Bacterial Fine Structures, Functions and Synthesis Flashcards
General term for any network of polysaccharide containing material extending outside of the cell.
Glycocalyx
Closely associated with cells and does not wash off easily
Capsule
Zone of more diffuse, unorganized material and is easily washed away.
Slime layer
It constitutes 50-90% of the dry weight of the wall and are thicker and stronger than those gram-negative bacteria.
Periplasm or Peptidoglycan
It consists primarily of an alcohol and phosphate.
Teichoic acid
Covalently linked to peptidogylcan
Wall teichoic acid
Covalently linked to membrane glycolipid and concentrated in mesosomes.
Membrane teichoic acid/Lipoteichoic acid
It is a bi-layered structure and external to the peptidoglycan
Outer membrane
Murein lipoproteins seemingly attach to the peptidoglycan by their protein portion and to the outer membrane by their lipid component.
Lipoprotein
A structural component that is unique to the gram negative outer membrane
Lipopolysaccharide
Composed of a overlapping lattice of 2 sugars that are cross-linked by amino acid bridges.
Cell wall peptidoglycan synthesis
NAM, AMA, or MurNAc
only found in the CELL WALLS of bacteria
- It is a typical unit membrane, composed of phospholipids and proteins.
- It can only be seen with electron microscope
Cell membrane
FUNCTIONS OF THE CELL MEMBRANE
- Semipermeable membrane
- Housing enzymes
- Housing many sensory and chemotaxis proteins
- Generation of chemical energy
- Cell motility
- Mediation of chromosomal segregation during replication
- Slender threadlike portion, long, hollow, helical filaments
- It originates in the bacterial protoplasm and is extruded through the cell wall
Flagella
Protein subunit of the flagellum that carries H-antigen specificity.
Flagellin
Longest and most obvious portion which extend from the cell surface to the tip.
Filament
It is a short, curved segment which links the filament to its basal body and functions as universal joint between the basal body and the filament.
Hook
It is embedded in the cell wall.
Basal body
4 rings connected to a central rod.
L, P, S, and M
Single polar flagellum
Monotrichous
Example of Monotrichous?
Cholera vibrio
Single flagellum at both ends
Amphitrichous
Example of Amphitrichous?
Alcaligenes faecalis
Tuft of flagella at one or both ends?
Lophotrichous
Flagella surrounding the cell
Peritrichous
Example of Lophotrichous?
Spirilla
Example of Peritrichous?
Typhoid bacili
During flagellar synthesis, when the flagellum is cut off it will regenerate until reaches a maximum length. As this occurs the growth is from the base.
T OR F
FALSE
The growth is NOT from the BASE, but from the TIP
- Short, fine, hair like surface appendages
- Shorter and thinner than flagella
- They occur in non-motile, as well as in motile strains.
Pili or Fimbria
Structural subunits of pili or fimbria?
Pilins
Fimbriae do not function in motility but are thought to be important in attachment to surfaces or at least in cells sticking together.
T or F
TRUE
Fimbriae function as organs of adhesions that allow attachment of a bacterial cell to other cells or surfaces.
Ordinary (common) pili
- Longer and fewer in number than other fimbriae
- Genetically determined by sex factors or conjugative plasmid and appear to be involved in the transfer of DNA during conjugation.
Sex pili
Viscous watery solution or soft gel cell material bounded by the cytoplasmic membrane
Cytoplasm
3 areas in cytoplasm?
- Cytoplasmic area - granular
- Chromatinic area
- Fluid portion - contain inclusion and vacuoles
- Small, electron-dense particles in the cytoplasmic region
- It is the location for all bacterial protein synthesis
Ribosomes
Most genes encode proteins here.
mRNA
Also central to translation and provide the site at which translation occurs.
rRNA
It transfers the genetic information carried in the mRNA into functional proteins.
tRNA
- These are not permanent or essential structures, and may be absent under certain conditions of growth.
- It is usually for storage and reduce osmotic pressure by tying up molecules in particulate form.
Intracytoplasmic inclusions
It function as storage for reservoirs for phosphate, highly refractive, strongly basophilic bodies consisting of polymetaphosphate.
Metachromatic or volutin granules
The nuclear DNA is associated with BASIC PROTEIN.
T OR F
False
DNA IS NOT ASSOCIATED WITH BASIC PROTEIN
Uses of spores:
- Importance in food, industrial and medical technology
- Sterilization control
- Research
It is the spore protoplast containing the normal cell structures but is metabolically inactive.
Core
- Innermost layer surrounding the inner spore membrane
- It contains normal peptidoglycan
Spore wall
Thickest layer of the spore envelope.
Cortex
Enclosed by fairly thick spore coat.
Spore coat
Additional rather loose covering that have distinctive ridges and grooves.
Exosporium
Newly replicated bacterial chromosome and a small portion of cytoplasm are isolated by an ingrowth of the plasma membrane called?
Spore septum
Double layered membrane that surrounds the chromosome and cytoplasm.
Forespore
Finally exosporium disintegrates and the endospore is freed.
Free endospore
