CELL WALL, CELL MEMBRANE, CELLULAR APPENDAGES Flashcards
• Rigid structure that surrounds the CM
CELL WALL
• Present in most bacteria
CELL WALL
• Composed of PEPTIDOGLYCAN
CELL WALL
o Exclusive to bacteria
o MUREIN
PEPTIDOGLYCAN
o Composition of PEPTIDOGLYCAN
Carbohydrate backbone
Peptide
Carbohydrate backbone
- N-acetylmuramic acid
* N-acetylglucosamine acid
• FOR CONFERING SHAPE TO THE CELL
CELL WALL
• PROTECTION FROM OSMOLYSIS
CELL WALL
• DETERMINE GRAM’S REACTION
CELL WALL
• SITE OF ANTIGENIC DETERMINATION
CELL WALL
• SITE OF ANTIBIOTIC FUNCTION
CELL WALL
digest peptidoglycan of the bacterial cell wall
antibiotics
- Certain types of cells have no walls or have very little material
ATYPICAL CELL WALL
o Smallest bacteria
o Has STEROLS in their CM
o Have no CW
- Mycoplasma species
o Wall-less normal cells
• L-FORMS
o Parent cell have cell walls but are affected by factors that cause digestion of cell wall
Chemical
Physical
o Types of L-forms
PROTOPLAST (G+)
SPHEROPLAST (G-)
- Composed of a SINGLE LAYER of peptidoglycan
GRAM-NEGATIVE CELL WALL: OUTER MEMBRANE: LPS
- Thinner (10 to 20%)
- 8 to 11 nm
GRAM-NEGATIVE CELL WALL: OUTER MEMBRANE: LPS
- Lies outside the thin peptidog. layer
GRAM-NEGATIVE CELL WALL: OUTER MEMBRANE: LPS
- Firmly linked to peptidg.
GRAM-NEGATIVE CELL WALL: OUTER MEMBRANE: LPS
GRAM-NEGATIVE CELL WALL is consists of:
o Lipopolysaccharides
o Lipoproteins
o Phospholipids
Large complex molecule that contains lipids and carbs
o Lipopolysaccharides
o Lipopolysaccharides is consists of 3 components
- LIPID A
- CORE POLYSACCHARIDE
- OUTER POLYSACCHARIDE
GRAM-NEGATIVE CELL WALL is bonded to lipoprotein in the
OUTER MEMBRANE
- Peptidoglycan of g- cell wall is founded in the
PERIPLASM
GRAM-NEGATIVE CELL WALL do not contain
TEICHOIC ACID
- More susceptible to mechanical breakage
GRAM-NEGATIVE CELL WALL
- Responsible for the symptoms associated with infections by gram (-) bacteria (Fever, dilation of blood vessels, shock, and blood clotting)
LIPID A
- Lipid portion of the LPS
LIPID A
- Embedded in the top layer of the outer membrane
LIPID A
- Functions as endotoxin
LIPID A
- Attached to lipid A
CORE POLYSACCHARIDE
- Contains 5 sugars that vary from species to species but common in a group and phosphate
CORE POLYSACCHARIDE
- Provide stability
CORE POLYSACCHARIDE
- Extends outward from the core polysacch
OUTER POLYSACCHARIDE
acts as an antigen bacteria
- O polysaccharides
- Comparable to TA of g+ cell wall
outer polysaccharide
- Comparable to lipotheicoic acid of g+ cell wall
Braun’s
- MULTIPLE LAYERS of peptidoglycan (60-100%)
- 20 to 80 nanometers
GRAM POSITIVE CELL WALL
- Made up of an alcohol and phosphate (Ribitol phosphate)
TEICHOIC ACID
- 2 classes of TA
o Lipoteichoic Acid
o Wall Teichoic Acid
spans the peptidog. Layer and is linked in the PLASMA MEMBRANE
o Lipoteichoic Acid
linked to PEPTIDOGLYCAN LAYER
o Wall Teichoic Acid
o CM is dynamic or changing; Flowing CM
• FLUID MOSAIC MODEL
• For semipermeability
CELL MEMBRANE
o Regulate the passage of substances – OSMOSIS; o Protection from OSMOTIC LYSIS
semipermeability
influx of water into the bacterial cell wall
Plasmoptysis
diffusion (efflux) of water from the bacterial cell
Plasmolysis
• Location for specific transport system
- Carrier mediated
- Specificity
- Carrier mediated
PERMEASE
Solute can move in and out of the cell in either direction
o Facilitated Diffusion
From a region of higher to lower solute conc
o Facilitated Diffusion
Least type of bacterial transport
o Facilitated Diffusion
Lower to higher concentrations
o Active Transport
Require energy expenditure
o Active Transport
Much common in bacteria
o Active Transport
Similar to active transport
o Group Translocation
Carrier-mediated
o Group Translocation
The solid is modified when it passes the CM
o Group Translocation
Oxidative phosphorylation results in the production of adenosine triphosphate
o Energy Generation
o Used in biosynthesis
• LOCATION OF ENZYME SYSTEMS
o Important in absorptive food acquisition
• LOCATION OF ENZYME SYSTEMS
