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MICRB 265 > Week 4 > Flashcards

Week 4 Flashcards

1
Q

archaea membrane desc.

A

-lipids are ether-linages not ester linkages
-attached to glycerol (diether) + phosphate =glycerol phosphates
-lipids are not fatty acids but phytanyl (isoprene unit) = bulky
-bilayer (biphytanyl or crenarchaeol)- common in thermophiles vs monolayer (phytanyl)

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2
Q

archaea cell envelope options

A

1) pseudomurein
2) methanochondrotin + s-layer (inner)
3) S layer
4) protein sheath + s layer (inner)

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3
Q

pseudomurein

A

-N -acetylglucosamine (like pepti.) + N-acetylalosaminuronic acid linked by B (1,3) linage - lysozyme insensitive
- peptide link to minuronic acid and peptide cross-link form

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4
Q

archaeallum uses ____

A

ATP not PMP to spin

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5
Q

archaeal hami is what>

A

similar to pili
extends but has 3 prong hook at the end and brances

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6
Q

bacterial growth curve is plotted on ____

A

log scale so exponential phase is linear

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7
Q

bacterial growth curve parts

A

-lag -nutrients are taken in, enzymes are made, and replication
-exponential (log) -popn growth is doubling -organisms dependent
-stationary- out of nutrients, growth slows, endospores created
-decline/death -rupture of PM, destruction of DNA

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8
Q

growth refers to ____

A

popn growth rather than growth of individual cells

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9
Q

generation doubling time (def.)

A
  • time required for the population to double in size
  • varies depending on species of microorganism and
    environmental conditions
  • range is from 10 minutes for some bacteria to several
    days for some eukaryotic microorganisms
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10
Q

growth outside lab

A
  • almost always slower than optimal
  • progression through stages is not linear
  • virtually always part of a mixed culture
  • frequently part of a biofilm
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11
Q

Asexual reproduction (def.)
Sexual reproduction (def.)

A

-new cells from one set of chromosomes yields daughter cells which are genetic clones of parent
-combination of genetic material from two organisms yields new organism

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12
Q

microbial growth by _____

A

-asexual reproduction
-microbial “pseudosexual” reproduction

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13
Q

types of asexual reproduction

A
  • Binary fission
  • Budding
  • Fragmentation- long part often fungi that breaks off into different parts
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14
Q

types of pseudosexual reproduction

A
  • Conjugation
  • Transformation
  • Transduction
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15
Q

pseudosexual reproduction (def.)

A

the combination of genetic material from different organisms but not required for growth of the cell

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16
Q

the most common way for bacteria to divide

A

binary fission

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17
Q

binary fission steps

A

1) cell elongation
2) septum formation: barrier between two cells with peptidoglycan
3) pinching: completion of septum; formation of walls + cell separation

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18
Q

DNA replication in binary fission

A

1) binding of DNAA to oriC initiates replication
2) Blocking of oriC regions by SepA; cell elongation
3) segregation of chromosomes
4) Z-ring formation-part of the septum
5) cell division

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19
Q

cytokinesis steps

A
  • Replication of cytoplasmic contents (ribosomes, inclusions, etc.)
  • Septation occurs (cross walls between daughter cells)
  • Site is selected by FtsZ (exactly in the center of the
    cell)
  • Z ring is assembled
  • Z ring is linked to plasma membrane
  • Cell wall biosynthetic machinery is synthesized
  • Constriction of cell and septum formation
20
Q

The E-coli divisome (Z-ring)

A
  • 10,000 FtsZ molecules polymerize into ring at the
    center of the cell
  • Ring is tethered to plasma membrane by ZipA and FtsA
  • Localizes peptidoglycan biosynthesis machinery to the center of the cell -> requires ATP
21
Q

How does the cell know where the center is?

