There are three stages in the cell cycle: The cell cycle in embryos is very short
but the process slows down for adults.
Biology Chapter
1. Longest stage. Cells grow, increasing in
Differentiate: The process where cells
2
Cell cycle: the three-stage process
mass. At the end of stage 1 the cells
of cell division in a body cell.
replicate their DNA to make two copies of change and become specialised.
every chromosome. They also make more Egg and sperm (gametes) have 23
Stem cells: Undifferentiated cells with
sub-cellular structures. chromosomes each and combine
the potential to form a wide variety of
2. Mitosis = One set of chromosomes is to form 46 chromosomes.
different cell types.
pulled to each end of the dividing cell and
the nucleus divides. Adult stem cells: Stem cells that are
3. The cytoplasm and cell membrane divide found in adults that can differentiate
to form two new identical cells. and form a limited number of cells.
Plants are easy to clone because the cells can Usually found in the bone marrow.
become unspecialised, divide by mitosis, and Actively dividing plant tissues are called
the differentiate into the various types of plant meristems, found at the growing points
cell. It’s difficult to clone animals because once of plants. The cells produced by mitosis
the cells are differentiated, they cannot in the meristem then elongate and
become unspecialised again. differentiate. An egg and sperm fuse to form a
Cloning: The production of identical offspring When stem cells change into all the zygote.
by asexual reproduction. different types of body cell, such as
Researchers hope that human
Benefits of cloning plant are; rare plants can nerve cells or muscle cells, we say the
stem cells can be used to treat
be saved from extinction, large numbers of cells differentiate. Adult stem cells can
conditions like: Paralysis by
exotic plants can be produced for sale in change into other types of cells, such
differentiating into new nerve
horticulture, and plants can be produced with as blood cells.
cells and, diabetes by producing
special features like resistance to disease. The stem cells from plant meristems cells that are sensitive to blood
can be used to make clones of the sugar and produce insulin.
Embryonic stem cells come from aborted
mature parent plant very quickly and
embryos or spare embryos from fertility Therapeutic cloning: A process
economically.
treatment. There are risks, social and ethical where an embryo is produced
issues with this. People believe it is a violation that is genetically identical to
of the embryos right, some people believe this the patient so the cells can then
is playing god, some people think the money be used in medical treatment.
used on this could be going to other medical
conditions, there is a concern that stem cells
can cause cancer as they divide rapidly and the
project itself is proving to be slow and
expensive.
but the process slows down for adults.
Biology Chapter
1. Longest stage. Cells grow, increasing in
Differentiate: The process where cells
2
Cell cycle: the three-stage process
mass. At the end of stage 1 the cells
of cell division in a body cell.
replicate their DNA to make two copies of change and become specialised.
every chromosome. They also make more Egg and sperm (gametes) have 23
Stem cells: Undifferentiated cells with
sub-cellular structures. chromosomes each and combine
the potential to form a wide variety of
2. Mitosis = One set of chromosomes is to form 46 chromosomes.
different cell types.
pulled to each end of the dividing cell and
the nucleus divides. Adult stem cells: Stem cells that are
3. The cytoplasm and cell membrane divide found in adults that can differentiate
to form two new identical cells. and form a limited number of cells.
Plants are easy to clone because the cells can Usually found in the bone marrow.
become unspecialised, divide by mitosis, and Actively dividing plant tissues are called
the differentiate into the various types of plant meristems, found at the growing points
cell. It’s difficult to clone animals because once of plants. The cells produced by mitosis
the cells are differentiated, they cannot in the meristem then elongate and
become unspecialised again. differentiate. An egg and sperm fuse to form a
Cloning: The production of identical offspring When stem cells change into all the zygote.
by asexual reproduction. different types of body cell, such as
Researchers hope that human
Benefits of cloning plant are; rare plants can nerve cells or muscle cells, we say the
stem cells can be used to treat
be saved from extinction, large numbers of cells differentiate. Adult stem cells can
conditions like: Paralysis by
exotic plants can be produced for sale in change into other types of cells, such
differentiating into new nerve
horticulture, and plants can be produced with as blood cells.
cells and, diabetes by producing
special features like resistance to disease. The stem cells from plant meristems cells that are sensitive to blood
can be used to make clones of the sugar and produce insulin.
Embryonic stem cells come from aborted
mature parent plant very quickly and
embryos or spare embryos from fertility Therapeutic cloning: A process
economically.
treatment. There are risks, social and ethical where an embryo is produced
issues with this. People believe it is a violation that is genetically identical to
of the embryos right, some people believe this the patient so the cells can then
is playing god, some people think the money be used in medical treatment.
used on this could be going to other medical
conditions, there is a concern that stem cells
can cause cancer as they divide rapidly and the
project itself is proving to be slow and
expensive.
