
  • prevent bacteria from getting dried out
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10
Q

What is the function of Pili Fimbriae for bacteria?

A

Allows bacteria to :

  • Attach to surfaces or tissues
  • Attach to each other
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11
Q

What is the function of the cell wall of the bacteria?

A
  • Keep cell rigid

- Contain all cellular components

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12
Q

What is function of the cytoplasmic membrane of bacteria?

A
  • Control access in/out site
  • Site of metabolism
  • Enzyme functions
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13
Q

What is the function of endospores inclusion vacuoles in bacteria?

A

To assist bacteria in surviving environmental changes

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14
Q

What is the function of flagellae in bacteria?

A
  • To allow bacteria to change location in liquid environment
  • Move towards something good
  • Move away from something bad
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15
Q

What are the key layers of a Gram negative bacterial cell?

A
  1. Cytoplasm ( ribosomes, DNA, lots of enzymes)
  2. Cytoplasmic/cell membrane
  3. Peptidoglycan
  4. Periplasmic space
  5. Outer membrane
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16
Q

What are the key cell layers of a gram positive bacterial cell?

A
  1. Cytoplasm (ribosomes, DNA, lots of enzymes)
  2. Cytoplasmic/cell membrane
  3. Peptidoglycan
  4. Periplasmic space
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17
Q

Describe the cytoplasm of the prokaryotic cell?

A
  • Water
  • DNA and Ribosomes
  • Enzymes
  • Proteins
  • Inclusion bodies e.g. storage granules
  • Endospores
  • NO organelles( no mitochondria, ER, Golgi apparatus, nucleus etc.)
  • site of many cellular processes(others take place at cytoplasmic membrane)
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18
Q

Describe the cytoplasmic membrane in prokaryotes

A

Fluid mosaic model-interface with the external environment (outside of the cell)

  • phospholipids- 30%-40%
  • proteins- 60%-70%

Phospholipid belayer :

polar heads - hydrophilic
Fatty acyl heads- hydrophobic

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19
Q

What are the functions the prokaryotic cell membrane ?

A
  1. Transport - from the inside to the outside of the cell and vice versa
  2. Energy production-
    a. Proton motive force
    b. Oxidative phosphorylation
    c. Phosphorylation
  3. Metabolic processes
  4. Motility- energy for flagella movement.
  5. Communication- receptors for sensing if environment is favorable or unfavorable (detecting and sending signals)
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20
Q

What function does Cell wall have in controlling what enters and leaves a prokaryote?

A

While present in both gram positive and gram negative, cell wall does not control the flow of what goes in or out

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21
Q

Differentiate simple diffusion and passive diffusion

A

Simple diffusion: Materials pass through a membrane without the help of proteins

Passive diffusion: materials diffuse across the plasma membrane with the help of membrane proteins

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22
Q

Explain what is Bulk Transport

A

Consists of endocytosis and exocytosis

Endocytosis: absorption of larger molecules that are polar in charge and unable to diffuse through hydrophobic cell membrane

Exocytosis: expulsion of larger molecules that are polar in charge and unable to diffuse through hydrophobic cell maybe

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23
Q

What is the peptidoglycan cell wall of prokaryotes?

A

“The bacterial exoskeleton”

A multi-layered mesh around the cell

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24
Q

What is the function of the peptidoglycan cell wall?

A

Defines cell shape- coccus, bacillus, vibrio etc.

Maintains osmotic integrity inside of the cell

-it is necessary in order to maintain a high intracellular osmotic pressure(prevents lysis of the cell)

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25
Q

What is a prokaryotes’ gram staining character defined by?

A

Thickness, how the layers are cross linking and gram positive bacteria much thicker peptidoglycan layer

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26
Q

Between gram positive and gram negative cell walls, which is thicker?

A

Gram positive bacteria are much thicker

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27
Q

What is a peptidoglycan?

A

A large molecule that is unique only to bacteria

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28
Q

Describe the contents of the peptidoglycan Layer

A

Polysaccharide:
N-acetylglucosamine( NAGj
N-acetylmuramic acid(NAM)
-some amino acids

  • Long chains made next to each other that are then cross-linked
  • Mesh-like net around the cell
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29
Q

Gram negative and gram positive have different….