o Formation of the components of the cell wall
• LOCATION OF ENZYME SYSTEMS
- Movement of bacterial cells in response to chemical stimulus
• CHEMOTAXIS
- Some of the proteins act as sensing bodies of the environment
• CHEMOTAXIS
chemotaxis towards the chem stimulus
o Positive Chemotaxis
chemotaxis away from the chem stimulus
o Negative Chemotaxis
Cytoplasmic invagination of the CM
o Mesosome
Facilitates the separation of chromosome
o Mesosome
Origin of the transverse septum
o Mesosome
- gen term for substances that surround the cell
• GLYCOCALYX
- viscous, gelatinous polymer
• GLYCOCALYX
- network of polysacch/polypep extending to the surface of bacteria
CAPSULE
- present in some bact
• GLYCOCALYX
ORGANIZED and FIRMLY attached to cell wall
CAPSULE
DISORGANIZED and LOOSELY attached to the cell wall
SLIME
o Capsule can be determined by
NEGATIVE STAINING
Capsule is made up of what polypeptide
GLUTAMIC ACID
4 major functions of capsule
- Protection
- Attachment
- Antigenic determinant (K-antigen)
- Source of nutrition
- helps cells in a biofilm attach to their target envi to each other
- protects the cells w/in biofilms
- facilitates communication among them
- BIOFILMS
EXTRACELULAR POLYMERIC SUBSTANCES - s. mutans
BIOFILMS
due to its viscosity, it inhibits movement of nutrients out of the cell
- Protection againt dehydration
THREAD-LIKE locomotor appendages
• FLAGELLUM
slender, rigid structures
• FLAGELLUM
20 nm across and 15 - 20nm long
• FLAGELLUM
moves in rotational manner
• FLAGELLUM
• FLAGELLUM is composed of protein called
FLAGELLIN
confers motility or locomotion
• FLAGELLUM
whip-lashing flagellum
Eukaryotic
rotational flagellum
Prokaryotic
3 FLAGELLAR ULTRASRUCTURE
- FILAMENT
- BASAL BODY
- HOOK
FLAGELLAR ULTRASRUCTURE that extends from the cell surface to the tip
FILAMENT
FLAGELLAR ULTRASRUCTURE that contains flagellin arranged in several chains that intertwine and form a helix around a hollow core
FILAMENT
FLAGELLAR ULTRASRUCTURE that is not covered by a membrane or sheath in most bacteria
FILAMENT
attached to a HOOK
FILAMENT
FLAGELLAR ULTRASRUCTURE that is embedded in the cell and is made up of series of rings
BASAL BODY
anchors the flagellum to the cell wall and plasma membrane
BASAL BODY
composed of a small central rod inserted into a series of rings
BASAL BODY
joins together the fiilament and the basal body
HOOK
FUNCTIONS OF FLAGELLUM:
1. Locomotion
- counter-clockwise
- clockwise
FUNCTIONS OF FLAGELLUM:
- “H” Antigen: derived from the term Hauch
Site of antigenic determinant
o Flagella may be distributed over the entire cell
- Peritricous
o Single flagellum at one pole
- Monotrichous
o Tuft of flagella at one pole of the cell
- Lophotrichous
o Flagella at both poles of the cell
- Amphitrichous
LONGER THAN FIMBRAE
• PILI
cell can have either one or two
• PILI
motility
• PILI
a pilus extends by addition of
pilin
makes contact with a surface or another cell
• PILI
retracts as the pilin units disassembled
• PILI
“grappling hook model”
• PILI
LOCOMOTION OF PILI
TWITCHNG MOTILITY
type of pili that fx for attachment to surfaces
- Ordinary/common
type of pili that plays a role in the pathogenecity
- Ordinary/common
o Involved in the conjugation (transfer of gene) process
- Sex pili
o Transfer mechanism for genes between bacterial cells
- Sex pili
o Involved in the formation of biofilms
• FIMBREA
o Adherence to epithelial surfaces
• FIMBREA
o Facilitating colonization of the area
• FIMBREA
incorporated in the membrane
• AXIAL FILAMENTS
“endoflagellum”
• AXIAL FILAMENTS
made up of bundles of fibers that arise from one end of the cell and spiral into the cell towards the other end of the cell
• AXIAL FILAMENTS
- beneath the outer sheath
• AXIAL FILAMENTS
confers motility to spirchetes only
• AXIAL FILAMENTS
rotation of the axial filaments produces a movement of the outer sheath that propels the spirochete in a
spiral motion
locomotion of AXIAL FILAMENTS
cork-screw motility
thick, aqueous, semi-transparent and elastic
BACTERIAL CYTOPLASM
site for metabolism and growth
BACTERIAL CYTOPLASM
