Lesson 2.1 Phenetic and Phenotypic Classification Flashcards
This system suceeded in bringing order to biological diversity and clarify the morphological structures .
Phenetic or Phenotypic classification
Refers to the size and shape of the bacteria
Morphology
What are the common shapes of bacteria
Cocci- spherical
Bacili- rod
Spirilla- spiral
Vibrios- comma
Spirochaetes- corkscrew-shaped
Staining technique that is used to distinguish bacteria based on their cell wall structure
Gram staining
What are the two outcomes of gram staning
Gram positive- thick peptidoglycan would stain purple
Gram-negative- thin peptidoglycan, would stain pink. have outer membrane
What are the process of gram staining
Crystal violet - 60 sec
Iodine- 60 sec
Ethyl Alcohol - 5-10 sec
Safranin - 45 sec
Function of cell wall
protect against cell lysis and confer shape and rigidity
____ and ____ are antibiotics that targets the bacterial cell wall synthesis.
Penicillin and cephalosporin
What is the repeating unit of peptidoglycan is called _______.
In some bacteria, other amino acids are present such as _______
glycan tetrapeptide
Cross-linkers
It is a rigid polysaccharide and confers structural strength on the cell
Peptidoglycan
Alternating repeats of two modified
glucose residues
N-acetylglucosamine (first hydroxide)
N-acetylmuramic acid (fourth hydroxide)
Difference in peptidoglycan between E.coli and Staphylococcus aureus
Gram negative and E.coli: no interbridge
S.aureus:
Which bond confers strength on peptidoglycan in X-direction____
and ____ in Y-direction
X- glycosidic bond
Y- peptide bond
Gram-negative bacteria cross link
Gram- positive bacteria cross link
Gram-negative: DAP Diaminopimelic acid from the glycan strand to another carbonyl of d-alanine to the adjacent glycan
Gram-positive: inter bridge, five glycines
What are some components found only in gram-positive
Teichoic acid and lipoteichoic acids
The structure of teichoic acid is consists of repeating ____ unit
ribitol
Gram-positive bacteria has ___ of peptidoglycan
90%
Gram-positive bacteria can form ____ about ____ wide consisting of several glycan strands
cables, 50 nm
______ have proteins that are
involved with the peptidoglycan along with the cytoplasmic membrane
Gram-positive
are composed of glycerol
phosphate or ribitol phosphate with
attached molecules of glucose or
d-alanine (or both).
Teichoic acid
Lipoteichoic acids are anchored in _________
Teichoic acids are covalently bonded to _________
Lipoteichoic acids are anchored in the cell membrane via glycolipids
Teichoic acid is bonded to membrane lipids and not peptidoglycan
Location of teichoic and lipoteichoic acid
teichoic- external
lipoteichoic- cytoplasmic membrane
The stucture found only in gram-negative bacteria
LPS- the outer membrane
The second lipid bilayer, containing lipid
and polysaccharide, is linked to form this complex
lipopolysaccharide
It acts as an effective barrier against many substances such as antibiotics
lipopolysaccharide
The important biological activity of LPS is ____ and found in the following:
toxicity; endotoxins
Salmonella, shigella and e.coli
LPS is composed of two polysaccharides
Core polysaccharide
O-specific polysaccharide
Lipid A
Which structure of the LPS contains endotoxin complex
Lipid A
Composition of LPS that has
components present in sugar form. It possesses a chain of KDO that stands as keto deoxy octanoate relating to Lipid A
core polysaccharide
Another component of LPS that anchors the outer membrane and peptidoglycan
Braun lipoprotein
