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Microbiology (Cell wall) Flashcards

1
Q

What provides extreme strength and rigidity to cell wall?

A

Peptidoglycan and tetrapeptide crosslinking

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2
Q

Interbridge

A

Linking just the tetrapeptide

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3
Q

Gram Negative Tetrapeptide linkage

A

They directly link two tetrapeptide

1. tetrapeptide contain diaminopimelic acid (from lysine)

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4
Q

Gram positive tetrapeptide linkage

A

They link two tetrapeptide via a pentaglycine

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5
Q

Thickness of Gram positive crosslinking

A

200-800A

Penicillin can prevent this crosslinking

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6
Q

Gram positive Teichoic acid

A
  1. Used for adherence
  2. Binds to Mg ions
    Types:
    -Two glycerols linked via D-ala and D-glucose
    -Ribitols linked via D-ala and D-glucose
    -lipoteichoic integrated into the cytoplasmic membrane by way of fatty acids
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7
Q

Mycobacterium

A
  1. Acid fast bacteria that are exterior to peptidoglycan

2. Order from outside to inside: Myeloic acid, arabinogalactan, peptidoglycan

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8
Q

Contents of outer membrane of Gram negative

A
  1. Lipopolysaccharides
  2. proteins
  3. lipoproteins

This outer membrane is physically toxic to us= Endotoxin

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9
Q

Lipopolysaccharides are made up of:

A

O-specific polysaccharides
Core polysaccharides
Lipid A

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10
Q

O-specific

A
  1. O antigen
  2. 6 carbon sugar motifs
  3. repeating units of undefined length
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11
Q

Core proteins

A
  1. Defined length

2. Composed of: glucose, galactose, heptose, KDO, NAG

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12
Q

Lipid A

A

Diphospho-NAG and Fatty acids

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13
Q

Porins

A
  1. Integrated in both leaflets of the outer membrane
  2. Transfer nutrients from the outside/in (small)
  3. Trimers
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14
Q

Periplasm

A

Between outer membrane and cytoplasmic membrane and allows for transfer

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15
Q

Gram Negative

A

1-2 layers thick and penicillin is less effective towards it

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16
Q

Protoplast

A

wall less bacteria that can survive in an isotonic solution

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17
Q

Prokaryotes and Protoplast

A

Some prokaryotes are free living protoplast that can survive without a cell wall because of thick outer membrane. Mycoplasma is a prokaryote that can survive in a protected habitat. When prokaryotes are subjected to penicillin for a long period of time they can revert to an L form

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18
Q

Cell wall of Gram positive and Gram Negative

A

Alcohol can decolorize Gram Negative outer membrane because it is lipid rich and is insoluble to crystal violet

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19
Q

Movement of Flagella

A

Swarming-Cordinated motion of many rotating helical flagella

Swimming-movement of an individual rotating flagella

Twitching-Extension of pili and retracting it back to it

Gliding-involoves focal adhesion proteins

Sliding-uses a surfactant

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20
Q

Characteristics of flagella

A
  1. Anchored to : cell wall and cytoplasmic membrane
  2. Made up of several proteins
  3. Filamentous part: only 1 proteins, uses PMF, and stimulant to innate immune response
  4. 40,000 Daltons
  5. Moves 60 cell lengths per second
  6. Rotates 2400 RPM
  7. Ring is surrounded by motor proteins
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21
Q

PMF of flagella

A

As protons (H) moves out of cell they are associated with a negative charge and causes a slight ratchet of the ring

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22
Q

Counterclockwise rotation of flagella

A

causes the flagella to run

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23
Q

Clockwise rotation fo the flagella

A

causes the flagella to tumble

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24
Q

Direction of rotation is controlled by:

