Viruses & Cell Cultures

Question 0

disadvantages of cell cultures

Answer 0

• Does not always mimic in vivo conditions in terms of gene expression
• Chromosome abnormalities
• Cells are nondifferentiated, though some differentiated types can be grown
• Primary cell cultures are short-lived and tumor cells will divide indefinitely

Question 1

Advantages of working with cell cultures

Answer 1

• More homogeneous than cells in tissues
• Can control experimental conditions
• Can isolate single cells to grow into a colony of genetically homogeneous clone cells

Question 2

What is oncogenic transformation?

Answer 2

rare cells in a population of primary cells that undergo cer- tain spontaneous genetic changes, called oncogenic transfor- mation, are able to grow indefinitely. These cells are said to be oncogenically transformed or simply transformed. A cul- ture of cells with an indefinite life span is considered immor- tal and is called a cell line

Question 3

What is replica plating?

Answer 3

replica plating is a technique in which one or more secondary Petri plates containing different solid (agar-based) selective growth media (lacking nutrients or containing chemical growth inhibitors such as antibiotics) are inoculated with the same colonies of microorganisms from a primary plate (or master dish), reproducing the original spatial pattern of colonies.
The purpose of replica plating is to be able to compare the master plate and any secondary plates, typically to screen for a desired phenotype. For example, when a colony which was present on the primary plate(or master dish), fails to appear on a secondary plate, it shows that the colony was sensitive to a substance on that particular secondary plate.

Question 4

Requirements for the growth of animal cells in culture

Answer 4

• Requires rich media including essential amino acids, vitamins, salts, glucose, and serum
• Most grow only on special solid surfaces

Question 5

Primary cells and cell lines

Answer 5

• Primary cell cultures are established from animal tissues
• Certain types of cells are easier to culture than others
• Most cells removed from an animal grow and divide for a limited period of time (about 50 doublings), then eventually die
• Certain “transformed cells” may arise that are immortal and can be used to form a cell line
• Transformed cells may be derived from tumors or may arise spontaneously
• The rate of spontaneous transformation varies for different species

Question 6

Cell fusion

Answer 6

• Two different cells can be induced to fuse thereby creating a hybrid cell (heterokaryon)
• Interspecific hybrids may be used for somatic-cell genetics
• Certain hybrid cells (hybridomas) are used to produce monoclonal antibodies

Question 7

All about virus structure, function, and use

Answer 7

• Viruses are small parasites that cannot reproduce by themselves
• A virus infects a suitable cell and utilizes the host cell machinery to produce more viruses
• A virus consists of nucleic acid (RNA or DNA) surrounded by a shell of protein
• Viruses either infect prokaryotic or eukaryotic cells and the host range of most viruses is narrow
• Study of viruses has furthered understanding of basic aspects of cell biology as well as the development of cancer
• Have useful gene promoters for transgenic research