Cell Bio Ch 8 Flashcards
FACS is?
Florescence activated cell sorter
Uses an antibody coupled to fluorescent dye, the antibody binds to only 1 cell type.
Single fluorescent cell gets a negative charge, and the non fluorescent get a positive charge. Accurate to 1 in a thousand cells.
Cells isolated from intact tissue
Extracellular membrane is disrupted by proteolytic enzymes.
EDTA chelates calcium on which the cell-cell adhesions depend.
Microdissection technique
Selected cells are dissected from thin tissue slices that are prepared for microscopic examination
Cut with laser
Disadvantages of using intact tissue for experiments
Not a convenient source of material.
Difficult to purify particular molecules from an intact tissue (too complex).
No way possible to do genetic manipulations on the livestock.
Cultured cells ____________
Continue to differentiate similar to their origin cells
Advantages of using cells from cultures for experiments
It provides a more homogeneous population of cells to extract material.
Convenient to work with in the lab.
Under proper conditions, most plants and animal cells can live, multiply and even differentiate in a tissue-culture dish.
In the lab they can be monitored continuously and effect of different media or hormones can be studied.
In addition, interactions between two cell types can also be studied.
Experiments done on cultured cells are called “in vitro” (“in glass”) in contrast to those done using intact organism “in vivo” (“ in the living organism”).
Primary culture
Culture prepared directly from tissue of the organism.
Secondary culture
Primary culture has been repeatedly cultured
____________ cells are widely used as a source of homogenous cells.
Eukaryotic
Problem with cell cultures
Cells die after finite number of cell divisions
replicative cell senescence
Cell death after a finite number of cell divisions.
2 main reason for cell death
Telomere shortening - cells have turned off production of Telomerase enzyme. As a result telomere shortening occurs with each cell division.
Activation of cell –cycle checkpoint mechanism that arrests cell cycle and is called “culture shock”.
How to overcome cell death
Provide telomerase to the cells.
Add oncogene to inactivate the checkpoint.
Most human cells used in labs are cancer cells
Transformed cell lines
Human cells used in lab, derived from cancer cells
Rodent cell lines
Do not turn off telomerase production. Can grow indefinitely if culture shock is avoided.