A

sensory and response proteins

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25
Chemotaxis
directed movement of organism due to chemical Positive: Movement in the direction of increasing chemical concentration Negative: Movement in the direction away from chemical
26
Filment H antigen
Induces antibodies of our immune system
27
Monotrichous
Single flagella
28
amphitrichous
bipolar flagella
29
lophotrochous
tufted flagella (all at one end)
30
Peritrichous
flagella surround perimeter
31
Gliding motion
Ratcheting movement moves outer membrane proteins in opposite direction of cells that are moving on a slime layer
32
Pili (fimbriae)
1. Are made up of proteins called pillin 2. Fimbriae are used for attachment 3. Pili are used for conjugation 4. Attach to salivary components 5. In both gram positive and gram negative
33
Prokaryotes cell surface layer
1. S layer 2. Capsule (rigid polysaccharides) 3. Slime layer (diffuse polysaccharides)-loosely attached
34
S-layer
Selective Sieve to let low molecular weight molecules through
35
Capsule and Slime layer
1. For attachment and Phagocytosis
36
Strep Mutans
Adhere to teeth and cause caries Use Glucosyl transferase to break down sugars to form slime layer (levans and dextrans) Sucrose is broken down into: Levans=glucan (alpha 1-3, alpha 1-6) Dextrans=fructans (beta 2-6, beta 1-2
37
Glucosyl Transferase Enzymes
3 isoenzymes : BDC b-is insoluble and form alpha 1-3 glucose moieties d-water soluble and form alpha 1-6 glucose c- form both alpha1-3 and alpha 1-6 glucans (make antibodies against C)
38
Storage Granules or Inclusions
1. Used when you have an unbalanced growth 2. High molecular weight 3. Plug into TCA cycle Volutin-metachromatic granule that stains red with toluidine blue and has polybetahydroxybutyric acid (polymer of C4 fatty acids)
39
Glycogen storage granules
Storage of glucose (alpha 1-4 and alpha 1-6) Stain red with potassium iodine Glycogen phosphorylase (get glucose)-how strep works at night
40
Endospore
1. Highly resistant bacteria produced by by gram positive bacteria 2. Can survive: heat, chemicals, radiation, drying 3. Must use sporicide to kill
41
Endospore genus
Clostridium(anaerobic) and Bacillus(aerobic)
42
Sporulation
grows slow due to lack of nutrients
43
Forming spore
takes 40 hours and 500 genes
44
Four layers of Endospore
inside-out 1. core wall-peptidoglycan 2. cortex-thickest peptidoglycan with little crosslinking 3. Coat-keratin-like protein 4. Exosporium-lipoproteins
45
Carbon and energy source during germination for endospores
small acid soluble proteins
46
Spore characteristics
1. divalent calcium 2. dipicolinic acid that binds calcium 3. Due to this pH is one unit lower than usual (5.5-6)
47
Characteristics of vegetative cell
1. nonrefractile 2. low calcium and dipicolinic acid 3. high metabolism 4. MRNA present 5. Water content is 80-90% 6. pH of 7 7. Toxic state 8. GerminationEmer
48
Characteristics of Endospores
1. Refractile 2. high calcium and dipicolinic acid 3. low metabolism 4. No MRNA 5. pH of 5.5-6 6. Water content 10-25% 7. Acid soluble proteins 8. Resistance
49
Emergence of vegetative cell
due to endospore activation, germination, subsequent outgrowth
50
Chemoorganotrohphic
1. obtain energy from oxidation of organic compounds | 2. Have organic compounds going to CO2 and O2 while rest of bi-products do anaerobic respiration
51
chemolithotrophic
1. obtain energy from oxidation of inorganic compounds 2. This is a way to get organic compounds they need from inorganic ones 3. CO2 does own biosynthesis from rest of bi-products
52
Phototrophic
Use light as an energy source
53
Photoheterotrophy
Organic compound biosynthesis
54
Photoautotrophy
CO2 biosynthesis
55
Culture Media
1. Defined or undefined in nutrients | 2. Agar added to liquid media to immobilize cells so that they grow in colonies that can be isolated and visible
56
Bacterial growth media
1. Broth-nutrients in a liquid form 2. Agar-nutrients in a gelled liquid 3. Nutrient broth or Nutrient agar- water, dried beef extract, and peptone
57
auxotrophs
can no longer make own nutrients
58
Chocolate Agar
Hemolyzed blood used for neisseria meningitdis
59
Blood agar
whole blood cells used for strep pyogenes
60
Selective media
Allows only certain species of bacteria to grow | EX-Eosin methylene blue agar-Gram negative bacteria
61
Differential media
Bacteria that grow take on unique colonies characteristics
62
McConkeys Agar
Selective and Differential and used for GI organisms that cause diarrheal disease pathogen (lactose neg) Non-pathogen (lactose pos)
63
Mannitol Salt Agar
Selective-differential for staph in food poisoning Staph grow well in high salt Staph aureus causes agar to turn yellow instead of red
64
Endergonic
Positive | Energy required for anabolism
65
Exergonic
Negative | energy available for catabolism
66
oxidation
1. Negative reduction 2. Loss of electron (electron donor) 3. The greater the negative reduction the more it is a nutrient source
67
Reduction
1. Positive reduction | 2. Gain of electrons (electron acceptor)
68
Electron tower
Top-Bottom Electron donors (oxidizers) Mediate Electron transfer Electron acceptors (reducers)
69
Electron Carries
1. Freely diffusible 2. NADH-electron donor (oxidizer) 3. NAD -electron acceptor (reducer)
70
NAD
Senses nutrients in the cell and are able to transfer electron between 2 dissimilar molecules
71
Results of fermentation and respiration
Energy conservation in a cell (ATP generation) 1. Fermentation -result of substrate level phosphorylation - internally supplied electron acceptors - produces pyruvate 2. Respiration-depends on PMF and oxidative phosphorylation - externally supplied electron acceptors
72
Aerobic respiration
Terminal electron acceptor: O2
73
Anaerobic respiration
Terminal electron acceptor: something other than O2 it has to be sulfates, nitrates, nitriles
74
PMF
Electrons transported through ETC and protons are extruded to outside of cell membrane and this will energize cell membrane. Used for: symporters, antiporters, flagella, ATP synthase H is returned to membrane via ATPase to form ATP 3H=1ATP
75
Respiration
Oxidation of organic compounds to release more energy than during fermentation
76
TCA
Generate NADH and FADH which are reducers Supply: Amino Acids, lipids, Purine, pyrimidines, Catabolic and Anabolic
77
Bacterial Growth
1. Increase in mass 2. Increase in number 3. Binary fission
78
Formation of Biofilm
1. Bacteria use flagella to move close to surface 2. Once close to surface bacteria use pili to attach to surface 3. They retract and start crawling on the surface 4. Bacteria start to secrete adhesive extracellular matrix components 5. Formation of colonies (50+) 6. Formation of biofilms 7. Antibiotic resistant
79
ECM of Biofilm
1. DNA/RNA 2. Proteins 3. Polysaccharides Hold biofilm together

Microbiology (4 decks)

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