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VMCB 121 Lecture > 5: Bacterial Fine Structures, Functions, and Synthesis > Flashcards

5: Bacterial Fine Structures, Functions, and Synthesis Flashcards

1
Q

3 types of bacterial shapes

A
  • spherical or coccus bacteria (monococcus, diplococcus, staphylococcus, tetracoccus, sarcina, streptococcus)
  • rods, or bacillus - bacillus, coccabacillus, palisades, diplobacillus, spore-former, streptobacillus
  • curved shapes of bacteria - vibrious, spirilla, spirochaetes

!!! see ppt for pictures

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2
Q

3 types of bacterial cell arrangement

A

cocci arrangement
bacilli arrangement
others like vibrios, spirilla, and spirochetes

!!! see ppt for pictures

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3
Q

5 types of cocci bacterial arrangement

A
  • diplococci - in pairs
  • long chains - repeated divisions in one plane (e.g., streptococci)
  • grape-like clusters - division in random planes (e.g., staphylococci)
  • tetrads - four cells in square pattern
  • cubical packets - eight cells in 3D cube (e.g., Sarcina genus)

!!! see ppt for pictures

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4
Q

type of bacterial arrangement wherein the bacterial cells are Bacilli split only across their short axes

shape of the rod’s end often vary with flat, rounded, cigar-shaped, or bifurcated

A

bacilli arrangement

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5
Q

4 types of bacilli arrangement

A

coccobacillus
bacillus
diplobacilli
streptobacilli
palisades

!!! see ppt for pictures

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6
Q

rod-shaped bacteria shaped bacteria that are curved to form distinctive commas or incomplete spirals (arrangement)

A

vibrios

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7
Q

long rods twisted into spirals or helices that are rigid (arrangement)

A

spirilla

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8
Q

long rods twisted into spirals or helices that are flexible (arrangement)

A

spirochetes

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9
Q

2 divisions of bacterial cell components

A

outer layer or cell envelope - cell wall and plasma membrane

cellular appendages - capsule, fimbriae, and flagella

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10
Q

a general term is a general term for any network of polysaccharide or protein containing material extending outside of the cell

A

glycocalyx (capsule/slime layer)

capsule - closely associated with cells and does not wash off easily

slime layer - easily washed away zone of more diffuse, unorganized material

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10
Q

7 functions of glycocalyx

A
  • promote attachment to surfaces
  • prevent phagocytosis
  • protect cell from adverse physical factors
  • promote stability of bacterial suspension by preventing aggregation and settling out
  • serve as virus receptor
  • depot for waste products
  • resistance to drying
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10
Q

the layer that lies just outside the plasma (cytoplasmic) membrane composed of mucopeptides (peptidoglycan or murein)

has two parts:
- periplasm (peptidoglycan)
- outer membrane

A

cell wall

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10
Q

6 functions of the cell wall

A
  • impart shape and rigidity to the cell
  • supports the weak cytoplasmic membrane
    against the high internal osmotic pressure of the protoplasm (ranges from 5 and 25 atm)
  • maintains the characteristic shape of the
    bacterium
  • takes part in cell division
  • functions in interactions (e g adhesion) with other bacteria and with mammalian cells
  • provide specific protein and carbohydrate receptors for the attachment of some bacterial viruses
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10
Q

compare the cell walls of gram-positive bacteria and gram-negative bacteria

A

gram-positive cell wall: uniformly dense consisting primarily of peptidoglycan (periplasm), with teichoic acid

gram-negative cell wall: very thin peptidoglycan layer and an outer membrane, with lipoprotein, and lipopolysaccharides (LPS)

!!! see module for photos

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10
Q

composition of cell wall peptidoglycan synthesis

A

overlapping lattice of 2 sugars that are cross linked by amino acid bridges

the two sugars:
- N acetyl glucosamine (NAG, AGA or GlcNAc)
- N acetylmuramic acid (NAM, AMA or MurNAc ): only found in the cell walls of
bacteria (with L-alanine, D-alanine, D-glutamic acid, Diaminopimelic
acid (DPA))

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11
Q
  • major barrier in the cell, separating the inside of the cell from the outside
  • lipid molecules are arrayed in a double layer with their hydrophilic polar regions externally aligned and in contact with a layer of protein at each surface
  • consists of lipoprotein with small amounts of carbohydrate
A

cell membrane

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12
Q

6 functions of the cell membrane

A
  • controlling the inflow and outflow of metabolites to and from the protoplasm
  • housing enzymes
  • housing many sensory and chemotaxis proteins that monitor chemical and physical changes
  • generates chemical energy i.e., ATP
  • cell motility
  • mediation of chromosomal segregation during replication
12
Q

a cellular appendage characterized as a slender threadlike portion, long, hollow, helical filaments originating in the bacterial protoplasm and extruded through the cell wall

