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34 Cards in this Set

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Lec 2
- The light Microscope
- Use and limits
- used to look at cells w/ low
resolution
- resolution limit is .2
nanometers
- Bright field is used to
distinguish between density
Lec 2
- The light Microscope
- components
- Ocular
- Adds extra 10 x of
magnification
- user looks through ocular
Lec 2
- The light Microscope
- components
- Objective
- actually magnifies specimen
- vary on magnification
Lec 2
- The light Microscope
- components
- Stage
- holds slide
Lec 2
- The light Microscope
- components
- Condenser
- lens to focus light on slide
- does not assist in
mangification
Lec 2
- The light Microscope
- components
- Focusing Knobs
- adjust focus
Lec 2
- The light Microscope
- components
- Light
- light source
Lec 2
- The light Microscope
- Resolution vs.
Magnification
- reso is:
distance btwn 2 points where
2 points are still visable
- mangification is:
how big picture is
Lec 2
- The light Microscope
- Resolution vs.
Magnification
- what determines clarity
- Resolution determines clarity
Lec 2
- The light Microscope
- info about magn and reso
- Light microscope has max
magnification of 1500x
- magnification is result of
each ind. lens magnification
- w/ oil, 1000x magn and .2
micrometer resolution
Lec 2
- The light Microscope
- Bright field microscopy
- light is background
- dark is specimen
- w/out stain, microbes look
transparent
- some have pigments which can
be seen
Lec 2
- Simple Stains
- Positive
- stains actual microbe
- remains purple after stain
- shows shape of microbe and
growth (both pos and neg do)
Lec 2
- Simple Stains
- Negative
- stains background around
microbe
- shows shape of microbe and
growth (both pos and neg do)
- NO HEAT FIXING,
- use neg stain when
1 - microbe is fragile
2 - size is important (heat
shrinks)
Lec 2
- Differential Stains
- stain techniques that stain
different microbes different
colors
Lec 2
- Differential Stains
- Gram Stain
1 - Flood heat fix smear w/
crystal violet
2 - add Iodine
3 - decolorize w/ alcohol
4 - counterstain w/ safranin
Lec 2
- Differential Stains
- Gram Stain
- results
- if still violet
microbe is Gram pos
- if red
microbe is Gram neg
Lec 2
- Prokaryotic Cell envelopes
- Includes all cell membranes
and cell walls
Lec 2
- Prokaryotic Cell envelopes
- Murein
- a specific type of
peptidoglycan found only in
cell wall of bacteria
Lec 2
- Prokaryotic Cell envelopes
- Gram Pos
- Have thick Cell Wall outside
cell membrane
Lec 2
- Prokaryotic Cell envelopes
- Gram Neg
- Have a thinner cell wall
- Have (2) cell membranes
- an outer membrane
- and the internal cell mem.
Lec 2
- Prokaryotic Cell envelopes
- Bacterial Cell membranes
- Fatty acids block most
molecules
- Permeable to H20
- Active transport needed for
other molecules
Lec 2
- Prokaryotic Cell envelopes
- Archea Cell Membrane
- NO fatty acids
- uses phytanyl for bilayer
- uses biphytanyl for unilayer
Lec 2
- Prokaryotic Cell envelopes
- Archea Cell Membrane
- Bilayer Cell mem.
- Uses Phytanyl with C20 chains
- Creates a bilayer cell mem.
- links 4 Isoprenes together
- Unstable at high temp
Lec 2
- Prokaryotic Cell envelopes
- Archea Cell Membrane
- Unilayer Cell Mem.
- Uses Biphytanly w/ C40 chains
- creates a unilayer cell mem.
- Stable at high temp
Lec 2
- Prokaryotic Cell envelopes
- Murein composition in
Bacterial Cell walls
- Glycan chains of Alt. NAG -
NAM
- NAMs have short peptide chains
that are cross linked
- Peptide chains give rigidity
Lec 2
- Prokaryotic Cell envelopes
- Murein composition in
Bacterial Cell walls
- Lysozyme action
- found in tears and such
- lysozyme attacks murein at
NAG-NAM linkage
Lec 2
- Prokaryotic Cell envelopes
- Murein composition in
Bacterial Cell walls
- Gram Pos Comp
- Cross links occur between
Lys and D-Ala
Lec 2
- Prokaryotic Cell envelopes
- Murein composition in
Bacterial Cell walls
- Gram neg Comp
- Cross links occur between
Dap and D-Ala
Lec 2
- Prokaryotic Cell envelopes
- Techoic Acid and Gram Pos
cell wall
- In gram pos cell walls, they
have techoic acids
- embedded in cell wall and
stick out
- repeating glycerol and
ribitol units linked via
phosphodiester bonds
- allow for identification of
microbes
Lec 2
- Prokaryotic Cell envelopes
- Gram Neg outer cell mem
and(LPS)
- Has Lypopolysaccharides (LPS)
- 3 major parts
1 -Lipid A - causes fever
and shock
2 -Core - conserved sugar
form same for all gram -
3 -AgO - highly variable and
immunogenic
Lec 2
- Variations on Cell envelopes
- all bacteria susceptable to lysozyme at NAG-NAM linkage
- Mycoplasma and thermoplasma
have no cell wall
- Mycobacterium have wax in cell wall
Lec 2
- Mycobacterium
- Characteristics and
special staining
- Have Wax (mycolic acid) in
cell wall
- causes turbuculosis and
leprossy
- needs ACID FAST STAIN to be
seen
Lec 2
- S Layer
- Outermost part of cell
envelope
- made of crystalline or glyco
protein structure
(honeycomb)
- some archaens have s-layer
instead of cell wall
- also found in gram pos
Lec 2
- S Layer
- purpose
- No one knows
- does not add rigidity
- maybe protection from viruses
- useful for nanotechnology