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BSC 203 Exam 1 questions with verified solutions
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BSC 203 Exam 1 questions with verified solutions
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BSC 203 Exam 1light microscope - correct answer ✔✔uses visible light to illuminate specimen. Also allows us to magnify
cells up to 1000 times and to resolve details that are very tiny(0.2 um)
1)A bright light must be focused onto the specimen by lenses in the condenser
2)The specimen must be carefully prepared to allow light to pass through it
3)Set of lenses must be arranged to focus an image of the specimen in the eye - correct answer
✔✔What are the three things required for viewing cells in a light microscope?
transmission electron microscope - correct answer ✔✔-uses a beam of electrons instead of a beam of
light and magnetic coils to focus the beam instead of glass lenses.
- specimen is stained with electron-dense heavy metals that absorb or scatter electrons,
-Can resolve details as small as about 1nm in biological specimens
confocal microscopy - correct answer ✔✔-special type of fluorescence microscope that builds up an
image by scanning the specimen with a laser beam
-the beam is focused onto a single point at a specific depth in the specimen, and a pinhole in the
detector allows only fluorescence emitted from this same point to be included in the image
-provides an optical section showing the individual cells clearly
scanning electron microscopy - correct answer ✔✔-Specimen is coated with a very thin film of a heavy
metal
-is scanned by a beam of electrons brought to a focus on the specimen by magnetic coils that act as
lenses
-microscope creates three-dimensional objects with great depth of focus and can resolve details down
between 3 nm and 20 nm
,fluorescence microscope - correct answer ✔✔-fluorescence dyes are used for staining cells and are
detected
-illuminating light is passed through two filters
-1st filters the light before it reaches the specimen, passing only those wavelengths that excite the dye
2nd blocks out this light and passes only those wavelengths emitted when the dye fluoresces. Dyed
objects show up in bright color on a dark background
1. The smallest clearly defined unit of life is the cell (Schwann)
2. All living organisms are composed of cells. (Schwann)
3. Cells arise only from other cells (Virchow)
4. Each cell can maintain its living properties independently from the rest, but the properties of life
displayed by any organism depend on the properties of the cells its made of. (Virchow) - correct answer
✔✔What are the four points of cell theory?
-bacteria(one of the two divisions of prokaryotes)
-lack a nucleus
-spherical, rod like, or corkscrew
-small
-most diverse
-single celled
-can live in any habitat
-use binary fission
-circular DNA
-don't have membrane bound organelles - correct answer ✔✔What are the characteristics of a
prokaryotic cell?
-bigger and more elaborate
-ex: amoeba and yeasts (single celled)
-nucleus
-mitochondria
, -chloroplasts
-cytoskeleton
-linear DNA
-internal membranes
-plants, animals,fungi
-reproduce through mitosis - correct answer ✔✔What are the characteristics of a eukaryotic cell?
ribosomes, DNA, cytoplasm, cell membrane, reproduce asexually - correct answer ✔✔What do
prokaryotes and eukaryotes have in common?
Totipotent - correct answer ✔✔A cell that can divide and produce all the differentiated cells in an
organism. Found in mammals.
Pluripotent - correct answer ✔✔A cell that has the potential to differentiate into any of the three germ
layers: endoderm, mesoderm, or ectoderm
. Abundant in embryos
multipotent - correct answer ✔✔Cells that can give rise to a limited number of other cell types. Found in
the tissues of adult mammals
1)embryonic
2)adult stem cell
3)induced pluripotent stem cells - correct answer ✔✔What are the sources of stem cells?
Advantage: iPS cells will not be rejected by the immune system of the individual from whom the cells
were derived.
Disadvantage: Introduced genes can cause uncontrolled cell growth (tumors and teratomas).
- Epigenetic effect issues. - correct answer ✔✔What is the advantage and disadvantage of pluripotent
stem cells special?
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