A

flagella

12
Q

3 parts of a flagellum

A

filament - longest and most obvious portion which extends from the cell surface to the tip

hook - short, curved segment linking the filament to its basal body

basal body - embedded in the cell membrane, has four rings in gram-negative bacteria (L, P, S, and M)

12
Q

4 flagella arrangements

A
  • monotrichous - single flagellum
  • amphitrichous - single flagellum at both ends
  • lophotrichous - tuft of flagella at one or both ends
  • peritrichous - flagella surrounding the cell

trichous - hair
lopho - tuft
amphi - both
peri - around

13
Q

during flagellar synthesis:

A
  • during growth and assembly, protein components are added at the flagellar tip rather than at the base (does not need enzymes)
  • both the basal body and the filament have a hollow core
14
Q
  • short, fine, hair like surface appendages
  • shorter and thinner than flagella
  • originate in the cytoplasmic membrane and are composed of structural protein subunits termed *****
  • both in non-motile and motile strains
A

pili or fimbriae

*****pilins

15
Q

2 functions of fimbriae/pili

A

ordinary (common) pili - for adhesions that allow attachment

sex pili - longer and involved in the transfer of DNA during conjugation

16
Q

an internal bacterial cell component that is a viscous watery solution or soft gel cell material bounded by the plasma membrane

A

cytoplasm

17
Q

3 areas of cytoplasm

A
  • cytoplasmic area - granular
  • chromatinic area
  • fluid portion contain inclusion and vacuoles
18
Q
  • small, electron-dense particles in the cytoplasmic region responsible for all bacterial protein synthesis
  • has 30S and 50S subunit (S or Svedberg unit)
  • composed of rRNA and proteins
A

ribosomes

19
Q

3 types of RNA

A

messenger RNA (mRNA) - carry the genetic information needed to make proteins

ribosomal RNA (rRNA) - direct the catalytic steps of protein synthesis

transfer RNA (tRNA) - transfers the genetic information in the mRNA into functional proteins

20
Q
  • internal cell components that are not permanent or essential structures
  • usually for storage, and reduce osmotic pressure by tying up molecules in particulate form
  • consists of volutin (polyphosphate), lipid, glycogen, starch or sulfur
A

intracytoplasmic inclusions

21
Q

an intracytoplasmic inclusion component that function as storage reservoirs for phosphate, are highly refractive, strongly basophilic bodies consisting of polymetaphosphate

A

volutin/metachromatic/Babes-Ernst granules

22
Q
  • genetic material of a bacterial cell is contained in a single, long molecule of double-stranded DNA which can be extracted in the form of a closed circular thread about 1 mm long
  • does not possess nuclear membrane
    (separating them from the cytoplasm), nucleolus, and deoxyribonucleoprotein
A

nucleus

23
Q
  • suggestive of a spore or seed like form (endo means within)
A

endospores

24
Q

outer covering of endospores that make them resistant to heat, chemicals, and staining

A

protein keratin

25
Q

5 characteristics of endospores

A
  • can remain dormant indefinitely (not reproductive) but germinate quickly when the appropriate trigger is applied
  • metabolically inactive
  • stable for years
  • differ significantly from the vegetative or normally functioning cells
  • formed by GRAM-POSTIVE BACTERIA
26
Q

3 uses of endospores

A
  • importance in food, industrial, and medical microbiology
  • sterilization control
  • research
27
Q

5 parts of endospores

A
  • core: spore protoplast with cell structures
  • spore wall: innermost layer around the inner spore membrane, normal peptidoglycan
  • cortex - thickest layer with less cross-linked peptidoglycan
  • spore coat: surrounds the cortex
  • exosporium: (in some species) external loose covering which may have distinctive ridges and grooves

!!! SEE PPT FOR MODEL !!!

28
Q

3 types of shape and position of bacterial spore

A

non-bulging - oval central, spherical central, oval sub terminal

bulging - oval sub terminal, oval terminal, spherical terminal

free spore

!!! SEE PPT FOR IMAGES !!!

29
Q

4 structures formed during endospore sporulation (in order)

A

spore septum
forespore
spore coat
free endospore

30
Q

sporulation: an ingrowth of the plasma membrane that isolates a small portion of the cytoplasm and the newly replicated chromosome

A

spore septum

31
Q

sporulation: double layered membrane that surrounds the chromosome and cytoplasm

A

forespore

32
Q

sporulation: the outer layer of the two layers of the divided forespore

A

spore coat

VMCB 121 Lecture (5 decks)

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