Prokaryotes
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Gram-negative Cell Wall
these are organisms that do not contain a true nucleus.
These organisms also do not contain organelles such as
mitochondria, endoplasmic reticulum and Golgi
apparatus. All their functions take place in the cytoplasm
or cytoplasmic membrane.
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Bacteria
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these are unicellular organisms that don not have a
nucleus, a nuclear membrane, and membrane-bound
organelles; these are examples of prokaryotic cells.
Cell Envelope
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it is the outermost structure of the bacterial cell.
it is composed of an outer membrane (Gram-negative
bacteria), cell wall, periplasm (Gram-negative bacteria),
and plasma membrane.
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Outer Membrane
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Cell Wall
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it is a rigid structure that maintains the shape of the cell.
it is composed disaccharide-pentapeptide subunits and
teichoic acid or lipoteichoic acid.
its synthesis and structure have been the target of
antimicrobial agents.
it prevents bacterial cells from rupturing when the osmotic
pressure inside the cell is greater than pressure outside the
cell.
It serves as point of anchorage for flagella.
it determines the staining characteristics of species.
Gram-positive Cell Wall
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it is composed of a very thick peptidoglycan layer.
it consists of glycan chains of alternating N-acetyl-Dglucosamine (NAG) and N-acetyl-D-muramic (NAM) acid.
it contains a negatively charged teichoic and contributes
to the charge of the cell wall.
it is prime target of microbial agents like penicillin which
prevents the synthesis of peptidoglycans.
its outer membrane is composed of proteins,
phospholipids and lipopolysaccharides(LPS).
the inner membrane is composed of a thin peptidoglycan
layer, which is the reason for its high susceptibility to
mechanical breakage.
it has porins that contribute to the permeability of the cell
wall.
it contains periplasmic space which is involved in
peptidoglycan synthesis
it doesn’t contain teichoic.
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The strong negative charge of the _____________ is an
important factor in evading phagocytosis.
it allows hydrophilic compounds to enter the cell through
the porins.
It acts as barrier to toxic substances that prevents
movement inside the cell.
Lipid A
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LPS region that is a major constituent, an endotoxin
Antigenic O
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LPS region that which is the specific polysaccharide
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they are vital in evading the host defenses
They contribute to the negative charge of the bacterial
surface, which stabilizes the membrane structure.
is also considered endotoxin
LPS
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Gram-positive Bacteria
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Flagellar structure: 2 rings in the basal body
has high inhibition by basic dyes
Gram-negative Bacteria
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Flagellar structure: 4 rings in the basal body
has low inhibition by basic dyes
Acid-fast Cell Wall
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it has gram-positive structure
aside from peptidoglycan layer, it contains a waxy layer
of glycolipids and fatty acids (mycolic acid) that is bound
to the exterior of the cell wall.
Some examples of the cells that have this kind of cell wall
are Mycobacterium and Nocardia.
Mycolic acid
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has the strong hydrophobic structure that affects the
permeability of the acid-fast cell wall
Sterols
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Prokaryotes that do not have cell wall contain _______ in
their cell membrane
Absence of a Cell Wall
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some examples of cells that have this kind of cell walls are
Mycoplasma and Ureaplasma.
Genome
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Plasmid
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it is the deepest layer of the cell envelope and the internal
matrix of the cell wall.
it consists of a phospholipid bilayer that surrounds the
cytoplasm. This layer is embedded with proteins.
it functions as the mitochondria, Golgi apparatus and
lysosomes of eukaryotic cells.
it acts as osmotic barrier.
it regulates the transport of solutes across the membrane
as well as the generation of chemical energy (ATP).
it is the site of respiration and photosynthesis.
Ribosome (Non-membranous structure)
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it is the site of protein biosynthesis and gives the cytoplasm
the granular structure
it contains RNA and proteins
it is 70S in size and separates into two subunits, 50S and 30S.
it is an extrachromosomal, double-stranded element of
DNA that is associated with virulence.
It is located in the cytoplasm and serves as a site for genes
to code for antibiotic resistance and toxin production.
it is not essential for bacterial growth so a bacterial cell
may or may not contain this.
it is sometimes disappears during cell division, and it can
make bacteria (mostly Gram-negative bacteria)
pathogenic.
