Bacterial morphology, structure of the bacterial cell, cell organelles, Gram staining.

Essential components of prokaryotes

Nucleoid
Cytoplasm
Cytoplasmic membrane
Plasmid
Ribosomes

Non-Essential components of prokaryotes

Cell wall
Capsule(glycocalyx)
Flagella
Endospore
Granules

Cytoplasm

Gel-like, colloidal solution (cytosol) Contains 70–80% water, dissolved ions, nutrients, enzymes, nucleotides, ribosomes, and proteins.

Cytoplasm function

• Site of biochemical processes
• Site of protein synthesis (ribosomes)
• Storage function– nutrients, metabolites

Cytoplasmic Membrane

Phospholipid bilayer in which proteins are embedded

Cytoplasmic membrane Functions

• Regulation of permeability
• Energy conversion
• Cell communication
• Determines and maintains cell structural elements

Gram-positive cell wall

• Peptidoglycan layer (NAM, NAG, peptide cross-links)
• Teichoic acids (glycerol-phosphate, ribitol-phosphate polymers, lipoteichoic acid), 50% of the cell wall
• Carbohydrates, proteins

Gram-negative cell wall

• Periplasmic space (gel-like, contains soluble proteins, hydrolases, antibiotic-degrading enzymes, heavy metal neutralizing compounds, carrier proteins, bacterial toxin subunits, oligosaccharides)
• Outer membrane (with LPS layer)
• Porins
• Outer membrane proteins
• Bayer’s adhesion zone

• LPS –Lipopolysaccharide– a highly toxic, non-secreted endotoxin Components
- Lipid A→ a phospholipid; identical or similar in all Gram-negative bacteria
-R core (R-core or inner core) → the inner, highly conserved region adjacent to Lipid A; responsible for synthesizing the outer, distal elements (R mutants do not synthesize these distal components)
- O specific side chain (O-antigen) → the main surface antigen, exhibiting high antigenic variability

O-specific side chain (O-antigen)

the main surface antigen, exhibiting high antigenic variability

K-antigen

the capsular polysaccharides of Gram negative bacteria; they serve as antigenic determinants alongside lipopolysaccharides (LPS

H-antigen

the flagellar (flagellum) protein antigens of bacteria

Gram-negative and Gram-positive bacteria

Characteristics

Gram-negative and Gram-positive bacteria Characteristics

yup

Morphology of bacteria

cocci– spherical
bacilli (rod-shaped)
vibrio– „bent rod”
spirillum
spirochaete- spirals

morphological subtypes of cocci

monococci
diplococci
streptococci
tetracocci
sarcina
staphylococci

Morphological types of bacilli

diplobacillus; X; Y; V;
streptobacillus
coccobacillus
palisades
bundle
chain