BIOL Lab 1: Microscope Flashcards
Simple Stains
Many colored molecules (dyes) will irreversibly bind to biological molecules, just as they will to fabrics or your hair. Such stains usually kill living cells, since they block the molecules to which they bind from cellular activity.
Methylene Blue
A common positively charged dye that will bind to negatively charged molecules such as nucleic acids, many proteins, and some polysaccharides. Hence, Methylene blue is a non-specific dye; it usually stains all organelles and many smaller molecules as well.
Sudan Black
A fat soluble dye that selectively binds to fatty materials, thus showing if and where such materials are deposited within cells.
Vital Stains
Chemicals that can stain living cells without killing them. Organelles such as vacuoles (which are found in plant cells) can be made visible with a vital stain because of their functional tendency to take in water-soluble materials for storage.
Neutral red becomes concentrated in the vacuoles of plant cells.
Janus Green B
Another vital stain that takes advantage of the functional activity of another organelle, the mitochondrion. Mitochondria are the site of cellular respiration. When an aqueous solution of the blue (oxidized) Janus green B stain diffuses into the cell, it is first reduced in the cytoplasm to a colorless form, but then re-oxidized in the mitochondria to the blue form.
Sectioning
A technique used to obtain smaller, manageable sized specimens from larger material. Often times a 3D specimen may be too dense to view under a compound microscope. In order to see finer detail or, for instance, view the internal anatomy of a small organism, the specimen may be cut into layers along different plans. Depending on if the specimen is sectioned and how the specimen is sectioned, the slides you view in lab will denote this with the abbreviations WM, CS, IS…. Knowing if and how a specimen was sectioned will provide you with a better idea of how those cells of tissue types are actually arranged in 3D space.
w.m. (Whole Mount)
Refers to mounting a complete specimen without any sectioning done.
c.s. (Cross Section)
Refers to mounting a specimen cut horizontal to the top and bottom orientation of the specimen.
l.s. (Longitudinal Section)
Refers to mounting a layer of the specimen from a cut vertical to the top and bottom orientation of the specimen.
Hydra Sections
Hydra are small aquatic organisms related to jellyfish (Phylum Cnidaria). They adhere to surfaces and catchy prey with their long, stinging tentacles.
