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microbiology > microbio chapter 6 > Flashcards

microbio chapter 6 Flashcards

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Biology 101 flashcards
1
Q

oxygen requirements

A

-anerobic
-aerobic

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2
Q

Aerobic

A
  • utilize oxygen as terminal electron acceptor
  • 1 glucose in = 38 ATP made
  • utilize cellular respiration
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3
Q

What enzyme is present in aerobic bacteria

A
  • catalase is present to break down H2O2
  • hydrogen peroxide can be made accidentally because oxygen is the terminal electron acceptor
  • bacteria can do this 10k times/sec to prevent toxication
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4
Q

micro-aerobic

A
  • 2-10% O2
  • utilize aerobic respiration
  • common in ocean water and our intestines
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5
Q

facultative anaerobes

A
  • can live without oxygen
  • don’t need krebs cycle
  • but if oxygen is present, they will switch to oxygen use as terminal electron acceptor
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6
Q

anaerobic

A
  • non oxygen as terminal electron acceptor
  • usually a sulfur salt as terminal electron acceptor
  • 1 glucose in = 2-38 ATP made
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7
Q

strict anaerobes

A
  • oxygen is toxic
  • if exposed they die
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8
Q

pschotrophs/pschrophile

A
  • 0-20 degrees Celsius
  • their enzymes fall apart at temps higher than 20 degrees C
  • in nature live in snow fields, ice, and cold water
  • do not causes disease in humans
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9
Q

mesophiles

A
  • 15-45 degrees C
  • causes disease in humans because our temp falls in range
  • humane pathogens
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10
Q

thermophiles

A
  • 40-80 degrees C
  • can grow best above 45 degrees C
  • found in compost piles and hot springs
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11
Q

extreme thermophiles

A
  • 70 degrees and above
  • grow best above 80 degrees C
  • tend to be archaea
  • stabilize their proteins by extra H and covalent bonds between aa
  • do not causes disease in humans
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12
Q

pH requirements

A
  • acidophiles <7
  • basophiles >7
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13
Q

phases of microbial growth

A
  1. lag phase
  2. log or exponential growth phase
  3. stationary phase
  4. death phase
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14
Q

lag phase

A
  • bacteria are sensing the environment and ‘turning’ on
  • genes are needed to take advantage of the environment
  • cells do not reproduce immediately, they are actively synthesizing proteins/enzymes to utilize nutrients in media
  • organisms appear dormant but are not
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15
Q

log phase/exponential growth phase

A
  • bacteria utilize media surroundings to grow and reproduce
  • bacteria cells utilize binary fission to reproduce
  • 1 cell becomes 2, 2 become 4, 4 become 8…
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16
Q

stationary phase

A
  • cells run out of nutrients and become surrounded by their wastes
  • rate of reproduction decreases
  • eventually number of dying cells = number of cells reproduced
  • population is constant
17
Q

death phase

A
  • lack of nutrients and accumulation of waste
  • cells die faster than they reproduce
  • some cells remain alive and continue to metabolize/reproduce
18
Q

biofilms

A
  • primary residence of microorganisms in nature
  • 99% of bacteria utilize biofilms
  • account for 2/3 of infections bacteria in humans
19
Q

examples of biofilms causing diseases

A
  • gum disease
  • lung infection
  • cystic fibrosis: body lacks enzymes that make mucous thinner so mucous cannot drain and bacterial colonies continue to grow
20
Q

antibiotics with biofilms

A
  • bacteria cells that encounter antibiotics first will communicate with other bacteria cells in biofilm to upregulate genes for antibiotic resistance
  • serves as a head start for other bacteria cells to protect themselves
  • communicate through chemical signals
21
Q

teeth and biofilms

A
  • bacteria in biofilms digest nutrients and release acid on teeth
  • this can decay teeth and cause cavities
22
Q

sepsis

A
  • bacteria all over body
  • can lead to biofilm production
  • increases mortality rate if biofilms form in lungs, heart, arteries….
23
Q

mechanisms of resistance in biofilms

A
  • increase cell density and physical exclusion of antibiotics
  • bacteria cells can undergo individual physiological changes to increase antibiotic resistance
24
Q

biofilm development

A
  1. attachment
  2. multiplication
  3. exodus
  4. quorum sensing
  5. new cells and water channels
  6. escapers and new biofilms
25
Q

attachment

A

bacteria cells settle on a surface and attach

26
Q

multiplication

A
  • cells begin matrix production and secrete quorum sensing molecules
  • cells begin to multiply
27
Q

exodus

A
  • colony purposely gets rid of some bacteria that may take a longer time to grow
  • matrix adheres cells to one another and to their substrates
  • microenvironments are formed within biofilm
  • water channels are formed between groups of cells
28
Q

quorum sensing

A
  • microbes secrete molecules that act to communicate number and types of cells among members of the biofilm
  • cells have receptors to bind with molecules
  • if not enough molecules bind to bacteria cells, bacteria decide not to make enzymes otherwise it’s a waste of energy
  • if enough chemical signals are present, they can make enzymes
29
Q

new cell arrival

A
  • new cells can arrive to be part of biofilm
  • there can be different bacteria cells in one biofilm
  • biofilms attach to surfaces
  • members assume different roles in different areas in biofilm
30
Q

microbes escape

A
  • some bacteria cells can escape from biofilm and form new biofilms on different surfaces
30
Q

antimicrobial resistance

A

because biofilms can have many different bacteria cells it makes it harder for antimicrobial drugs to be effective

microbiology (10 decks)

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