B.5(C) Lesson Cancer

Why do cells divide?

Cells divide to grow, replace dead or damaged cells, or in some cases to reproduce asexually.

Cell Cycle

• G1 - Cell grows

• S - DNA Replication

• G2 - Get ready to divide

• M (PMAT) - Division of Nucleus

• C- Division of cytoplasm

​If there are any errors that cannot be corrected at each checkpoint, the cell undergoes apoptosis - programmed cell death, appempt to avoid mutations/cancer

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Important!​

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To prevent the compromised cell from continuing to divide, internal control mechanisms operate at 4 cell cycle checkpoints:

1. G1 Phase

2. S Phase

3. G2 Phase

4. M Phase

​Occurs at the end of each phase

​Checkpoints

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Cell Death- Apoptosis

If a cell is "damaged" or broken, it can self destruct (apoptosis)

When cells do not self-destruct, that can also cause cancer cells.

Tumor Suppressor Gene

• Tells the cell to stop dividing.

• It is like brakes on a car

• When mutated, the cell cannot stop dividing

Multiple Choice

In a normal cell, what does a tumor suppressor tell the cell to do?

• Start dividing

• Stop dividing

• Divide twice

Proto-Oncogene

• Tells the cell to divide

• It is like the gas in a car

• When mutated it turns into an oncogene. The signal to divide is turned on all the time!

Multiple Choice

In a normal cell, what does the proto-oncogene tell the cell to do?

• Start dividing

• Stop dividing

• Divide twice

Multiple Choice

When a person gets a mutation in both the tumor suppressor gene and proto-oncogene, what disease do they have?

• Cancer

• Virus

• Infection

• Fungus

Cancer

Cancer occurs when the cell no longer responds to the normal signals to divide. There is uncontrolled cell growth. And cells are continuing to undergo mitosis.

Unregulated and uncontrolled cell growth

Cancer tumors are either:

• benign (not dangerous)

• malignant​ (dangerous)

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Cancer occurs when tumor suppressor genes do not work properly to prevent uncontrolled cell growth.

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​Cancer is...

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Tumors

A group of cancer cells is called a tumor

Carcinogens are cancer-causing agents that can cause mutations to your DNA.

Open Ended

Healthy non-cancerous cells spend 90% of their time in interphase and only 10% in mitosis.

Is this the same for cancer cells?

Multiple Choice

True or False: Cancer is basically an inability of the body to control the speed at which cells divide.

• True

• False

Multiple Select

Cancer is when cells divide _________________.

• uncontrollably

• unregulated

• continuously

• over and over again

Dropdown

Treatments like radiation, will destroy cells that are dividing ​

Select answer

Multiple Choice

What kind of cells are more likely to be killed during cancer treatments?

• Hair

• Nerve

• Bone

Multiple Choice

In a normal cell, what does a tumor suppressor tell the cell to do?

• Start dividing

• Stop dividing

• Divide twice

Multiple Choice

These are important points in the cell cycle that look for errors and stop the process if errors are detected to prevent changed cells

• Checkpoints

• Cell Cycle

• Apoptosis

• Interphase

Multiple Choice

What happens if a checkpoint detects any of the following within a cell: damage to DNA, errors in DNA replication, or incorrect attachment of spindle fibers?

• The process is stopped until these things are repaired or a cell is killed

• The process will stop but the cell will never be killed

• The process continues

• Checkpoints will not check for these things

Multiple Choice

Cancer cells divide at what speed compared to normal cells?

• Same

• Slower

• Faster

• It is not dividing

Multiple Choice

Cancer is described as _________________ cell growth.

• unregulated and uncontrolled

• regulated and controlled

• slow and steady

• checks and balances