Bacterial Cell Morphology Flashcards
Describe bacillus (bacilli)
Rod-shaped
Describe coccus (cocci)
Spherical
Describe spirillum (spirilla)
Spiral
Describe coccobacillus
Rod-shaped with round ends, mistaken for coccus
Describe spirochete
Spiral shaped cell with unique motility
Describe pleomorphic
Varies in shape
What type of cell wall has a thick peptidoglycan layer surrounding the cell membrane? (also what layer is this?)
Gram +
Phospholipid bilayer
Which cell wall stains purple?
Gram +
Which cell wall contains teichoic acid, and what does it create?
Gram +
Negative charge
Which cell wall has a thin peptidoglycan layer?
Gram -
What surrounds the peptidoglycan layer on gram - ?
Outer membrane (OM)
What is embedded in the OM of Gram - cell walls? And what is it composed of?
Lipopolysaccrahide (LPS)
Lipid A and O specific polysaccharide = endotoxin
Which portion of LPS is toxic?
Lipid A
Which cell wall type stains pink?
Gram -
Which cell wall had a high lipid content that does not readily take up stain?
Acid-fast
What does Acid-fast require to stain?
Unique dyes and heat
In Which genus are all species acid-fast?
Mycobacterium
Describe the membrane of cells that lack a cell wall
High sterol content = rigidity of cell
What is the phospholipid bilayer (a fluid structure containing proteins moving in bilayer) known as?
Fluid mosaic model.
Which kind of selective permeability is rarely used in bacteria?
Facilitated diffusion
Various transport proteins used to move substances across membranes is what type of selective permeability?
Active transport (requires energy)
Where does oxidative phosphorylation take place?
Cell membrane
What kind of mechanisms are used by the cell membrane?
Secretory and excretory
What kind of enzymes are located in the cell membrane?
Enzymes used in DNA replication
What do the proteins that extrude from the surface of the cell membrane do?
They act as receptors in cell metabolism and communication
What is a mesosome?
Invaginations of the cytoplasmic membrane that can form into vesicles , possible role in cell division
What is the periplasmic space?
Space between the inner and outer membranes in Gram negative cells.
What structure is a region of bacterial cell containing DNA (generally circular)?
Nucleoid
What structure is a small extrachromosomal DNA, autonomous replication?
Plasmid
What structure is an organelle composed of ribosomal RNA and protein?
Ribosome
What structure is: accumulations of high molecular weight polymers, also called inclusion bodies, granular inclusions?
Storage granules
What are the functions of flagella
Motility
Virulence factor
What are the functions of pili (fimbriae)?
Adherence factors
Sex pili transfer plasmids
Virulence factor
What are the functions of the capsule (slime layer)=glycocalyx?
Protective wall around some G+ and G-
Virulence factor - impedes phagocytosis
Describe endospores
Unique dormant cell type produced by some bacteria in response to adverse conditions
What is sporulation?
Endospore formation
Is an endospore reproductive?
No.
One vegetative cell = one endospore
What are endospores composed of!
Modified peptidoglycan and dipicolinic acid
