Ultra- Structure-Prokaryotic-Bacteria- Cell | Notes by UK Sir | Cell Bio- 4

Ultra Structure of Bacterial/ Prokaryotic cell:

Ultra Structure of Bacterial/ Prokaryotic cell:

Prokaryotic-cell-Ultrastructure

Want to know about Shape size of Bacterial cell, Gram staining Click the link below :

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

Want to know about difference between Prokaryotic and Eukaryotic cell, Click the Link below:

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

1.     Cell Envelope:

•      It is the Outer covering of the protoplasm

•      Consists of 3 Parts-

a)     Glycocalyx  b) Cell wall c) Cell membrane

a)GLYCOCALYX:

•      Present Outside to cell wall

•      Contain 2 layers =    Inner S- Layer and Outer Mucilage layer

•     

Mucilage layer :  is jelly like structure made up of Polysaccharide (Carbohydrate). Later it become hard Capsule.

•      S- Layer: made up of Poly peptide(Acidic AA)

Function:

·        Gives hardness and resistant power

·        Gives- Stickiness/Attachment with any surface

·         Protect from virus attack, Phagocytosis, Chemicals etc

·        S – layer Prevent from Lysozyme and chemicals

b)CELL WALL:

•      It is the Rigid/hard, solid, dead, covering of the cell.

•      A Periplasmic space between Plasma membrane and Wall is present.

•     
Wall thickness  =    in Gram +ve bacteria  – 20-80 nm

In Gram –ve bacteria  – 8-12

Bacterial-Cellwall

 

Composition:

·        Outer membrane =  Lipo poly saccharides

·        Inner membrane- Peptidoglycon/ Murein/ Mucopeptide + Protein+ carbohydrate + lipid

·        Peptidoglycon= NAG (N-Acetyl Glucosamine)+ NAM (N- Acetyl Muramic acid)

 (long chains  of NAG and NAM cross linked by small peptide chains)

·        In Gram +ve Bacterial wall = Peptidoglycon is 70-80% + Lipid= 10-20% + teichoic acids

·        In Gram –ve Bacterial wall = lipid is more- 20-30% and Peptidoglycon is less.

Gram-Positive-Negative-Bacteria

•      The main function of cell wall is to Give shape and Rigidity to cell.

c) Plasma membrane:

•      It is the Inner most layer of Cell envelope.

•      Plasma membrane is Elastic, semipermeable and  living in nature.

•      It is Just like the typical eukaryotic  membrane.(Lipoprotein in nature)

•      Made up of Lipid bilayer with proteins.

•      Also holds receptor molecules, mostly carbohydrate or saccharides.

•      Plasma membrane is Metabolically active  - show  respiration, lipid synthesis as well as cell wall material synthesis.

•      The main function of Plasma Membrane is to make a Covering or boundary around the cytoplasm.

2. Cytoplasm:

•      Cytoplasm is Living, viscous, transparent, jelly like substance.

•      It is Present  inside the membrane.

•      Cytoplasm is nothing but Crystal containing colloidal system.

•      It is Granular due large number of ribosomes.

•      Small gas vacuoles may present, but true vacuoles absent.

•      Prokaryotic cytoplasm don’t show any kind moment.

•      There are some Structures present in side cytoplasm:

a) Mesosome      b) Ribosome   c) Chromatophore

Want to know about Shape size of Bacterial cell, Gram staining Click the link below :

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

Want to know about difference between Prokaryotic and Eukaryotic cell, Click the Link below:

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

 

    So this is the Envelope  of Bacteria/ Prokaryotic cell. In next article we will see the special structure below cell membrane of Bacteria.