Download Cyclin and Cancer Lesson

Recall that DNA is instructions for making protein.
Just as a cookbook is divided into recipes…
…DNA is divided into segments called “genes.”
Cyclin
Cyclin
R of the cell
P
C cycle.
C
Protein
that controls the rate
C
D
In other words, cyclin
controls how often a cell divides.
Cyclin A
Cyclin B
S cells divide every 24 hours.
H
Skin
Cyclin A
L
Y
Liver
cells: divide every year.
Cyclin B
N
D
Nerve
cells NEVER divide…
Cyclin C
B
S
P
…which is why brain
and spinal
cord injuries are permanent.
Again, cells know how often to divide because cyclin protiens
“tell” them what to do.
Skin Cells
Liver Cells
Nerve Cells
Every 24 hours
Every year
Never
So what would happen to a cell without
cyclin?
C cycle
C
Without cyclin, the cell would move through the cell
too
F and would divide
D
fast
uncontrollably.
C
T
A mass of cells,
called a tumor,
forms.
This condition is known as cancer.
Cancer
Unregulated cell division
caused by cyclin
proteins not being
D
C
I
made, or being made incorrectly.
How the @(%#*% does cyclin change?
P
C
R
Like all proteins,
cyclin
is made by the cell’s ribosomes
D instructions.
following DNA
ribosome
DNA
Cyclin
Amino acids
D changes,
C
C
I
If the DNA
the cyclin
could be made incorrectly,
C
leading to cancer.
ribosome
DNA
Cyclin
Amino acids
And how the @(%#*% does DNA change???
M
E
DNA is a molecule.
Something with enough energy
could
B
break its bonds.
Radiation
R
1. Radiation
(solar, nuclear, etc.)
C
2. Chemicals
Cancer caused by radiation
Radiation
S cancer (melanoma)
M
S
Skin
is caused by solar
radiation.
Radiation
Melanoma happens when solar radiation breaks bonds in the
cyclin gene. Other proteins are not affected.
X
Cyclin
Melanoma often affects moles, because the darker-colored
cells absorb more solar radiation.
Radiation
On its own, melanoma is not very dangerous, since the tumor
forms on the outside of the body. Such tumors can be easily
removed.
Radiation
However, if left untreated, a skin tumor can metastasize.
Radiation
Metastasis
NEW PAGE
The spread
of cancer throughout the body;
happens when a
S
B
piece of a tumor
breaks off and enters the bloodstream.
T
B
Nuclear radiation, such as that released by a nuclear
explosion, has more energy that UV radiation. So it affects all
cells of the body – not just the ones on the outside.
Radiation
Also, the entire DNA molecule is affected by nuclear radiation
– not just one gene. So, all proteins are affected.
X
X
X
X
Cyclin
Exposure to nuclear radiation usually causes death before
cancer develops.
Radiation
https://nuclearsecrecy.com/nukemap/
Radiation sickness in Hiroshima, 1945:
Radiation
Nuclear radiation affects you inside and out, so unborn babies
are also affected:
Radiation
Cancer caused by chemicals
Radiation
L
C
Lung
cancer is caused by exposure to chemicals
(such as
T
tobacco
smoke).
Radiation
Other chemicals, such as solvents and cleaners, can also
cause lung cancer if they are inhaled.
Radiation
Lung cancer happens when the cyclin gene reacts with the
inhaled chemicals.
X
Cyclin
Tumor in dissected lung:
Radiation
Lung tumors in an x-ray (metastasized):
Radiation
Even if you are not exposed to radiation or
chemicals, you can still get cancer.
Radiation
E
D
Cancer can also be caused by random errors
during DNA
R
replication.
DNA replication:
Replication
Enzyme