Topic 5 Flashcards
What microbe does not contain a cell wall?
mollicutes/mycoplasmas
Give an example of a mollicute.
mycoplasma pneumonia
What sugars make up the peptidoglycan in bacteria?
N-acetyl glucosamine (G/NAG) and N-acetyl muramic acid (M/NAM)
What is a lysozyme?
an enzyme that digests the bond between the sugars in the PG
Describe the gram-positive bacterial cell wall.
Has a thick, 4-layered PG and lipteichoic acid and teichoic acids to add strength
Give 2 examples of G+ bacteria?
Bacillus cereus and staphylococcus aureus
What is the result of gram staining mycobacterium? What stain works best?
They are gram-variable due to the very thick PG and high [lipid];
Ziehl-Nielsen acid fast stain
What is unique features of the cell wall of mycobacterium?
Thick PG with arabinogalatan layer and mycolic acids
Describe the Gram negative bacterial cell wall.
Has one layer of peptidoglycan in the periplasm located between an inner and outer membrane, the outer membrane contains lipopolysaccharides
What are lipopolysaccharides?
A lipid with 3 distinct regions:
Lipid A - a toxin when released from lysed cells, O antigen - induces antibody response, and polysaccharide core
Give two examples of Gram negative bacteria.
E. coli and haemophilus influenza
Describe the 3 genes that control bacterial cytoskeleton shape.
FtsZ - forms a Z-ring in spherical cells
CreB - forms crescent shaped bacteria
MreB - forms a coil inside rod shaped bacteria
What is the S-layer?
A flexible layer of glycoproteins in a crystallin that are found on some G- and G+ bacteria
What are capsules?
A mucus layers surrounding cell envelop in some G- and G+ bacteria
What are thylakoids?
sheets packed with photosynthetic pigments that maximize photosynthesis only in G- phototrophs