Large Plasmid
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Plasma Membrane
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it consists of a single, circular chromosome
it appears as diffused nucleoid or chromatin body that is
attached to a mesosome (sac-like structures).
is responsible for the production of beta-lactamases that
provide resistance to beta-lactam antibiotics like penicillin
and oxacillin
Small Plasmid
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is
resistant to tetracyclines and chloramphenicol
Inclusion Bodies
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they serve as the energy source or food reserve of the
bacteria
composed mainly of polysaccharides, they lessen osmotic
pressure
Some examples of these structures are glycogen,
cyanophysin
granules,
poly-beta-hydroxybutarate
granules, carboxysomes
(cyanobacteria, nitrifying
bacteria and thiobacilli), gas vacuoles (cynaobacteria,
halobacterium and thiothrix) and polyphosphate granules
(volutin or metachromatic granules)
Babes-Ernst Bodies Corynebacterium diphtheriae
Bipolar Bodies
Yersinia pestis, Pasteurella and Bordetella
Sulfur Granules
Nocardia and Actinomycetes
Much’s Granules
Mycobacterium tuberculosis
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Endospores
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these are small, dormant structures located inside the
bacterial cell.
they aid in the survival of bacteria against external
conditions
they are produced within vegetative cells of some Grampositive bacteria
they are composed of dipicolinic acid and calcium ions
(calcium dipicolinate)
Endospore Formers
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Bacillus and Clostridium are examples
Slime Layer
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Clostridium tetani spore location
Subterminal Spore
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Clostridium botulinum spore location
Central Spore
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Bacillus anthracis spore location
Sporogenesis
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is the process of spore formation
Germination
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is the end of the spore’s dormant stage
Glycocalyx
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it is an outward complex of polysaccharides on the
bacterial surface and other cells.
It helps the bacteria to attach to the surface of solid
objects or tissue.
it appears as capsule or a slime layer.
Capsule
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it is an organized material that is firmly attached to the cell
wall
it is made-up of polysaccharide polymers
it is an unorganized material that is loosely attached to the
cell wall; it is also made-up of polysaccharide polymers.
it can either inhibit phagocytosis or aid in the adherence
of the bacteria to the host tissue or synthetic implants
Flagellum
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Terminal Spore
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it protects the bacteria (virulence factor) from the attacks
of human defense system cells since it resists phagocytosis
and desiccation.
it is an exterior protein filament (flagellin) that rotates and
thus causes bacteria to be motile
it is important in the survivability and pathogenic ability of
bacteria
Atrichous
without flagella
Monotrichous
single flagellum in one end
Amphitrichous
single flagellum in both ends
Lopotrichous
tuff/group of flagella on one end or both
ends
Peritrichous
flagella is spread over the whole surface
Gliding Motility
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motility that exhibited by cyanobacteria, myxobacteria,
and capnobacteria.
Hanging Drop Method
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true motility and Brownian movement are best observed
through this method
True Motility
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with ________, the bacteria seems to be going in a definite
direction
Brownian Movement
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with ________, the bacteria bounces back and forth
rapidly due to the bombardment of molecules of water
Taxis
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the movement of bacteria toward or away from a
particular stimulus
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these are hair-like, proteinaceous structures that extend
from the cell membrane to the external environment (2
micrometers in length)
these aid in the attachment of the bacteria to surfaces
some examples of bacteria with common ____ are
Neisseria gonorrhoeae and Pseudomonas
Pili
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Sex Pilus
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an essential part of the genetic transfer/conjugation
process
Somatic Pilus
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a virulence factor/organ of attachment
Introns
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a sequence of base pairs in DNA that interrupts the
continuity of genetic information
Cytoskeleton
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is a cytoplasmic element-which includes the keratin and
other microfibrils-that functions as supportive system within
a cell, especially with epithelial cells.
S-layer
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archaebacteria contain a protein or glycoprotein wall
structure
Archaebacteria
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these organisms are classified as aerobes, facultative
anaerobes or obligate anaerobes
they may be stained either as Gram-positive or Gramnegative in various shapes such as spherical, rod and
spiral (pleomorphic)
they grow and survive under extreme environmental
conditions
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they reproduce through binary fission, fragmentation or
budding
some examples are Methanospirillum, Halobacterium,
and Sulfolobus.