Flashcards in Introduction to Microbiology Deck (55)
Name two advantages of a bacterial cell being small.
Increases rate of nutrients and waste in and out/ Higher growth rate for faster adaptation.
What are the typical structures of a prokaryotic cell?
Cell wall (plus flagella, pilli), Cell membranes, Cytoplasm, Nuclear region.
What is in the cytoplasm?
Enzymes, regulatory proteins and protein synthesis machinery
What are the phospholipid membrane proteins functions?
Transport of nutrients, energy generation, secretion, synthesis of peptidoglycan, regulatory proteins
What are the two groups bacteria can be divided into based upon cell walls?
Gram- positive or gram- negative
What is meant by gram- positive?
The bacteria has retained the crystal violet-iodine complex
What is the difference in cell walls of gram positive and negative?
Gram positive- thick peptidoglycan layer, 1 cell membrane. Gram negative- inner and outer membrane and thin peptidoglycan layer
Name an example of gram- positive/negative bacteria
+ Streptococcus spp
What is peptidoglycan made from?
polysaccharide backbone of two sugar derivatives linked by peptide bridge. N-acetylglucosamine/ N-acetylmuramic acid.
Why is acid-fast staining used?
Acid fast microorganisms do not stain well
What are exampled of acid fast organisms?
M.Bovis and M.Tuberculosis
Why do acid fast bacteria not stain well?
Mycolic acid and lipids in the cell wall which interfere.
What is a mycoplasma?
Bacteria with no cell wall
What does a mycoplasma require externally?
Cholesterol, amino acids and fatty acids
What is the space between two membranes in a gram negative bacteria called?
Periplasm- where the peptidoglycan is
What is lipopolysaccharide?
an endotoxin which causes fever (pyrogenic) on the very outer layer of a gram negative bacteria
What are the three parts to a lipopolysaccharide?
O-antigen, core polysaccharide, Lipid A
What are cell surface structures?
Flagella, fimbriae and pilli, capsules.
What is the function of a flagella?
Motility of the cell
What are the function of fimbriea and pilli?
The hair like structures which attach to surfaces and for sexual reproduction by transferring plasmids
What is a capsule?
a discrete layer of polysaccharides outside the cell
What is a slime layer?
A less discrete structure which embeds the cell for attachment
What are phenotypic ways of classification?
Staining, cell morphology- cocci, oxygen requirements, culture properties, colony morphology
What are genetic ways of classification?
DNA based, rRNA sequences
Why can bacteria be incorrectly classified?
Horizontal gene transfer
What is mycology?
The study of fungi
What is a disease called caused by a fungus?
Are fungi eukaryotes or prokaryotes?
Are fungi aerobes?
All fungi are aerobes some are strict aerobes