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
