Lab 1 Flashcards
Ocular
Function: To magnify the specimen. Magnification is usually 10X and is engraved on the top of the objectives.
Revolving nosepiece
Function: To house the objectives and allow the various objectives to be moved into or away from the viewing position
Iris diaphragm ring (or lever)
Function: Controls the amount of light from the light source
Stage travel knobs
Function: To move the slide over the stage surface
Magnification
The total magnification of the microscope equals the magnification of the ocular lens times the magnification of the objective lens being used.
Cells
are the fundamental unit of life. All living things are composed of cells. While there are several characteristics that are common to all cells, such as the presence of a cell membrane, cytoplasm, DNA and ribosomes, not all cells are the same.
two types of cells
prokaryotic and eukaryotic cells
Prokaryotic cells
lack a nucleus and Organisms belonging to the domains Bacteria and Archaea are composed of
Eukaryotic
cells have a nucleus and organisms belonging to the domain Eukarya (protists, fungi, plants and animals) are composed of eukaryotic cells.
Size of cells
Prokaryotic cells are generally much smaller than eukaryotic cells (~about ten times smaller) and lack a nucleus and other membrane-bound organelles, whereas eukaryotic cells are compartmentalized by membrane-bound organelles with specialized functions, and the DNA is contained inside the nucleus.
cytoplasm
is the region of the cell outside the nucleus. It contains fluid, ribosomes, the cytoskeleton, and, in eukaryotes, other membrane-bound organelles such as the mitochondria and the chloroplasts (and many others).
plasma membrane
is a thin sheet of material that forms the outer surface of every cell. The plasma membrane surrounds all the parts of the cell and serves as the boundary between the cell and its environment.
Plant cells
have cell walls
Animal cells
do not have cell walls
Observing plant cells under the microscope
- Obtain a clean microscope slide and a cover slip.
- Take a piece of the Elodea leaf. You may have to cut it in half it is too big.
- Place the Elodea leaf in the center of the slide.
- Place a drop of water on the leaf specimen.
- Touch one side of the cover slip on the drop of water then lower the entire coverslip on top of the specimen.
- Wipe off any excess water.
- Examine the wet mount preparation using the scanner, low and high power objectives.
- Make sketches of your observations. Indicate the magnification of your specimen.