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Micro > 1 - Morphology & Ultrastructure > Flashcards

1 - Morphology & Ultrastructure Flashcards

1
Q

What constitutes a species (5 things)

A
  1. Mating constraints (classical)
  2. Visible characteristics (Gram, shape, spores)
  3. Metabolism
  4. Surface structures
  5. Molecular Relatedness
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2
Q

Biochemical tests can assess relatedness only if…

A

the cell is metabolically active

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3
Q

Five tools for assessing relatedness

A
  1. Biochemical tests
  2. Numerical taxonomy
  3. DNA optical mapping (restriction digest)
  4. Serotyping
  5. Direct gene sequence comparisons
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4
Q

Optical map assembly involves _____ DNA molecules on a glass chip

A

linearized

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5
Q

Serotyping (strain typing) involves what 4 characteristics?

A
  1. Antigens
  2. Antobiotic/phage sensitivity profiles
  3. Toxin production
  4. surface molecules
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6
Q

6 important bacterial phyla

A
  1. Proteobacteria (a, ß, g, Σ)
  2. Chlamydiae
  3. Bacteroidetes
  4. Actinobacteriae (Myco, coryne, Actinomyces)
  5. Spirochaetae (Trep, Lepto, Borrelia)
  6. Firmicutes
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7
Q

Mycoplasma cell shape

A

pleiomorphic (and small)

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8
Q

Mycoplasma energetics/metabolism?

What does its membrane require

A

Obligate intracellular parasites

Cholesterol

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9
Q

Mycoplasma does not contain a _____, only a ________.

A

No cell wall

only a membrane

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10
Q

Various archaea shapes

A

cocci, rod, spiral, others

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11
Q

Two types of energetics found in archaea

A

Lithotrophs, heterotrophs

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12
Q

Three energetic properties of archaea

A
  1. many extremophiles
  2. some produce methane
  3. protein synthesis resembles eukaryotes
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13
Q

Archaea envelope – it does not have ______ but has a ________

A

No peptoglycan *

Has a cell wall

**pseudo-pg, polysacch, protein

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14
Q

Major difference in archaea lipids

A

Ethers (Other life has esters)

The lipids also have** Branched Isoprene chains**

(instead of unbranched fatty acids)

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15
Q

Prokaryotes reproduce via ____. They have a _______ chromosome usually.

A

binary fission

Single circular chromosome

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16
Q

Cytoplasm of prokaryotes contains….

A

membrane invaginations

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17
Q

Specific membrane structures of prokaryotes

A

Mesosomes

Phycobilisomes, chromatophores

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18
Q

Cytoplasm of prokaryotes contains what?

A

Inclusion bodies (insoluble polymers, poly beta-OH butyrate, starch, glycogen, sulfur, polyphosphate granules)

Somal bodies (protein-bound vesicles, gas vesicles, magnetosomes (membrane-bound), carboxysomes)

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19
Q

Bacterial chromosome is…. (three properties

A
  • anchored to membrane
    • highly folded (not histones)
    • few thousand genes
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20
Q

Important functional sites in bacterial cytoplasm

A

Enzymatic reaction centers

(reaction centers depend on DNA, mRNA and protein localization)

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21
Q

Plasma membrane can be made more fluid by…

A

Lowering temp

Shorter or more unsaturated fatty acids

22
Q

Phosopholipid bilayer does not contain

A

sterols

(except mycolic acid)

23
Q

Bacteria do not perform

A

Endocytosis

*Need transporter molecules

24
Q

What is the Rocker-Switch mechanism?

A

external and internal binding sites for transported solute

and a “bottleneck” that is sometimes a selectivity filter

25
Q

Bacteria require _____ to export proteins such as ____ and ______

A

Secretory systems

hydrolases, toxins

26
Q

Four steps to gram stain

A

Crystal Violet

Iodine

Alcohol

Safranin

27
Q

PG backbone made of

A

GlcNAc - MurNAc linked beta 1-4

28
Q

C6 O-acetyl MurNAc is resistant to

A

lysozyme

29
Q

PG side chain made of

A

tetrapeptide

*can vary

30
Q

Differences in PG side chain among types of bacteria

A

G- usu. have DAP at #3

G+ usu. have lysine

31
Q

PG pentapeptide cross bridge is only in…

A

G+

32
Q

Two molecules in glycan chains of PG

A

NAG and **MURNAc **(N acetylmuramic acid)

33
Q

Tetrapeptide uses what weird molecules?

A

D amino acids

34
Q

6 steps in PG synth

A
  1. Pentapeptide side chain is added to UDP-NAM
  2. UDP-MurNAc-5aa is then transferred to bactoprenol, NAG is added
  3. Bactoprenol is phosphorylated and flips sides
  4. New monomer is removed from BP and added to a space in wall by transglycosylation
  5. Transpeptidation (5th Ala is lost)
  6. BP is Dephosphorylated and flips again
35
Q

LPS is in what cell type?

A

Gram -

36
Q

LPS constituents

A
  1. O antigen
  2. Core polysaccharide
  3. Disaccharide diphosphate
  4. Lipid A
  5. Fatty acids
37
Q

Synthesis of LPS (3 steps)

A
  1. Core (monosaccharide) added to lipid A on Inner surface of inner membrane – Lipid A flips to periplasmic space
  2. Repeat unit is made in cytoplasm and carried to Periplasmic space by bactoprenol (and added to lipid A core)
  3. LPS moves to Outer membrane via bridging proteins
38
Q

Bacterial species may alter what part of LPS?

A

O antigen

these define SEROTYPES (strains)

39
Q

____ lack O antigen, and instead produce variant form of LPS called ________

A

Neisseria

Lipooligosaccharide

40
Q

Bacteria contain polysaccharide capsule (except ______. What does it have instead?)

A

Bacillus anthracis

It has poly D-Glu

41
Q

Purposes of capsule (glycocalyx)

A
  • Adhesion to surfaces (Strep mutans – uronic acids)
  • Anti phagocytic (Strep pneumoniae)
  • Immune mimic (NmB, EcK1 – sialic acid)
42
Q

Function of Pili/Fimbriae

A
  1. Hold together during conjugation
  2. Attach cells to surfaces (Streptococcal M protein is a minor protein at tips of pili)
  3. Antigenic - cells can vary antigens to evade host defenses (antigenic variation in N. gonorrhoeae)
  4. Motility (twitching… alternate extension and retraction)
43
Q

Flagella structure

A

Filament composed of flagellin*

*H antigen

44
Q

Location of flagella is…

A

species specific

45
Q

How does locomotion by flagella occur?

A

repulsion of charges from **proton flow ** through Mot A/B proteins

46
Q

What is a C ring?

A

switch that allows rotation to change direction

47
Q

Conformations of C ring

A
  1. CCW = cell swims
  2. CW = cell tumbles randomly

this allows chemotaxis, a sensing of chemical gradients TEMPORALLY (not spatially)

48
Q

What are S-Layers? Who are they especially prominent in?

A

Single crystalline protein that surrounds some cells

(esp. prominent in Archaea)

49
Q

Function and characteristic of S-layers

(one of each)

A
  1. Molecular sieve (anti-complement)
  2. Variations in lattice arrangement are characteristic of the species
50
Q

Flagella filament (propeller) is connected at the ______

A

Hook

(universal joint)

Micro (3 decks)

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