A

Cross links

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30
Q

What type of linkage occurs between NAM and NAG ?

A

B 1-4 linkage

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31
Q

What are the differences between teichoic acids and lipoteichoic acids?(Gram positive bacteria )

A

Teichoic acid= acidic polysaccharide

 - Polymer of phosphate plus ribitol or glycerol
 - If anchored into cell membrane= lipoteichoic acid
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32
Q

What are the functions of teichoic acids and lipoteichoic acids?

A
  • Can be a substantial component cell wall
  • Anchor other proteins; bind molecules for transport e.g. Mg 2+
  • Responsible for overall negative charge of cell surface
  • Targets for vaccine and drug development
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33
Q

Where are teichoic and lipoteichoic acids?

A

Gram positive bacteria

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34
Q

Bacterial endospores enable resistance to:

A
  • Drying
  • Chemicals
  • Heat
  • Radiation
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35
Q

What are the functions of bacterial endospores?

A
  • Survival adaptations from unfavorable environments
  • Released when the producing cell dies
  • help with long term survival(>100-1000s of years
  • Dehydrated, no active protein synthesis or metabolism, unique layers and components
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36
Q

What is sporulation?

A

Formation of endospores

37
Q

What is germination?

A

Return to vegetative growth when the conditions are favorable

38
Q

Describe the 2-phase life cycle of bacterial endospores

A

Vegetative cell- bacterial cell is metabolically active and growing

Endospores-in unfavorable environments the cell stores its DNA in the core of the cell and when the timing is right, and conditions are favorable it will become metabolically active again

39
Q

Describe bacterial endospores and their special features

A
  • Unique cellular structure
  • Chemical and enzymatic resistance
  • Specialized peptidoglycan
  • Germ cell wall
  • Major permeability barrier
  • house’s cell’s DNA
  • Dipicolinic acid(10% of spore, dry weight)
40
Q

What is the function of the core layer of the endospores?

A

Mostly dehydrated and metabolically inactive ; contains dipicolinic acid; chromosomal DNA and ribosomes

41
Q

What is the function of the cortex layer of endospores?

A

Occupies most of the spore volume;- made up from a unique thick layer of special type of peptidoglycan

42
Q

What is the function of the coat layer of endospores?

A

Contains keratin; impermeable to most toxins and chemicals(contributes to resistance)

43
Q

What is the function of the exosporium layer of the endospores structure?

A

Thin outer glycoprotein layer

44
Q

What is the periplasm in gram negative bacteria?

A

The area between the outer membrane and cytoplasmic membrane

45
Q

What is the periplasm of gram positive bacteria?

A

Space between the cytoplasmic membrane and peptidoglycan

46
Q

What is the function of periplasmic space?

A
  • Transport(binding proteins)
  • Breakdown of food molecules (hydrolysis enzymes)
  • Chemoreceptors (chemotaxis: detecting chemical signals)
47
Q

Describe the periplasmic space/ periplasm

A

Gel-like rather than true space

High concentration of proteins

48
Q

What type of bacteria has an outer membrane?

A

Gram negative

49
Q

What is the purpose of the outer membrane?

A

Part of the bacterial defense against the action of antibiotics: some don’t penetrate the cell because their entry is blocked by the outer membrane

50
Q

Describe the porins of the outer membrane of gram negative

A

Outer membranes contains porins

  • proteins that form channels/tunnels through the outer membrane
  • Porin size vary, blocking or allowing the entry of certain products
51
Q

Describe the permeability of the outer membrane of gram negative bacteria

A

Not permeable to proteins or large molecules (traps proteins in periplasmic space -e.g. degradation enzymes, binding proteins, chemoreceptors)

52
Q

What is the outer most layer of gram negative outer membrane?

A

Lipopolysaccharides

53
Q

What are the layers of the endospores?

A

Core layer

Cortex layer

Coat layer

Exosporium layer

54
Q

Lipopolysaccharide is also known as …

A

“Endotoxin”

55
Q

What are the 3 components of lipopolysaccharides?

