Cell Surface Structures
Could a bacterial cell dispense with a cell wall if it had a capsule? Why or why not?
Capsule: organized layer in a tight matrix that excludes small particles such as India ink;
stick firmly to cell wall (can even coval
What are the 3 domains of life? Which families belong in each? Comment on general relation
Bacteria and Archaea (prokaryotic cells) and Eukarya (eukaryotes) diverged from common
ancestor LUCA (last universal common ancestor)
Studied these 2 polysaccharide layers in Salmonella
O-specific polysaccharide contains: galactose, glucose, rhamnose, and mannose,
dideoxyhexoses (abequose, colitose, paratose, or tyvelose) connected in 4 or 5 membered
branched sequences o
Describe the diversity of peptidoglycan.
Only in Bacteria (not Archaea or Eukarya)
Unusual to have 2 D-stereoisomers
Diversity in peptide cross-links and interbridge
Glycan portion is constant but tetrapeptide can have variation in lysine-DA
Cell Wall of Bacteria: Peptidoglycan
Make some general comments on cell walls. What is their purpose? What are the two main
types and how do they differ?
The cytoplasm contains a high concentration of dissolved solutes because of transport
Comment on the crucial difference between Bacteria and Archaea with
respect to their cell membranes.
Bacteria are strengthened by molecules called
hopanoids (rigid planar molecules similar to sterols that
strengthen the membrane of eukaryotic ce
Explain the different ways that a cells shape can be described
: the cells shape
morphology on its
Bacteria vs. an
arose to maximize
species (ex. sma
Which phyla are present in the domain Bacteria? Comment where appropriate in each.
cteria: the largest phylum of Bacteria many of which are
o Chemoorganotrophs: E. Coli (model
o Several phototrophic and
What were Kochs Postulates? Why did he develop them and what did they help him
He developed them when he was working on Anthrax- a disease of cattle and occasionally
Trying to determine whether a certain bacterium called Bacil
Name and comment on 5 major areas of applied microbiology.
o Benefits from cycling of nutrients by microorganisms
Bacteria accumulate in the root nodules of alfalfa plants and "fix nitrogen",
which means they turn nitrogen into am
Chapter 1: Microorganisms and Microbiology
Why Study Microbiology?
What is microbiology? How old is this field? What did this study give rise to?
Microbiology: study of microorganisms (especially bacteria- a very large group of small
cells) and how they