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Cells are needed for the growth, to replace worn out and repair damaged tissues.
Cells MUST HAVE THE SAME GENETIC INFORMATION in order to keep the
characteristics same, nucleus contains instructions for making a new cell
A gene is a small packet of information which controls a characteristic or part of a
characteristic. The genes are grouped together on chromosomes. A chromosome
contains thousands of genes. A nucleus contains 46 chromosomes except for
The cell division that takes place in normal
body cells produces identical daughter
cells called MITOSIS. As a result of mitosis
all body cells have same GNENETIC
INFORMATION. This happens in SOMATIC
CELLS (root hair, fat cell etc)
Before a cell divides it produces new copies of chromosomes, this means when cell
division takes place two identical daughter cells are formed. In some areas of the
body, cell division like this happens rapidly. E.g. skin cells are constantly being lost
and new cells are formed by cell division to replace them.
DIFFERENTIATED CELLS- specialised for a particular function
Unspecialised embryo cells are called STEM CELLS and these cells can become any
type of cells.
In animals, the cells become specialised early in the life. By the time a human baby are
born most of its cells have DIFFERENTIAITED. This means muscle cell divides by mitosis and
can only form muscle cells and liver cells can only produce liver cells. These specialised
cells can divide by mitosis, but this can only be used to repair damaged
tissue and replace worn out cells
Plant cell don't differentiate until they're in the final position. The differentiation is
not permanent in plants.
This is how we can produce number of plant cells from a tissue; each of the
undifferentiated cells will produce more cells by mitosis. Animal clones cannot be
made easily because animal cells differentiate PERMANENTALY early in the embryo
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Human stem cells are found in HUMAN EMBRYOS + ADULT TISSUE including bone
In embryo, stem cells are divided into many
other specialised cells.
In adults stem cells can stay there for many years
until tissues are injured or affected by disease.…read more
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Embryonic stem cells and adult stem cells can be made to differentiate into different types of