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15 Cards in this Set
- Front
- Back
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Main shapes |
Spherical - cocci Rod-like - bacilli Spiral- spirilla Chains- strepto Bunches- staphylo |
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Basic structure |
Capsule Cell wall Fimbriae or pili Plasma membrane - mesosomes Nucleoid Cytoplasm - 70s ribosomes ,storage granules chromatophores( photosynthetic bacteria) |
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Flagellum |
Three parts- Basal granule Hook Main filament |
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Basal granule |
Gram -ve Two sets of rings M,S,P,L from inner to outer side M ring anchored to plasma membrane and P ring to peptidoglycan of cell wall Gram +ve Only one set the inner attached to plasma membrane . Outer ring not attached. |
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Hook |
Penetrates through the cell wall and connects the main filament to basal granules |
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Main filament |
Protein - flagellin 4-5 micrometer long 100-300 micrometer in diameter ,1/10 diameter of eukaryote Use - locomotion , longitudinal wave like action |
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Fimbriae or pili |
Hair like appendages. Shorter than flagella. 70 to 100A. E.coli - type 1 pilin. F-pillus - f pilin. Longer thicker with a terminal knob. Organs of attachment Special pili - bridge form male to female , transfer of DNA. |
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Capsule |
Secreted by cell Polysaccharides or disaccharide sometimes polypeptides with one or two different amino acids . Macro- 0.2 micrometer visible in light microscope Micro -not seen under microscope . Demonstrated immunologically. |
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Cell wall |
Characteristic shape and protects cell form high osmotic pressure( 20 atm) Plant and algae- cellulose Fungi- chitin Bacteria- polysaccharides of glucose galactose mannose etc. Peptidoglycans - 95% in gram -ve 5-10% in +ve Lipids - 20 % in gram -ve , traces in +ve Proteins +ve - alanine and glutamic acid along with smaller amounts of other amino acids -ve - wide range of amino acids. |
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Internal membrane system |
No definite endoplasmic reticulum Presence of internal membrane maybe be concealed due to density of packed ribosomes. Lack vacuoles |
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Mesosomes |
Cell membrane becomes invaginated and folded to form mesosomes Thought to be equivalent to mitochondrion Consists of vesicles and tubules Well developed in bacilli. Lipid composition similar to cell membrane but differ in proteins. Increases surface area for transport systems . Nucleoid attached to it and functions in replication of DNA during cell division |
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Plasma membrane |
Lipids and proteins 50-65% Polar lipids like glycerophospolipids , fatty acids- 10-20 carbons Gram positive - small amounts of glycolipids , pore formation Wide range of proteins than eukaryotes. ETC occurs hence functionally similar to mitochondria. Function- osmotic barrier Prevents unrequited substances from entering the cell. ETC |
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Ribosomes |
10,000 30% of weight . 30-50% protein 50-70% RNA Not attached to ER , free in cytoplasm 70s Protein synthesis In groups polyribosomes or polysomes |
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Storage granules |
Large stores energy or organic compounds High molecular weight can store without increasing osmolarity Types Polymetaphosphate granules - po3- Polybetahydroxybutyrate (lipids) Polyglucan ( branched molecules resembles glycogen of mammalian. |
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Nucleoid |
Not enclosed in the nuclear envelope DNA helix shown to be circular in several bacteria. Highly folded and attached to the plasma membrane at one point Two extra methylated bases - 6-methylaminopurine and 5-methylcytosine. DNA usually called chromosome but different from that in eukaryotes. No his tone protein A small amount of extra chromosomal DNA present in the form of episodes or plasmids Plasmids- circular DNA duplexes attached to plasma membrane capable of autonomous replication. Partly or wholly incorporated into chromosomal DNA. |
