why is blue light preferable?
blue has the short wavelengths and it optimizes resolution
- removable lens at top of body (binocular) tube:usually 10x
- magnification
eyepiece (ocular)
- main cylindrical part
- holds oculars, conducts light from specimen
binocular (body) tube
- movable, usually circular plate at bottom of body tube
- holds objectives
nosepiece
- objective lens, usually 4x (red)
- magnification
scanning objective
- objective lens, usually 10x (yellow)
- magnification
low power objective
- objective lens, usually 40x (blue)
- magnification
high (dry) power pbjective
- objective lens usually 100x (white)
- magnification
oil immersion objective
- lens system located below stage opening
- concentrates and directs light through specimen
condenser
- behind condenser, below stage
- adjusts height of condenser
condenser adjustment knob
- platform upon which slides are placed
- specimen support
stage
- right side, below stage and in front of adjustment knobs
- move the mechanical stage forward/backward and side to side
coaxial stage controls
- located below stage with condenser unit, controlled with lever
- regulates brightness/resolution vs contrast/range of focus
condenser aperture (iris) diaphragm
- back of scopes, below stage
- used for preliminary and course focusing
course focus adjust knob
- smaller knob centered on course adjustment knob
- for final or fine focusing
fine focus adjustment knob
- set in base of scope
- light source
lamp
- on right side of scope
- for adjusting the light intensity from the lamp
voltage control knob (rheostat)
- heavy, bottom portion on which instrument rests
- microscope support
base
size of rbc
10μm
resolving/resolution power of human eye and light microscope
human eye- 0.1mm
light microscope- 0.2 μm
steps to focus a microscope
start with scanning objective
- increase magnification 100x
- focus towards you
- which ever focuses first is at bottom on slide
which is bigger: rbc or wbc?
wbc
image seen through a compound light microscope is _______ and ____
upside down and backwards
name the colored threads from top to bottom
yellow, red, blue
three ways light hitting the specimen is adjusted
condenser, voltage control knob, iris diaphragm
why is it important to have whatever you are observing centered, when you move to a lens with a higher magnification?
to keep specimen in the working field
how does the working distance differ between the scanning lens and the oil immersion lens?
- scanning lens has a gap between objective lens and slide
- oil immersion has a drop of oil that adheres to the objective lens and cannot move once they are touching
the objective lenses are attached to the
eyepiece
a microscope built with only one eye piece is known as a ___________ microscope
binocular
Abbe equation for resolution
d= 0.5λ/n sin Θ
Ideally a microscope should be ___________, hat is, the image should remain in focus when objective lenses are changed.
parfocal
- eukaryotic
- unicellular
- non photosynthetic
- no cell wall
protozoa
protozoans are primarily based on their means of
locomotion/motility
four groups of protozoa’s we observed in lab
ciliates (Cilliophora), flagellates (Mastigophora), amoeba (Sarcodina), and nonmotile protozoa (Sporozoa)
staining techniques are helpful for
increasing contract between mo’s, the environment and/or structures within mo’s
dye that colors the food vacuoles of protozoa, facilitating observations of these organisms
vitachrome
microscopes that are useful for observing clear images of unpigmented living cells
dark-field and phase contrast microscopes
highly viscous solution added to slides to slow down mo’s
protoslo
name of protozoans that feed on other organisms
chemoorganotrophic heterotrophs
advantages of using wet-mount preparations of MO’s
it allows seeing motility, easier to do/use, living specimens
why is vaseline used when making wet mount?
creates a seal around MO’s, prevents MO from getting crushed and allows them to be motile
three characteristics that protozoa and animal cells share
no cell walls, have mitochondria, non-photosynthetic
distinguish between cysts and trophozoites
- cysts are the inactive form of a protozoa
- trophozoites are actively growing form for protozoa
orientated movement towards or away from a stimulus response to their enviornment
chemotaxis
describe a protozoan pellicle
composed of plasma membrane and rigid protein layer beneath
phylogenetic classification schemes frequently use 18s rRNA sequence data. Explain/discuss
Structure and function of MOs are similar but change structure over time. The 18s rRNA sequence data is used to determine how close or not closely related organisms are
equation to covert F to C and C to F
C= 5/9(F-32)
F=9/5(C) + 32
- eukaryotic
- oxygen producing photosynthic
- lacks vascular system
algae
where is algae found?
