Artificial Intelligence In Microbiology by Dr. Prince C P
Cell cycle n its regulation
1. Cell Cycle and its Regulation
Dr Sanjita Das
https://www.youtube.com/watch?v=eqJqhA8HSJ0
https://www.youtube.com/watch?v=k2DBsovDXxE
2. How does a cell know when to
divide and when not to divide?
3. Regulation of the Cell Cycle
• Internal and external factors regulate cell
division.
– External factors – factors or signals that come
from the outside of the cell that help to control
the division process
– Internal factors – factors or signals from the
inside of the cell that control the division
process
5. Cell to Cell Contact
• Once a cell touches other cells it stops
dividing.
• The exact reason is considered a
phenomenon and is unknown.
• One hypothesis suggests that receptors
on neighboring cells bind to each other
and trigger the cytoskeleton to block
signals that will trigger growth.
6. Growth Factors
• Growth factors are a broad group of
proteins that act as chemical signals
released from other cells to tell other cells
to divide.
• Growth factors bind to receptors that
activate specific genes to trigger cell
growth.
• Cells will usually respond to a combination
of several growth factors not just one.
7. Examples
• Erythropoietin-stimulates the production of red blood cells
and becomes present when oxygen levels are depleted.
– Platelets-form clots to
stop bleeding and
carry growth factors
that helps your body
repair wounds by
signaling certain cells
to divide.
8. Hormones
• Hormones stimulate the growth of certain
cell types.
– Ex. Growth hormone results in bone growth
and also affects metabolism.
10. Kinases and Cyclins
• Kinases are enzymes that when activated
transfer a phosphate group from one
molecule to a target molecule. This gives
energy or changes the shape of the target
molecule.
• Some kinases help to control the cell cycle.
• Cyclins are proteins that are rapidly made
and broken down that activate kinases.
11. Apoptosis
• Just as some cells need to divide, some
cells need to die.
• Apoptosis is programmed cell death.
• Internal or external factors stimulate genes
that activate self destructive enzymes.
• The cell will then be recognized and
ingested by immune system cells.
13. Cancer
• Cancer is a common or generic name
given to diseases that are characterized
by uncontrolled cell division.
• Cancer cell will continue to divide without
the presence of growth factors and will
also continue to divide when in contact
with other cells.
• Cancer cells divide much more than
healthy cells.
14. Tumors
• When clumps of cancer cells form they are
called tumors.
• Two types:
– Benign
– Malignant
15. Benign Tumors
• Benign tumors usually remain localized
and do not spread.
• Usually harmless and may be cured
simply by removal.
18. Malignant Tumor
• In a malignant tumor certain cells may
break away from the tumor and spread.
• When cancerous cells spread, we say that
they metastasize.
– Done by entering the blood and lymp vessels
of the circulatory system where they invade
other areas and form new tumors.
• Tumors are difficult to eradicate once they
metastasize.
23. Cancer Cells
Tumors
– Cancer cells don’t perform the specialized
functions needed by the body.
– The body has large volumes of rapidly
dividing cells that require lots of blood and
energy but pose no usefulness to the body.
– Tumors can exert pressure on vital organs
when they become too large.
25. • Cancer cells will usually come from normal
cells that have suffered damage to their
genes (mutations) that are associated with
making proteins that regulate the cell
cycle.
• Oncogenes are one type that will
accelerate cell growth.
• Other genes act as cell cycle brakes.
33. Viruses
Some oncogenes may be carried by a virus
and cause cancer (e.g. cervical cancer
often results from the Human papilloma
virus - HPV).
• The HIV virus leaves the body more
susceptible to cancer.