BACTERIAL CYTOPLASM is consist of
CYTOSOL
semifluid mass of proteins, amino acids, sugars, nucleotides, salts, vitamins and ions dissolved in water
CYTOSOL
bacterial cytoplasm lacks these 2
- CYTOSKELETON
- CYTOPLASMIC STREAMING
spherical, elongated or dumbbell-shaped
- NUCLEIOD
occupies < 20% of cell volume
- NUCLEIOD
analogous to the nucleus of eukaryotic cells
- NUCLEIOD
area of the chromosomal material
- NUCLEIOD
single, long, continuous circular thread of DOUBLE-STRANDED DNA
NUCLEIOD of bacterial cell
attached to the plasma membrane
NUCLEIOD of bacterial cell
contains genetic info
NUCLEIOD of bacterial cell
absence of proteins (histones) and nuclear envelope
NUCLEIOD of bacterial cell
small circular double-stranded DNA
- PLASMIDS
about 1/10 of the bacterial chromosome
- PLASMIDS
extra chromosomal genetic elements
- PLASMIDS
contains only 5 to 100 gene
- PLASMIDS
not IMPORTANT for cell viability but advantage
PLASMID of bacterial cell
can be transferred and used to transfer short genes to organisms
PLASMID of bacterial cell
confers additional trait to the cell
PLASMID of bacterial cell
Additional traits of plasmids to the cell
- antibiotic resistance
- tolerance to toxic substances
- production of toxins
EXAMPLES OF PLASMIDS
- F-FACTOR
- R-FACTOR
- BACTERIOCENOGENIC FACTOR
• Ability to form sex pili
F-FACTOR
• Resistance of bacterial cells for certain antibiotics
R-FACTOR
BACTERIOCENOGENIC FACTOR produces
BACTERIOCIN
• BACTERIOCENOGENIC FACTOR - Proteins produced can inhibit the growth of other bacteria
o COLICIN
o PYOCIN
o COLICIN
o PYOCIN
o COLICIN: Escherichia coli
o PYOCIN: Pseudomonas aeruginosa
- state found in the cytoplasm
- FREE STATE
- state found incorporated with the bacterial chromosome
- INTEGRATED STATE
made up of proteins (40%) and (60%)
- RIBOSOME
- for protein synthesis
- RIBOSOME
gives the cytoplasm a granular appearance
- RIBOSOME
common to prokaryotic cells
- RIBOSOME
70 Svedberg units
- 30S - 50S
(PROKARYOTIC)
80 Svedberg units
- 40S
- 60S
(EUKARYOTIC)
the relative rate of sedimentation during ultracentrifugation
Svedberg unit
functions of ribosomes
- Site of protein synthesis
- Site of antibiotic action
- SELECTIVE TOXICITY
several kinds of reserve deposits on the cytoplasm
INCLUSION
“FOOD RESERVES”
INCLUSION
avoid an increase in osmotic pressure w/in the cell
INCLUSION
INCLUSION is made up of
CARBON and ENERGY RESERVES
COMPOSITION of INCLUSION
ORGANIC COMPOUNDS
GLYCOGEN
POLY-B-HYDROXYBUTYRATE
INORGANIC COMPOUNDS
POLYPHOSPHATES
METACHROMATIC GRANULES
reddish brown and blue
GLYCOGEN
sudan red
POLY-B-HYDROXYBUTYRATE
• Stains red with methylene blue stain
METACHROMATIC GRANULES
• Match granules
- Babes-Ernst granules
* “VOLUTIN” granules
produced in response to harsh environmental conditions
- ENDOSPORES
small, dormant (inactive), asexual spores
- ENDOSPORES
process of endospore formation within the vegetative cells
SPORULATION
process of endospores turning back to their vegetative coat
GERMINATION
GERMINATION is triggered by
damage to endospore coat
1 ENDOSPORE =
1 BACTERIAL CELL
o Endospore has resistance to:
Chemical agents Temperature changes Starvation Dehydration Radiation Desiccation
MECHANISMS OF PROTECTION BY ENDOSPORES
o THICK SPORE ENVELOPE
o DEHYDRATED STATE
o CALCIUM DIPICOLINATE
thickest layer composed of modified peptidoglycan
Spore cortex
have keratin-like proteins that contributes to hydrophobic property
Spore coat
delicate membrane made up of lipids and carbohydrates
Exosporium
Spore will only contain 15% water in the [?] making them less susceptible to heating
protoplasm
WILL REQUIRE WATER
WILL REQUIRE WATER
Responsible to the heat resistance of endospore
o CALCIUM DIPICOLINATE
CLINICALLY SIGNIFICANT SPORE-FORMERS:
o Bacillus species
o Clostridium species
Central spore
Subterminal spore
Terminal spore
o Bacillus species
Swollen sporangia Drumstick bacillus Tennis racket bacillus Tackhead bacillus Lollipop bacillus
o Clostridium species
TYPES OF SPORES:
o Central spore
o Subterminal spore
o Terminal spore with swollen sporangium