A
  1. O-specific polysaccharides
  2. Core. Polysaccharide
  3. Lipid A
56
Q

Describe the O-specific polysaccharides in lipopolysaccharides

A
  • Very variable between different species

- “O antigenl

57
Q

Describe the core polysaccharide in lipopolysaccharides

A

Comprised of 10-15 different sugars

58
Q

Describe Lipid A in lipopolysaccharides

A

It anchors the lipopolysaccharide in the phospholipid layer. The active “toxic” component

59
Q

Why are lipopolysaccharides medically important?

A
  • Important antigen
  • Contributes to some of the symptoms for some gram-negative infections
  • Immune system responds to the lipopolysaccharides (good in small amounts, bad in higher)
    • Fever and chills
60
Q

What happens when a bacterium is in a harsh environment?

A

Sporulation (6-8 hours)

61
Q

How is sporulation done?

A
  • bacteria copies it’s genome and pinches the plasma membrane
  • spore septum forms
  • a double membrane forms around spore septum
  • peptidoglycan fills the spore to finalize the spore forming
  • endospores is released from the spore with the copier genome and finds a favorable environment to germinate
62
Q

Differentiate slime layer and capsule

A

Slime layer- less of it, relatively easy to move, loosely organized

Capsule- thick, not easy to remove, highly organized, Capsular Polysaccharides (CPS)/ K Antigen

63
Q

How can bacteria change the color of an algae plate?

A

-If bacteria are producing a capsule, it changes hows the colonies appear when they are grown on an agar plate

64
Q

What is a function of the capsule in prokaryotes?

A

-Some capsules can be used to create vaccines to protect against infections e.g. meninges

65
Q

What is the size fimbrae?

A
  • 2-10 nm diameter

- 1-2 microns long

66
Q

What is the fimbrae known as?

A

Short attachment, common pili

67
Q

What is the size of the Pillus?

A
  • 2-10 nm in diameter

- from 10 - over 20 microns long

68
Q

The pillus is involved in_____________

A

Conjugation

69
Q

A prokaryote has atrichous flagella, what is this?

A

No flagella

70
Q

A Prokaryote has a polar flagella, what is this?

A

Single flagella at one or both ends

71
Q

A prokaryote has a lophotrichous flagella, what is that?

A

Bunch at the end

72
Q

A prokaryote has amphitrichous flagella, what does this mean ?

A

Bunched flagella at one point

73
Q

A prokaryotic cell has Peritrichous flagella, what is that?

A

Flagella all around cell

74
Q

Differentiate spirillum and spirochete bacteria

A

Both are spiral but spirilium is shorter and thicker than spirochete

75
Q

What is a coccobacillus?

A

Mix of a rod and circular bacteria

76
Q

Describe the difference in staining in gram positive and negative bacteria

A

Gram positive- thick peptidoglycan and will stain purple

Gram negative- thin peptidoglycan and will stain punk by Safarin counter stain

77
Q

Explain the mesh work of gram positive bacteria

A

NAG and NAM alternating

Each NAM has a tetrapeptide sticking out connecting to another tetrapeptide via pentagon INR bridge

78
Q

Describe the mesh work of the gram negative cell wall

A

Alternating chains of NAM and NAG

with a different tetrapeptide than gram positive

Tetrapeptide from NAM connected by a peptide bond

79
Q

Name 2 medically important endospores ?

A

Clostridia( tetanus) and bacillus (B anthracis)

80
Q

What is a terminal endospores?

A

Endospore at the end of the cell

81
Q

What is a sub terminal endospore?

A

Endospore is between the terminal and central

82
Q

What is a central endospore?

A

Spore in the center of the cell

83
Q

What part of lipopolysaccharides cause symptoms?

A

The toxic lipid A

84
Q

What 3 structures are external to cell wall?

A

Capsule, flagella and fimbrae pilli

85
Q

How do bacterial capsules help their bacteria ?

A

Helps evade the immune system

86
Q

Why is motility important?

A
  • gain access to different areas/body sites
  • moves in response to stimulus
    • chemotaxis
    • move around body in a clockwise or anti clockwise motion

Not all bacteria are motile via flagella

87
Q

A bacteria moves around in a clockwise motion, also known as…

A

Tumbling motion

88
Q

A Bacteria moves around in an anti clockwise motion, also known as…

A

Linear. Motion

89
Q

What is the H antigen?

A

The hair like antigen- flagella antigen

Microbiology PMY 3 (24 decks)

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