CHAPTER 2: Lesson 7: Bacterial Morphology and Fine Structure Flashcards
The size of most bacteria ranges from ________ to ________ and from _______ to ________.
0.2 μm (micrometer) to 2.0 μm in diameter
2.0 μm to 8.0 μm
Several shapes of bacteria
Cocci
Bacilli
Vibro
Spirilla
Spirochete
Usually round but can either be oval,
elongated, spherical or elliptical shape. Either they may remain as a single cell or
may aggregate together for various configurations.
Cocci: (singular: coccus meaning berries)
6 various configurations of Cocci
a. Monococcus
b. Diplococcus
c. Streptococcus
d. Tetracoccus
e. Staphylococcus
f. Sarcina
Represented by single, discrete round cell
Monococcus
The cell of this bacteria divides but the cells remain attached to each other.
Diplococcus
Here the cells divide repeatedly in one plane to form chain
of cells
Streptococcus
This consists of four round cells, which divide in two planes at
right angles to one another and remain in a group of four
Tetracoccus
Here the cells are divided into three planes forming a
structured like bunches of grapes giving an irregular configuration
Staphylococcus
These cells divide in three planes but they form a cube like
configuration consisting of eight or sixteen cells but they have a regular
shape.
Sarcina
These are rod shaped or cylindrical bacteria which either remain singly or
in pairs.
Bacilli
appear in pairs after cell division
Diplobacilli
occurs in chain after cell division
Streptobacilli
Oval shaped similar to cocci
Coccobacilli
3 type of Bacilli
Diplobacilli
Streptobacilli
Coccobacilli
curved, comma shaped bacteria and represented by a single genus
Vibro
Spiral or spring like with multiple curvature and terminal flagella with
fairly rigid bodies.
Spirilla
Helical and flexible which move by means of axial filaments
resembling flagella but contained within an external sheath.
Spirochete
Structures external to the cell wall
Glycocalyx
Flagella
Axial filaments
Fimbriae
Pili
These are viscous substances that surround the cell
composed of polysaccharide, polypeptide or both
Glycocalyx: (meaning sugar coat)
Functions of Glycocalyx
(1) enables bacteria
to survive by attaching to surfaces, example: Streptococcus mutans attaches to
the surface of the teeth and cause dental carries,
(2) bacterial source of energy
when supply is low, and
(3) protection to host cell by attaching to surface hence
preventing the movements of nutrients out of the cell during dehydration.
Two forms of Glycocalyx
a. capsule form
b. slime layer
form
The substance is organized, is firmly attached to
the cell wall, and clinically contributes to the virulence (ability to cause disease) of
bacteria due to its capacity to evade phagocytosis by host cells.
capsule form
The substance is unorganized and is loosely attached to the cell wall.
slime layer form
These are long filamentous appendages
that propels bacteria.
Flagella: (singular: flagellum, meaning whip)
Three basic parts of Flagella
(1) filament
(2) hook
(3)
basal body
Long outermost part that
contains flagellin arranged in helix.
filament
where filament is attached to
hook
It anchors the flagellum to the cell wall and plasma membrane. The
flagella move by rotating from this part either in clockwise or
counterclockwise direction.
basal body
The movement of the basal body is termed as _________.
motility
Motility can be
presented in different patterns: what are these patterns?
(a) run or swim
(b) tumbles
(c) swarm
bacterium moves in one
direction
run or swim
periodic abrupt or random interruptions to run or swim
tumbles
rapid wavelike movement
swarm
It also called endoflagella present in Spirochetes like Borrelia
burgdorferi that causes Lyme disease. These are actually bundled fibrils
that arises at one end of Spirochetes and spirals around it. When these filaments
rotate it causes the Spirochetes to a spiral motion.
Axial filaments
It is a type of protein called pilin. It has numerous hair like appendages
that surrounds the bacterium and helps to attach to hosts surfaces
Fimbriae
It is another type of the protein pilin but is only presented in one or two per
bacterium.
Pili
It helps bacterial cells to prepare DNA transfer from one cell to
another.
Pili
It is a semi rigid structure that protects the interior of the cell
from the outside environment.
Bacterial cell wall
Functions of bacterial cell wall
(1) prevents rupture of the cell,
(2)
maintain the shape of the cell,
(3) anchors flagella,
(4) contributes to the virulence of the
bacteria,
(5) site of action of some antibiotics, and
(6) the chemical composition
of cells is used to differentiate types of bacteria
The bacterial cell wall is primarily composed of network of ___________.
peptidoglycan
(also called murein)
Have multiple layers of peptidoglycan in its cell wall for a thick
rigid structure.
Gram positive bacteria
Gram positive bacteria contains __________ which provide the antigenic capacity of
the bacteria making it possible to identify it upon laboratory tests.
teichoic acids
The cell wall of this bacteria has a thin layer of peptidoglycan
making it very susceptible to mechanical breakage or environmental degradation.
