Cell Differentiation/Stem Cells

Cell Replication Normally, when a cell undergoes mitosis it produces more cells of that same type. For example, a bone cell that undergoes mitosis will produce more bone cells. However, some cells undergo a process called cell differentiation Cell Differentiation – When one cell type divides to produce a different cell type.

Cell Differentiation Not all cells can go through Cell Differentiation. A blood cell undergoing mitosis will never be able to turn into a nerve cell The only kind of cells that can do this process are stem cells There are two types of stem cells: Adult Stem cells The can only be found in adult bodies (bone marrow, bottom layers of skin, etc.) These stem cells can only become certain kinds of cells Ex. Skin stem cells can only become skin cells

There are also Embryonic Stem Cells Only Found in embryos (developing offspring) These stem cells can become any kind of cell.

What influences cell differentiation There are 3 things that control how cells differentiate The 3 Differentiation factors are: Proteins Enzymes Temperature

In what way do cells change? Cells Change in 3 ways when they undergo cell differentiation Cells: Increase in number Cells specialize in structure Cells specialize in function

Losing Control of the Cell cycle

Control of the Cell Cycle Certain genes in your DNA control the production of proteins that regulate cell growth and division. Proteins act like gatekeepers that will only allow a cell to continue if everything is perfect. If one of these genes are mutated, regulation of cell growth will be disrupted.

2. G2/M checkpoint - point where cell commits to mitosis Checkpoint - specific points where cell cycle can be put on hold. There are three mitosis checkpoints 1. G1/S checkpoint - main point where the cell decides whether or not to divide 2. G2/M checkpoint - point where cell commits to mitosis 3. spindle checkpoint – makes sure that all chromosomes attached to spindle for anaphase

But what if certain genes are mutated and the checkpoint proteins don’t work correctly? Cancer: uncontrolled growth of cell Some mutations cause cancer by over-producing growth-promoting molecules and speed up the cell cycle If allowed to continue, the cancer cells will begin to overtake the normal cells. Some mutations cause cancer by inactivating the checkpoint proteins that would normally stop some cells from dividing…so then those cells keep dividing.

Cancer: uncontrolled growth of cell

Normal Cell Division vs. Unregulated Cell Division(Cancer)

The Good News… Treatment of cancer Chemotherapy Radiation Surgery-removal of the tumor/ or cancerous cells Gene-therapy