A

Min C,D,E

22
Q

Z-ring localization

A

1) Min CD prevents Z-ring from forming (found all over the cell)
2) When cell is ready to divide, Min E comes to the center (no MinCD in the center of the cell so Z-ring forms)
3) Ftz ring + divisome complex
4) septum forms
5) loss of MinE so Min CD formed again

23
Q

Peptidoglycan synthesis occurs in ____

A

middle of cell anchored by Ftz ring

24
Q

general peptidoglycan biosynthesis

A
  • Synthesis of the building blocks
  • Synthesis of the disaccharide-peptide repeat unit (a.a added one at a time except last d-ala which are added at the same time)
  • Translocation from cytoplasm to periplasm
  • Transglycosylation (loss of pyrophosphate-linking repeat unit)
  • Transpeptidation (DAP forms cross link with Ala of pentapeptide and removes 2nd d-ala to form tetrapeptide)
25
Q

peptidoglycan biosynthesis steps

A

F6P (from glycolysis) –> Glucosamine 1-PO4 (acetyl-coa -> coa) –>NAG 1-PO4 (UTP ->Pi) –> UDP-NAG (PEP -> Pi, NADPH -> NADP+) —> (transpeptidation) –> UDP-NAM pentapeptide

26
Q

nutrient requirements

A
  • Macronutrient (required in relatively large quantities and play principal roles in cell structure and metabolism = carbon, hydrogen, and oxygen)
  • Micronutrient (trace elements (manganese, zinc, and nickel), present in much smaller amounts and are
    involved in enzyme function and maintenance of
    protein structure)
  • Growth factors/vitamins
  • Iron (siderophores)
27
Q

Temperature affects ____

A

-growth rate

28
Q

temperature optima and growth - types of bacteria classes

A

-psychrophile (4 C) - ex. sno algae
-mesophile (39 C), body temp.
-thermophile (60 C)
-hyperthermophile (> 70C)

29
Q

bacteria can adapt to ____

A

high temps

30
Q
  • Osmolarity (def.)
  • Tonicity (def.)
A

-the total concentration of solute
-the concentration of permeable solutes Hypotonic/isotonic/hypertonic

31
Q

Osmotolerant microorganisms do what?

A

-grows well in media with high solute concentrations (ex. yeast)

32
Q

halophiles?

A

grow well in NaCl; adjust internal osmolarity

33
Q

nonhalotolerant?
halotolerant?
halophile?
extreme halophile?

A

-E.coli
-doesn’t grow better in salt but can survive (ex. staph. aureus)
-need salt to grow
-needs a lot of salt

34
Q

pH optima
neutrophile?
acidophile?
alkaliphile?

A

-5.5<pH<8
-ph<5.5
-pH>8

35
Q

obligate aerobes?
facultative aerobes/anaerobes?
microaerophilic aerobes?

A

-O2 required
-not required but growth in better with O2
-required but at low levels

36
Q

obligate anaaerobes?
aerotolerant anaaerobes?

A

-O2 is harmful or lethal
-not required, and growth no between when O2 present

37
Q

Growth in oxygen correlates with microbes

A
  • energy conserving metabolic processes and the electron transport chain (ETC) and nature of terminal electron acceptor
38
Q

Oxygen produces reactive oxygen species (ROS) which are
toxic: ____
Aerobes produce protective enzymes: _____

A

-superoxide, hydrogen peroxide, hydroxyl radical
-Superoxide dismutase, catalase, peroxidase

39
Q

Microbes on land and water surface grow at ____
Some Bacteria and Archaea live in _____

A

-1 atm
-the deep sea (high hydrostatic pressure)

40
Q

Barotolerant?Barophilic?

A
  • adversely affected by high pressure but not as bad as nontolerant
  • require pressure because they’ve changed their
    membranes to adapt to high pressure
41
Q

increase [bacteria] = ___

A

increase OD (optical density)

42
Q

Defined media?

A

-is one where the exact chemical composition of the media is known
* Sucrose, potassium phosphate, ammonium
phosphate, MgSO4, FeSO4, MnSO4, water

43
Q

Complex media?

A

is one where the exact chemical composition of the media is not known.
* Tryptone, yeast extract, NaCl, water

44
Q

Selective media?

A

selects for the growth of some organisms by promoting their growth and/or inhibiting the growth of other organisms.
* Antibiotics
* High salt
* Essential amino acids/sugars

45
Q

Differential media?

A

differentiates between organisms growing on one plate.
* pH indicator
* Blood
* Essential sugars

46
Q

how serial dilutions work?

A

-Take 1 ml of sample in 9 ml broth (dilute tenfold 10-1)
-plate count x dilution factor = CFU/ml of original sample

47
Q

CFU stands for

A

colony forming units

MICRB 265 (12 decks)

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