2. Cell Culture
– Cell culture refers to the removal of cells from an animal
or plant and their subsequent growth in a favourable
artificial environment.
– There are three major types of cell culture, which
include:
i. Primary cell culture
ii. Secondary cell culture, and
iii. Cell line
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3. Primary cell Culture
– Primary cell culture refers to the stage of the
culture after the cells are isolated from the tissue
and proliferated under the appropriate conditions
until they occupy all of the available substrate
(i.e., reach confluence).
– At this stage, the cells have to
be subcultured (i.e., passaged) by transferring
them to a new vessel with fresh growth medium
to provide more room for continued growth.
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4. Primary cell culture is further
classified based on the type of cell:
ADHERENT CELL SUSPENSION CELL
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5. Adherent cells
Those cell which attach to the surface
of the culture flask.
Forms a monolayer.
They must be detached from the
surface before they get sub cultured.
Growth limited to surface area.
Also known as anchorage cells.
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6. Suspension cell
Those cell does not get attached to the
surface of culture flask.
They are free floating.
Cells in blood stream.
Growth is limited to concentration of cells.
Also known as anchorage independent
cells.
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7. Cell Lines
– After the first subculture, the primary culture becomes
known as a cell line or secondary cell culture
or subclone.
– Cell lines derived from primary cultures have a limited
life span (i.e., they are finite; and as they are passaged,
cells with the highest growth capacity predominate,
resulting in a degree of genotypic and phenotypic
uniformity in the population
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8. On the basis of the life span of culture, the cell
lines are categorized into two types:
Finite cell lines
Continuous cell
lines
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9. Finite cell lines
–The cell lines which go through a limited
number of cell division having a limited life
span are known as finite cell lines.
–The cells passage several times and then
lose their ability to proliferate, which is a
genetically determined event known
as senescence.
–Cell lines derived from primary cell
cultures of normal cells are finite cell lines.
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10. – When a finite cell line undergoes transformation and
acquires the ability to divide indefinitely, it becomes
a continuous cell line.
– Such transformation/mutation can occur spontaneously
or can be chemically or virally induced or from the
establishment of cell cultures from malignant tissue.
– Cell cultures prepared in this way can be sub-cultured
and grown indefinitely as permanent cell lines and are
immortal.
Continuous cell lines 10