Study of Bacteria
Contents
• Morphological classification of
bacteria
• Structure of bacterial cell
• Study of bacterial
– Flagella
– Pili and fimbriae
– Capsule
– Cell wall
– Cell membrane
– Mesosomes
– Cytoplasmic contents
– Ribosomes
– Plasmids
– Inclusion bodies and types
Intended Learning objectives
At the
end of this lecture student will be able to
• Classify bacteria based on their
morphology
• Reproduce the structure of a
bacterial cell and identify the various parts
• Explain the significance of
different bacterial structures
• Differentiate between gram positive
and gram negative cells
• Explain the functions of different
bacterial structures
• Explain the various inclusion bodies
found in bacterial cytoplasm
• Explain bacterial spore formation
and its significance
Summary
• Basic shapes of bacteria – cocci,
rods, vibrio, spirilli
• Flagella – used in bacterial
locomotion
• Parts of flagella – Basal body,
hook, filament
• Flagella arrangement – monotrichous,
amphitrichous, lophotrichous, peritrichous
• Axial filament – present in
spirochetes
• Basic shapes of bacteria – cocci,
rods, vibrio, spirilli
• Flagella – used in bacterial
locomotion
• Pili and fimbriae – basically organs
of adhesion
• Bacterial cell wall – gram positive
and gram negative
• Major differences between gram
positive and gram negative cell wall
|
Gram |
Gram |
|
Thick |
Thin peptidoglycan |
|
No LPS |
LPS |
|
Teichoic |
Teichoic |
|
No |
Periplasm |
• Plasma membrane – lipid bilayer
membrane acts as a selective barrier for the entry and exit of materials
• Cytoplasm contains nucleoid (DNA),
ribosomes (70s) and inclusion bodies
• Endospores are resting cells formed
during unfavourable conditions
• Spores can survive extreme heat,
lack of water, and exposure to many toxic chemicals and radiation
• Inclusions are reserve deposits
• Metachromatic Granules
• Polysaccharide Granules
• lipid Inclusions
• Sulfur Granules
• Carboxysomes
• Gas Vacuoles
• Magnetosomes
