MT2 Content Flashcards

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1
Q

How is selective permeability achieved?

A
  1. substrate-specific carrier proteins (permeases)
  2. Dedicated nutrient-binding proteins patrolling periplasmic space
  3. Membrane-spanning protein channels/pores
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2
Q

ABC Transporters

A

-powered by ATP
-found in all 3 domains of life
-gram - employ peiplasmic binding proteins
-gram + & archaea employ substrate-binding proteins on external surface of cytoplasmic membrane

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3
Q

2 main types of ABC Transporters

A

-Uptake: taking things in, critical for transporting nutrients
-Effflux: pump shit out, generally used as multidrug efflux pumps

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4
Q

Growth Cycle

A
  1. Growth: increase in # of cells
  2. Binary fission: cell division when cell doubles in size
  3. Septum: Partition of cells, creating 2 daughter cells
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5
Q

Planktonic growth

A

-growth as suspension

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6
Q

Sessile growth

A

-attached to surface
-can develop into biofilms

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7
Q

Biofilms

A

-forms in stages
-planktonic cells attach
-sticky matrix forms

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8
Q

Microbial Mats

A

-multilayered sheets w/ diff. organisms in each layer

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9
Q

Closed Culture

A

-limited nutrients
-also called batch culture

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10
Q

Bacterial Growth Curves

A
  1. Lag phase: no increase in number of living cells (takes a while to adapt)
  2. Log phase: exponential increase in # of living bacterial cells
  3. Stationary phase: plateau in # of living cells; death rate = birth rate
  4. Death phase: exp. decrase in living cells
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11
Q

Continuous Culture

A

-all cells in pop. achieve steady state
-chemostat constantly adds & removes equal amounts of culture medium (ensures log growth)

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12
Q

Biofilms

A

-surface attached communities
-can be constructed by 1 or multiple species
-can form on range of surfaces
-difficult to dislodge
-protect bacteria from chemicals

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13
Q

Biofilm development involves?

A

-adherence of cells to a substrate
-formation of microcolonies
-formation of complex channeled communities that generate new planktonic cells

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14
Q

Biofilm Life Cycle

A
  1. Attachment to monolayer by flagella
  2. Microcolonies
  3. Exopolysides (EPS) production
  4. Mature biofilm
  5. Dissolution & dispersal
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15
Q

Molecular constitution of biofilms

A

-EPS (polysaccharides in gram + and cellulose in gram -)
-proteins
-eDNA

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16
Q

Quorum Sensing

A

-how bacteria communicate
-triggered by c-di-GMP
-AHL is signalling molecule in gram -

17
Q

Cardinal Temperatures

A

-min, max, & optimum temps at which an organism grows

18
Q

Psychrophile

A

-low, found in cold env.

19
Q

Mesophile

A

-midrange, most commonly studied

20
Q

Thermophile

A

-high, found in hot env.

21
Q

Hyperthermophile

A

-very high, found in very hot habitats

22
Q

Water Activity

A

-how much water is available for use
-measured as ratio of solution’s vapour pressure relative to that of pure water
-inversely related to osmolarity

23
Q

Osmophiles

A

-live in env. where sugar is high as a solute

24
Q

Xerophiles

A

-organisms able to grow in very dry env.

25
Q

Compatible solutes

A

-presence does not inhibit organism’s biochem
-usually made by bacteria to protect internal water when placed in hypertonic media

26
Q

Strict Aerobes

A

-can only grow in O2

27
Q

Microaerophiles

A

-grow only at lower O2 levels

28
Q

Strict anaerobes

A

-die in the least bit of O2

29
Q

Aerotolerant anaerobes

A

-grow in O2 while having fermentation-based metabolism

30
Q

Facultative anaerobes

A

-can live w/ or w/o O2
-possess ability for both anaerobic & aerobic

31
Q

DNA Binding Regulatory Proteins

A

-control initiation of transcription at gene promoters

32
Q

Sigma Factor

A

-helps RNA pol. bind to certain DNA sequences & add specificity to RNA pol.
-housekeeping ones are for genes that are always expressed
-alternative ones do other genes

33
Q

Stringent Response

A

-when nutrient scarcity leaves many ribosomes idle
-triggers ppGpp synth.
-binds to RNA pol., and lower’s it’s ability to transcribe RNA
-decrease in growth

34
Q

Alarmones

A

-produced by RelA when ribosomes stall (stress signal)
-ppGpp & pppGpp
-help bacteria with stress
-slow down/stop certain cellular processes

35
Q

Morphogenesis

A

-transition to stalked cell
-triggered by c-di-GMP in C. crescentus

36
Q

Autoinducer

A

-membrane permeable second messenger that allows cells to regulate gene expression based on density of cells in env.
-allows for quorum sensing

37
Q

Flagellar Motion

A

-CCW = smooth swimming/run
-CW = tumbling