free living in aquatic and on moist surfaces
advantages/disadvantages of hanging drop vs standard wet mounts
- hanging drop is more complex but allow for long observation and remove pressure on the MO from the coverslip
- Wet mount tends to dry out quick under microscope but is simpler to use
3 common uses of diatomaceous earth
- aquarium filters
- abrasives (polish, tooth paste)
- reflectiveness of road signs
distinguish between Brownian motion and vital motion
- brownian motion-wiggle and vibrating movement of atoms
- vital motion-random movement
define the endosymbiotic theory in reference to the origin of chloroplasts
the ability to perform endocytosis, the engulfment of bacterial prey that weren’t digested will give the bacterial cell energy
chloroplast arose from endosymbiotic cyanobacteria
what are negative stains? And how are they useful for observing sheaths and capsules surrounding MOs
negative stains use acidic dyes to identify MO’s under a microscope. They have a negative charge and most MO’s have a negative surface, the dye is repelled and stains the back ground not MO. The MO is therefore not harmed and the sheath/capsule is still in place.
which characteristics of euglena resemble a protozoan? an Alga?
they are like flagellated protozoa because they have no walls and complex growth factor requirements (require milk, peas…)
euglena have the same photosynthetic pigments as green algae and have chloroplasts
green algea
Chlorophyta
golden-brown algae and yellow green algae
Chrysophyta
diatoms are algae in __________
Stramenophiles/Chrysophyta
dinoflagellates are algae in ___________
Pyrrhophyta
blue-green algae
cyanobacteria
red algae
Rhodophyta
contain phycobilliproteins as accessory pigments and store carbohydrate is glycogen
cyanobacteria
sites of N2 fixation
heterocyst in cyanobacteria
contrast between mo’s and the environment can be improved by
negative staining
functions of sporangia formation in slime molds?
they produce/release spores that hatch onto other organisms and begin the life cycle
What stage of the Physarum resemble molds? explain.
the plasmodium stage because a sclerotium is left behind until it is in a favorable environment to grow.
what stage of the physarum resemble protozoa
The flagellated swarm cell because it develops a flagella coming out of one end of the cell.
what roles do the slime molds play in nature? explain.
they creep along over moist . rotting logs, leaves and other organic matter, which it degrades.
- eukaryotic
- spore bearing
- non photosynthetic
- absorbe nutrients
- cell walls made of chitin
- reproduce sexually and asexually
fungi
- eukaryotic
- spore bearing
- non photosynthetic
- absorbe nutrients
- cell walls made of chitin
- reproduce sexually and asexually
fungi
a sac-like structure whose contents are converted into spores
sporangium
a multinucleate hyphae formed by repeat nuclear divisions not accompanied by cell division
coenocytic
fungi that is able to switch back and forth between yeast form and filamentous form
dimorphism
the vegetative part of a fungus, consisting of a mass of branching, thread-like hyphae
mycelium
why are Petri dishes incubated upside down
to prevent condensation
and lessens the risk that airborne particles will wattle in and contaminate the culture
what are some similarities and differences between the sporangia produced by Rhizopus and those produced by Physarum?
rhizopus sporangia form on tips of hyphae and physarum sporangia form at tips of cytoplasmic streaming of plasmodium
why do you think the stwo strains in Rhizopus are called plus and minus instead of male and female?
because there are no male and female parts of the strains
what are the characteristics of potato dextrose agar that favor the growth of fungi, while inhibiting the growth of most bacteria?
The pda is composed of dehydrated potato infusion and high amount of carbohydrates that encourages fungal growth, The use of sterile acid to lower the ph of this medium to 3.5 +- 0.1 inhibits bacteria growth
hyphae that are divided by cross walls (septa)
septate
a sexually produced fungal spore formed within an ascus
ascospore
cortical roots of plant cells that have been invaded by a fungi and produce a brached tree-like fungus inside the plant cell.
arbuscule
the division Deuteromycota is no longer used in fungal classification. Explain
deuteromycota; imperfect fungi, are MO that are left behind because they do not reproduce or divide.
name 2 human diseases caused by fungi belonging to the Ascomycota
Aspergillosis fumatas causes bronchopulmonary aspergillosis where fungus balls form in the lungs
-
Ergot, a disease brought on by ingesting rye infected with Claviceps purpurea
flat worms
Platyhelminthes
bilateral symmetry and a head and tail
Helminths
two types of Platyhelminthes
flukes-trematodes
tapeworms-cestodes
roundworms
Nematodes
zygomycota group of fungi
Rhizopus sp and Mucor
ascomycota group of fungi
Aspergillus sp and Penicillium sp
glomeromycota group of fungi
Glomus sp