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1.
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Capsule or Slime layer
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Outermost thick mucilaginous layer
|
-
Adhesion to the host
body.
-
Protection against phagocytes and
viruses.
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2.
|
Cell wall
|
-
Present below glycocalyx.
-
Made up of peptidoglycan (murein) in Eubacteria; pseudomurein in
Archaebacteria.
-
Consists of polysaccharide chains cross-linked with short amino acid
chains.
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-
Provides rigidity and support.
-
Determines cell shape.
|
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3.
|
Plasma membrane
|
-
Innermost layer of cell envelope.
-
Forms the boundary of cytoplasm.
-
Chemically, lipoproteinous in nature.
-
Phospholipid bilayer with intrinsic and extrinsic proteins.
|
-
Protects cell from injury.
-
Selective permeability.
-
Intercellular communication.
-
Site for respiration, photosynthesis, etc.
-
Serves as point of attachment.
|
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4.
|
Mesosomes
|
Invaginations of the plasma membrane in the form of vesicles, tubules and lamella.
|
-
Cell wall formation.
-
Replication of DNA and distribution to daughter cells.
-
Increase the surface area of plasma membrane.
-
Contains respiratory enzymes.
|
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5.
|
Cytoplasm
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Colourless, semi-fluid, ground substance present inner to the cell membrane.
|
|
|
6.
|
Inclusion bodies
|
-
Non-living structures present in cytoplasm.
-
Include storage granules.
-
Organic inclusion bodies – Cynophycean starch, protein
granules.
-
Inorganic inclusion bodies – Volutin (phosphate), sulphur, iron granules.
|
Storage of reserve food.
|
|
7.
|
Ribosomes
|
-
Small, sub-microscopic ribonucleoprotein particles.
-
Made up of RNA and proteins.
-
70S type ( 50S and 30S)
|
Site of protein synthesis.
|
|
8.
|
Nucleoid
(Genophore)
|
-
Naked, double stranded DNA molecule.
-
Histone proteins, nucleolus and nuclear membrane absent.
|
Genetic material of the cell.
|
|
9.
|
Plasmids
|
Autonomously replication, double stranded circular DNA molecules present in cytoplasm.
|
-
Antibiotic resistance
-
Fertility.
|
|
10.
|
Flagella
|
One or more long, fine, thread-like structures present in bacteria.
|
Help in locomotion.
|
|
11.
|
Pili
|
Long, few, thick tubular structures made up of protein pilin.
|
Formation of conjugation tube for exchange of genetic material.
|
|
12.
|
Fimbriae
|
Small, narrow structures produced in large numbers (300-400 per cell)
|
Attachment of bacteria to solid surface or host tissue.
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