Transcript Cycle Regulation and Cancer

 You
have learned that cells undergo division
to produce more cells for three reasons.
 You
have also learned the stages of the cell
cycle and mitosis.
 Does
this process go on uncontrolled?
 If not, what’s the control like?
 What happens when the control is lost.
7. What was the
relationship
between the
number of
cigarettes smoked
and the incidence
of lung cancer?
A. There was no relationship between cigarette smoking and lung
cancer.
B. As the number of cigarettes smoked decreased, the incidence of
lung cancer increased.
C. As the number of cigarettes smoked increased, the incidence of
lung cancer increased.
D. As the number of cigarettes smoked increased, the incidence of
lung cancer decreased.
Graph Analysis Review
1. What is the
independent variable?
2. What is the dependent
variable?

Identify some factors that control cell growth and division.

Describe the effect of environmental conditions on the cell
cycle.

Illustrate how feedback signals affect the cell cycle by
summarizing the events of each of the three checkpoints
of the cell cycle.

Restate how cancer relates to the cell cycle.

Distinguish between a benign tumor and a malignant
tumor.
 Cancer
 Tumor


Benign
Malignant
Cell division is highly controlled.
 What are the three factors that regulate cell growth &
division?
 Cell growth and division depends three main factors.
 1. PROTEINS: There are many proteins within the cell
that control the phases of the cell cycle.
 2. SIGNALS: Signals from surrounding cells or even
from other organs can also regulate cell growth and
division.
 3. SURROUNDINGS: Environmental conditions,
including the availability of nutrients, also affect the
cell cycle.


During the cell cycle, a cell undergoes an
inspection process to ensure that the cell is
ready for the next phase in the cell cycle.

Feedback signals at key checkpoints in the cell
cycle can delay or trigger the next phase of the
cell cycle.

There are three main checkpoints in the cell
cycle



G1 Checkpoint
G2 checkpoint
Mitosis checkpoint.
After chromosomes are
split into tow separate
nuclei (after telophase) the
cell makes sure they are
split up evenly.
If so the cell divides, if not
the cell gets destroyed.
After DNA is copied in the S
phase, it is critical that it has
been done correctly. The cell
checks the copies and
proceeds to mitosis only if
the DNA is copied exactly.
For cells that will
divide, this
checkpoint ensures
that the
surroundings are
right for DNA
duplication &
division.
Cells like nerve cells
never get out of this
stage. Cells like
muscle will spend a
long time in this
phase.
If faulty DNA is copied &
distributed into separate
nuclei then these cells can
proceed to produce
daughter cells.
This could lead to tumor
formation if it’s not
detected.
If faulty or damaged DNA is
copied, this could be allowed
to proceed into mitosis.
If DNA gets damaged
then the cells can’t
check it’s
surroundings
correctly
This could lead to
faulty DNA to be
copied.
 When
the cell cycle goes unchecked or
unregulated things get bad in the body.
 The most common result…

Each year, more than 1 million Americans are
diagnosed with cancer.

Cancer is a group of severe and sometimes fatal
diseases that are caused by uncontrolled cell
growth.

Uncontrolled cell growth and division can result
in masses of cells that invade and destroy
healthy tissues.
Loss of Control
 Normally, a cell responds properly to signals and
controls.

In these times, cells only divide when they are supposed
to.

When DNA, and the genes associated with them,
gets damaged the signals and proteins don’t
work properly.

The defective cell divides and produces more
defective cells. Eventually, these cells can form
a mass called a tumor.

[Tumor: a growth that arises from normal tissue but that
grows abnormally in rate and structure and lacks a
function]
Brain
Lungs
Lymph
nodes
 Testicles
 Breasts
 Skin
 Stomach
 Eyes
 See
the theme?
Any
cell or organ that has DNA &
goes through mitosis can get
cancer.
Development
 A benign tumor does not spread to other parts of
the body and can often be removed by surgery.


A malignant tumor invades and destroys nearby
healthy tissues and organs.


These tumors are generally not that harmful.
These are the tumors to be afraid of.
Malignant tumors, or cancers, can break loose
from their tissue of origin and grow throughout
the body. This process is called metastasis.
Once a cancer has metastasized, it becomes
difficult to treat.
 There
are many causes of cancer but for the
most part they come from…




Carcinogens
Intercalating compounds
Anything else that causes irreversible damage to
the genes in DNA responsible for regulating cell
growth & development.
http://www.cancer.org/Cancer/CancerCauses/Ot
herCarcinogens/GeneralInformationaboutCarcino
gens/known-and-probable-human-carcinogens
 Smoking

Lung cancer
Alcohol

Esophageal

carcinoma
 Ultraviolet
(UV) or other forms of radiation;
from the sun, atomic weapons & reactors,
radioactive matter (uranium), etc.


Basal carcinoma
Melanoma
 Cell


phones?
Brain tumors
We’ll see the
data in your
generation.

Some cancers can be treated by using drugs that kill the
fast-growing cancer cells.


Because drugs are chemicals, this method of treatment is called
chemotherapy, or “chemo” for short.
Some cancers can be treated by surgery to remove of the
affected organ.

Ultra-refined lasers

In radiation therapy, high-energy rays are focused on an
area in order to destroy cancerous cells.

There are homeopathic treatments available, a highly
supported nouveau methodology that uses treatments
that are much more natural, personalized, and
supportive than traditional “big-pharma” treatments.

See: http://www.burzynskiclinic.com/ for an example.
Prevention
 The best way to prevent cancer is to avoid things
that can cause cancer.





Wear sun block
Limit exposure to smoke
Limit exposure to alcohol intake
Limit micro-radio wave exposure
Avoid anything on the list of known carcinogens
 Quiz
Q1: What is cancer (define it)?
Q2: How do cancer cells affect healthy cells?
Q3: What is the reason that cancer cells do
not respond properly to cell signals and
controls?
Q4: What can form in the body as a result?
Q5: What is the difference between a benign
tumor and a malignant tumor?
Q1: What is cancer (define it)?

A1: Cancer is a group of severe and sometimes fatal diseases
caused by uncontrolled cell growth.
Q2: How do cancer cells affect healthy cells?

A2: Cancer cells result in masses of cells, called a tumor, that
invade and destroy healthy tissues.
Q3: What is the reason that cancer cells do not respond properly to cell signals and controls?

A3: Damage to a cell’s DNA can cause the cell to respond
improperly or stop responding to normal signals and controls.
If this happens, the cell cycle can’t be controlled. The
defective cell divides, producing more defective cells. A mass
of these cells forms a tumor.
Q4: What can form in the body as a result?

A4: Tumors
Q5: What is the difference between a benign tumor and a malignant tumor?

A5: A benign tumor does not spread to other parts of the body.
Benign tumors are usually easy to remove. Cells in malignant
tumors invade and destroy nearby healthy tissues and organs;
they can also break loose and spread to other parts of the
body.

Cell growth and division depend on protein
signals and other environmental signals.

Feedback signals at key checkpoints in the cell
cycle can delay or trigger the next phase of the
cell cycle.

Uncontrolled cell growth and division results in
tumors, which can invade surrounding tissues
and cause cancer.