Cell Cycle Dr. Nichols Coronado HS

Question of the day! What are your feelings about human cloning? Do you agree or disagree with this technology? Why?

Stages of the cell cycle The cell cycle is broken into 5 stages. 1.) G1 2.) S phase Interphase 3.) G2 4.) Mitosis 5.) Cytokinesis Let’s explore each in more depth.

G1 (Gap 1) Cells increase in size in G1. The G1 checkpoint control mechanism ensures that everything is ready for DNA synthesis (which is the next step).

S phase (synthesis) DNA replication occurs during this phase. What is the purpose of this step?

G2 (gap 2) During the G2 phase the cell will continue to grow and make more organelles!!! The G2 checkpoint control mechanism ensures that everything is ready to enter the Mitosis phase and divide.

In summary Today! 

Steps in mitosis 0. Interphase (G1, S, G2, the steps before) 1. Prophase 2. Metaphase New Today 3. Anaphase 4. Telophase [5* Cytokinesis]

1.) Prophase During prophase chromosomes in the nucleus condense, and the nuclear envelope breaks down.

prophase

2.) Metaphase During metaphase, the chromosomes are pulled by microtubules called spindle fibers into place. The chromosomes line up on the cell's equator, or center line, and are prepared for division.

metaphase

3.) Anaphase During anaphase, the chromosomes move from the cell's equator (metaphase plate) to their respective poles of the cell. The cell begins to stretch out as the opposite ends are pushed apart.

anaphase

4.) telophase One complete set of chromosomes is now at each pole of the cell. The spindle fibers begin to disappear, and a nuclear membrane forms around each set of chromosomes. Also a nucleolus appears within each new nucleus.

Telophase

5.) Cytokinesis This is where the cell physically splits, the cytoplasm splits and the two cells pull away from one another.

In summary Today! 

Introducing Henrietta Lacks (Died in 1945)

Who was Henrietta Lacks? What’s her story? Who was Henrietta Lacks? She was a black tobacco farmer from southern Virginia was diagnosed cervical cancer when she was 30. A doctor at Johns Hopkins took a piece of her tumor without telling her and sent it down the hall to scientists there who had been trying to grow tissues in culture for decades without success. No one knows why, but her cells never died….and are still being used today!

Cool, but why is this important? What do you all think? Henrietta’s cells (HeLa Cells) were the first immortal human cells ever grown in culture. They were essential to developing the polio vaccine. They went up in the first space missions to see what would happen to cells in zero gravity. Many scientific landmarks since then have used her cells, including cloning, gene mapping and in vitro fertilization.

The plot thickens! When Deborah’s brothers found out that people were selling vials of their mother’s cells, and that the family didn’t get any of the resulting money, they got very angry. Henrietta’s family has lived in poverty most of their lives, and many of them can’t afford health insurance. One of her sons was homeless and living on the streets of Baltimore. So the family launched a campaign to get some of what they felt they were owed financially. It consumed their lives in that way.

Wrap up discussion Was the family justified in wanted financial compensation for their family member’s cells? Do the discovered benefits of HeLa cells outweigh the cons of not getting consent from Henrietta and/or her family? Should politics and legislation have a role in the advancement of science? What role does Mitosis play in the technologies discovered using Henrietta’s cells?

Ready, set, draw! Create a cartoon strip that illustrates all of the stages of the cell cycle, including all the separate stages of mitosis :D The most creative and well done may receive extra credit! Put some effort into it! Color is optional but highly encouraged,