Prokaryotic-Bacteria-Cell | Notes by UKSir | Cell Bio- 3

PROKARYOIC CELL  / Bacteria

Prokaryotic-Bacteria

Bacteria

Definition:

•      Bacteria may be defined as submicroscopic, prokaryotic, cell wall containing, omnipresent organism, mostly maintain their life cycle either as Saprophytic or as Parasitic or even as Symbiotic organism.

•      These are mostly Non-green structure, but Cyanobacteria are green.

•      Can multiply rapidly and can multiply approximately in ~ 20 mins.

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Shape or Form:

      1 Coccus-Spherical or Ovoid shape

-  Mono coccus- Present Single

- Diplo coccus- 2 cell present

- Tetra coccus- 4 cell attached

 - Strepto coccus- in chain shape

 - Staphylo coccus- irregular shape

 - Sarcina coccus- 3D structure

Bacterial-cell-type

2.      Bacillus- Small rod shape or elongated shape

- Diplobacillus (Two cells attached)

- Palisade bacillus (cells are Stack together)

- Strepto Bacillus (cells are in chain)

3.      Spirillum- Spirally coiled e.g – spirillium, spiriochaete

4.      Vibrio- Comma shaped eg-Vibrio cholera

5.      Stalked- Having a stalk eg- Caulobacter

6.      Budding- having many out growths. eg – Rhodomicrobium

Bacteria-Falagella

1.      Flagellated- with flagella

- Atrichous- No flagella

- Monotrichous- single flagella

- Amphitrichous- both end contain flagella

- Lophotrichous- tuft of flagella present at one end

- Cephalotrichous- tuft of flagella present at both end

- Peritrichous-flagella  all over the surface

Type of Bacterial cell :on the Basis of  stain

•     
Gram’s Staining was developed  by  Christian Gram in 1884

STEPS INVOVED IN THIS PROCESS:

Ø  Bacterial mass - Stain with alkaline crystal violet

Ø  After 30 to 60 sec they looks blue

Ø  0.5% iodine sol is added drop wise

Ø  wash with distilled water

Ø  absolute alcohol or acetone is added for few seconds

Ø  stain with safranin

Ø  Wash with distilled water

Ø  Observe under microscope

Gram-staining-procedure

Result

•      If Blue or Violet or purple Colour = Gram +ve Bacteria

 (Example - Bacillus subtilis)

•      If Colour is Pink / Red = Gram –ve Bacteria

 (Example - E.coli)

Reason of color difference:

Ø  Gram -ve bacteria : contain High lipid in cell wall,

which dissolve in Organic solvent like Acetone.

Due to which Gram –ve bacteria become colorless

 And looks Pink or Red after adding of Safranin.

 

Ø  Gram +ve Bacteria: contain less lipid In cellwall,

for which less color wash out. When safranin added,

 they looks either  Violet or Purple color.

 Want to Know about Cell, click link below :

https://uksirnotes.blogspot.com/2021/05/cell-introduction.html

        Want to know about Prokaryotic cell properties, Click link below:

https://uksirnotes.blogspot.com/2021/05/difference-prokaryotic-eukaryotic-cell.html