LESSON 7: BACTERIAL MORPHOLOGY AND FINE STRUCTURE Flashcards
The size of most bacteria ranges from 0.2 μm (micrometer) to 2.0 μm
in diameter and from 2.0 μm to 8.0 μm. Bacteria come
usually ound 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
Cocci :
a. Monococcus:
b. Diplococcus:
c. Streptococcus:
d. Tetracoccus:
e. Staphylococcus:
f. Sarcina:
: represented by single, discrete round cell.
Monococcus
: the cell of the 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 group of four.
Tetracoccus
: here the cells divided into three planes forming a
structured like bunches of grapes giving and irregular configuration.
Staphylococcus
: here the cells divided into three planes forming a
structured like bunches of grapes giving and 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
F. Sarcina
: these are rod shaped or cylindrical bacteria which either remain singly or
in pairs.
Bacilli
Bacilli 3
a. Diplobacilli:
b. Streptobacilli:
c. Coccobacilli:
appear in pairs after cell division
Diplobacilli
occurs in chain after cell division
Streptobacilli
: oval shaped similar
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
BACTERIAL Structure
BACTERIAL Structure
: (meaning sugar coat) are viscous substances that surrounds the cell
composed of polysaccharide, polypeptide or both
Glycocalyx
Functions
: (1) enables bacteria
to survive by attaching to surfaces, example: Streptococcus mutans attaches tothe surface of the teeth and cause dental carries,
(2) bacterial source of energy
when supply is low, and
(3) protection to hosts cell by attaching to surface hence
preventing the movements of nutrients out of cell during dehydration.
Glycocalyx
It come in two forms:
– 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 hosts cells,
(a.) capsule form
form – the substance in unorganized and is loosely attached to the cell wall
b.) slime layer