Bacterial Structure And Morphology Flashcards
Innermost layer or the cell envelope, covering of the cytoplasm
Cell membrane
Composition of the cell membrane
Proteins and phospholipids
Controls the influx and efflux of substances
Cell membrane
Encloses the cytoplasm
Cell membrane
Various metabolic reactions take place here (because enzymes are mostly attached here)
Cell membrane
Suspended in the cytoplasm, that area is called the “Bacterial nucleoid” Composition: single, long, supercoiled, circular DNA
Chromosome
serves as the control center of the cell
Bacterial DNA
capable of duplicating, guiding cell division and directing cellular activities and 575-55,000 genes
Bacterial DNA
double-stranded DNA, suspended in the cytoplasm
Extra chromosomal DNA / plasmid
contains fewer than 10 to several hundred genes
Extrachromosomal DNA/Plasmid
contains fewer than 10 to several hundred genes
Extrachromosomal DNA/Plasmid
Extrachromosomal DNA/Plasmid
It is where various metabolic reactions takes place
Cell membrane
Holds the cytoplasmic particles especially the 70S ribosomes
Cytoplasm
contain starch, lipid, sulfur and iron that serve as nutrients of bacteria
Cytoplasmic granules
Location: Outer layer, between the cell membrane and capsule (if capsule is present)
Cell wall
Composition of the cell wall
Peptidoglycan/Murein
Peptide/Protein bonds that link the polysaccharide chains
Peptido
Polysaccharide chains (N-acetylmuramic acid + N-acetylglucosamine)
Glycan
Bacteria that doesn’t have a cell wall
Mycoplasma
Bacteria that don’t have a cell wall
Mycoplasma
Defines the shape of bacterial cell
Cell wall
Provides rigidity, strength, and protection
Cell wall
Determines the reaction to some bacterial stains
Cell wall
thicker cell wall, with techoic acid
Gram positive
thinner cell wall with Lipopolysaccharide (LPS) and phospholipid
Gram negative
are bacteria without cell wall; maycause chronic form of diseases such as Chronic Fatigue Syndrome, Lyme disease, Rheumatoid arthritis, and Sarcoidosis
Cell Wall-Deficient (CWD) or L-form bacteria
What structures are suspended in the cytoplasm of bacteria?
PolySome’s
Location: outside the cell wall
Glycocalyx
Composition: slimy, gelatinous material produced by the cell membrane and secreted outside the cell wall
Glycocalyx
not highly organized and not firmly attached to the cell wall; enables them to glide or slide along solid surfaces, and seem to protect bacteria from antibiotics and desiccation
Slime layer
highly organized & firmly attached to the cell wall; may be composed of polysaccharides, lipids & proteins
Capsule
anti-phagocytic
Capsule
stain that demonstrates the capsule; capsule appears as unstained halo around the bacterial cell, against a dark background
Negative staining
It is a capsular swelling reaction. A gold standard test for serotyping Streptococcus pneumoniae. Swelling of the capsule happens when the type-specific antibody combines with the capsule.
Quellung/Neufeld Reaction
Location: Outside, attached to the basal body in the cell membrane
Flagella
Location: Outside, attached to the basal body in the cell membrane
Flagella
protein appendages for bacterial motility
Flagella
Composition of flagella is 3 or more threads of protein called _____ that is twisted like a rope
flagellin
flagellum on one end of the bacterium
Monotrichous
tuft of flagella on one end of the bacterium
Lophotrichous
one or more flagella on each end of the bacterium
Amphitrichous
Flagella over the entire surface/perimeter of the bacterium
Peritrichous
flagella-like fibrils found in spirochetes that enable them to move in a spiral , helical, or inchworm manner
Axial filaments
Location: Arise from the cytoplasm and extend through the cell/plasma membrane, cell wall, and capsule (if present); common among Gram-negative
PILI/FIMBRIAE
Composition of pili that is polymerized protein molecules called
pilin
For bacterial adherence/attachment to surfaces
Somatic Pili
For transfer of genetic material from one bacterial cell to another (Conjugation)
Sex Pili
Location: Within the cytoplasm of the bacteria
SPORES (ENDOSPORES)
Composition: Copy of the chromosome, and some of the surrounding cytoplasm becomes enclosed and form the spore
SPORES (ENDOSPORES)
Enable bacteria to survive in adverse conditions, such as temperate extremes, desiccation, and lack of nutrients
SPORES (ENDOSPORES)
spore is produced at the end of the bacterial cell
Terminal spore
produced elsewhere in the cell
Subterminal spore
Example of bacteria that has sports
Bacillus and Clostridium species
Example of curve or comma-shaped bacilli
Vibrio cholerae and Vibrio parahaemolyticus (singly, curved bacilli) Campylobacter spp. (curve bacilli in pairs, appears like a seagull’s wing
AXIAL FILAMENTS/PERIPLASMIC FLAGELLA CAUSATIVE AGENT OF SYPHILIS
Treponema pallidum
TIGHTLY COILED SPIROCHETE
Treponema pallidum
Less tightly coiled Motility: Axial filaments
Borrelia spp.
CWD or L-form that appear in various shapes due to the
absence of cell wall
Pleomorphic bacteria
For fixation - so that the bacteria will stick to the slide; preserve the bacteria; serves as bacteriostatic agent
Methanol
Primary stain - serves as initial cell wall stain
Crystal violet (blue)
Reaction of Crystal violet stain
Gram positive: stains blue to purple
Gram negative: blue to purple
Mordant - forms an insoluble complex with the primary stain, increasing its uptake and fixing it into the cell wall (crystal violet-iodine complex)
Gram’s iodine (purple)
Reaction of grams iodine
Gram positive: blue to purple
Gram negative: blue to purple
Decolorizer - removes the primary stain
Ethanol
Reaction of ethanol
Gram positive: blue to purple
Gram negative: colorless
Secondary stain/ counterstain - provides contrast or differentiation
Safranin (red)
Reaction of safranin
Gram positive: blue to purple
Gram negative: red
All cocci are Gram postive, EXCEPT
Neisseria, Veilonella and Moraxella.
All bacilli are Gram negative, EXCEPT
Mycobacteria, Corynebacterium, Clostridia, Erysiphilothrix, Lactobacillus, Listeria, Nocardia, Actinomyces, and Bacillus.
All spiral organisms are reported as
Gram negative
Yeasts are reported as
Gram positive
Not Gram stained
Chlamydia, Ricketssia, Mycoplasma, Ureplasma, Spirochete, Legionella
Steps of G/S:
VIAS
Gram negative cocci
NEVErMORe (Neisseria, Veilonella, Moraxella)
Gram positive bacilli
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Rods in chains
Streptobacilli
Cocci in clusters
Staphylococci
Cocci in chain
Streptococci
Bacilli in pairs
Diplobacilli
Cocci in pairs
Diplococci
Cocci in packets of eight
Octads
Short bacilli
Coccobacilli
Spirillum
Spirochete
Stacks of bacilli
Palisade
Varied shapes
Pleomorphic
Diplobacilli
M. Boris - gram negative
Octads
S. ventriculli - gram positive
Coccobacilli
H. Influenzae - gram negative
Diplococci
N. gonorrheae - gram negative
Palisade
C. diphtheriae - gram positive
Streptobacilli
S. moniliformis - gram negative
Staphylococci
S. aureus - gram neg
Spirochete
T. pallidum -gram neg
Pleomorphic
M. pneumoniae
Streptococci
S. pyogenes - gram pos