List two external and two internal factors that regulate the cell cycle
Answers
Explanation:
External factors come from outside the cell, could be
from other cells or from another part of the body.
Physical Signals
cell to cell contact
when mammal cells are grown in a culture dish
they form a single layer of cells on the bottom and
then stop dividing.
Chemical Signals
cells release chemicals that tell other cells to grow.
Growth Factors broad group of proteins that
stimulate cell division.
they bind to receptors that activate specific
genes to trigger cell growth
cells grow and divide in response to a combination of
growth factors
Growth factors affect many different types of cells.
Platelets are sticky fragments of bone marrow cells.
Form clots to stop bleeding
Store a type of growth factor that helps your body
repair wounds.
Other growth factors are target specific
Erythropoientin stimulates the production of red
blood cells
Red blood cells carry oxygen
If you moved from the coast to the mountains your
blood oxygen levels would be lower because
the air pressure is lower at higher altitudes. So
your body would produce more erythropoientin to
increase the number of red blood cells and increase the
amount of oxygen.
Growth hormones results in bone growth and affect
your protein and fat metabolism.
Internal Factors come from inside the cell and include several
types of molecules found in the cytoplasm.
1. Kinases enzymes that transfers a phosphate group
from one molecule to a specific target molecule.
this increases the energy or changes the shape
of the target molecule
kinases that control the cell cycle are activated by
cyclins.
2. Cyclins group of proteins that are rapidly made and
destroyed at certain points in the cell cycle.
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Answer:
Explanation:
1. Release of growth promoting hormones. For example in humans, lack of human growth hormone leads to dwarfism while too much of it leads to gigantism.