Microbial world - Classification & Structure of Bacteria Flashcards
It is the study of microorganisms, a large and diverse group of microscopic organisms that exist as single cells or cell clusters.
Microbiology
Group of organisms: contain multiple genera and consists of organisms with a common attribute.
Family
Plural of genus:
genera
Contains different species that have several important features in common.
Genus
Defined as a collection of bacterial strains that share common physiologic and genetic features and differ notably from other microbial species.
Species
(readily observable physical and functional features of an organism expressed by its genotype).
Phenotype
Genetic makeup of an organism, or combinations of forms of one or a few genes under scrutiny in an organism’s genome).
Genotype
It is the naming of microorganisms according to established rules and guidelines set forth in the International Code of Nomenclature of Bacteria (ICNB) or the Bacteriological Code (BC).
Nomenclature
ICNB means
International Code of Nomenclature Bacteria
Bacteria are classified as?
prokaryotes
the outermost structure.
Cell envelope
It acts as a barrier to hydrophobic compounds and harmful substances.
Outer membrane
Control the passage of nutrients and other solutes, including antibiotics, through the outer membrane.
Porins
It provides attachment sites that enhance attachment to host cells.
Outer membrane
Also referred to as the peptidoglycan, or murein layer.
Cell wall
Disaccharides: N-acetylglucosamine and N acetylmuramic acid
Cell wall
N-acetylglucosamine and N-acetylmuramic acid
Disaccharides
Diaminopimelic acid: It is never found in the cell walls of Archaea or eukaryotes
Cell wall
It is never found in the cell walls of Archaea or eukaryotes.
Diaminopimelic acid
two major types of cell walls:
- gram positive
- gram negative
very thick protective peptidoglycan (murein) layer.
[cell wall]
Gram-positive cell wall
the inner peptidoglycan layer is much thinner than in gram-positive cell walls.
[cell wall]
Gram-negative cell wall
Have diaminopimelic acid in their cell wall.
[cell wall]
Gram-negative cell wall
contains proteins, phospholipids, and lipopolysaccharide (LPS).
[cell wall]
Gram-negative cell wall
Other components are teichoic acid and lipoteichoic acid which are unique to the gram-positive cell wall.
[cell wall]
Gram-positive cell wall
LPS contains three regions:
- antigenic O-specific polysaccharide
- core polysaccharide
- inner lipid A (aka endotoxin)
It is responsible for producing fever and shock conditions in patients infected with gram negative bacteria.
Lipid A moeity
Cover the bacterial surface and exclude hydrophobic compounds.
O antigen
The most abundant protein of gram-negative cells.
Lipoprotein
Its function is to stabilize the outer membrane and anchor it to the peptidoglycan layer.
Lipoprotein
Found only in gram negative bacteria.
Periplasmic space
Present in both gram-positive and gram negative bacteria and is the deepest layer of the cell envelope.
Cytoplasmic (inner) membrane