Gram negative bacteria
The cell wall (outer portion) of a Gram negative bacteria are composed of what?
lipopolysaccharide (LPS, also called endotoxin)
lipoproteins
phospholipids
Functions of the outer portion of a bacterial Cell Wall
(1) evades
phagocytosis and cell lysis,
(2) barrier to antibiotics and other enzymes,
(3) passage of molecules thru porin channels.
Functions of Lipopolysaccharide (LPS)
(1) provides
antigenic capacity of the bacteria
(2) causes physiological effects when
present in the bloodstream (toxicity, fever, sepsis, shock, or death)
What are the bacteria that is composed of higher percentage of mycolic acid
in their cell walls than peptidoglycan which
prevents reaction to Gram stains?
Mycobacterium sp
Nocardia sp
Bacteria that are composed of high mycolic acid can be stained with a _________
which resist removal with acid alcohol thus called __________.
carbolfuchsin
acid-fast bacteria
What do you call those having no cell wall or with very little wall material. Give 1 example of a bacteria.
atypical cell walls (Mycoplasma sp.)
These chemicals can also cause damage, or interfere with the
synthesis of cell walls by cell lysis.
lysozyme
Structures internal to the cell wall
Plasma membrane
Cytoplasm
Nuclear area
Ribosomes
Inclusions
Endospores
Underlying the cell wall is a thin layer of this which is
composed mainly of phospholipids arranged in two rows called lipid bilayer. The
outer surfaces of the lipid bilayer (polar heads) are hydrophilic or water-loving,
while the inside of the bilayer (nonpolar tails) are hydrophobic or water-fearing.
Plasma membrane
Underlying the cell wall is a thin layer of this which is
composed mainly of phospholipids arranged in two rows called ___________.
lipid bilayer
The
outer surfaces of the lipid bilayer (polar heads) are __________,
while the inside of the bilayer (nonpolar tails) are _________.
hydrophilic or water-loving
hydrophobic or water-fearing
Functions of a Plasma Membrane
(1) entry/exit of substances in cells by selective permeability,
(2)
protect and lubricate the cell,
(3) cell-to-cell interactions
(4) breakdown of
nutrients and energy production.
The movement of materials/substances across the membrane can be either be what?
Passive Processes or Active Processes
Passive Processes include what?
Simple diffusion
Facilitated Diffusion
Osmosis
movement of molecules from high concentration to low concentration
Simple diffusion
Same with simple diffusion but substances are transported
across the membrane via transporter.
Facilitated diffusion
Movement of a solvent
molecule (water) from high concentration to low concentration via a selectively
permeable membrane
Osmosis
Types of Active Processes
Active Transport
Group Translocation
The cell
uses energy to transport a substance from lower to higher concentration without
altering the substance
Active transport
A special type of active that
alters the substance being transported across a membrane.
group translocation
The substance inside the plasma membrane composed mainly of
water and other substances like proteins, carbohydrates or lipids.
Cytoplasm
It is located in the cytoplasm of a bacterial cell
contains double-stranded DNA each for the bacterial chromosome and plasmid.
Nuclear area also called nucleoid
It contains the genetic information of the cell.
Bacterial chromosome
It carry genes associated to antibiotic resistance, toxin production or enzyme
synthesis. It is important in gene manipulation of bacteria.
plasmid
It is present in both prokaryotic and eukaryotic cells and serve as sites
for protein synthesis. The number of this is proportional to the rate of
protein production.
Ribosomes
Ribosomes have 2 subunits: ________ (small and contains one
molecule of ribosomal [rRNA] in bacteria), and ________ (larger and contains
two molecules of rRNA in bacteria). Ribosomes in bacteria are called _____________.
30S
50S subunit
70S
ribosomes
These are reserve deposits of (1) metachromatic granules (used in
ATP synthesis), (2) polysaccharide granules, (3) lipid inclusions, (4) sulfur
granules (energy reserve), (5) carboxysomes (for carbon dioxide fixation), (6) gas
vacuoles (maintain buoyancy), and (7) magnetosomes: are iron oxide that acts
like magnet to move until attachment site.
Inclusions
A reserve deposit that is used in
ATP synthesis.
metachromatic granules
A reserve deposit used as energy reserve
sulfur
granules
Reserve deposit used for carbon dioxide fixation.
carboxysomes
A reserve deposit that maintains buoyancy.
gas
vacuoles
These are iron oxide that acts
like a magnet to move until the attachment site.
magnetosomes
These are specialized resting cells formed internal the cell
membrane when a bacterial cell goes into vegetative state (active cell that
undergoes metabolism) in a process called sporulation. These
are released when bacterial (parent) cell is degraded. It is capable of resistance
to harsh chemicals, extreme environmental condition, and radiation.
Endospores
It can remain dormant for a thousand years and can return to vegetative
state by germination when its coat is triggered either by physical or
chemical damage.
endospore
The process when a bacterial cell goes into vegetative state (active cell that
undergoes metabolism).
Sporulation
