Nov 16th, 2009 by Mr. Saxby
Warm-up: If cells only divided, the result would be a big ball of identical cells! Instead, cells differentiate. Open the text to page 138 and write the definition of differentiation.
Differentiation is the process by which cells change in structure and become capable of carrying out specialized functions. It’s how they become a special type of cell and get a special job.
Class work: Students discussed the warm-up and stem cells then watched a short video on Cell Division available in class. We then finished the notes on the phases of mitosis in the Cell Cycle Notes.
We discussed how animals, like us, have special cells called stem cells that can differentiate at any time. After early development before birth the other 200 types of cells in our bodies cannot. We learned scientists at Stanford are using a gene inserted into mice to make a glowing jellyfish protein in all the mice cells that allows them to track these cells when injected into other mice in stem cell studies.
The scientist who isolated this protein from jellyfish shared the information with scientists who won the Nobel Prize this year. He is driving a cab now.
Plants, on the other hand, have cells that can differentiate anytime. Root cells can turn into leaf cells and vice versa. You can break off a piece of a plant and it will usually grow root cells if in water. You can cut off a weed below the soil with a shovel, like the mustard brought by the Jesuit padres who built the missions, and it will grow new leaves from the root cells.
Homework: Please read in the text 138-139 and answer text 141 #1a on spiral 62. Bring 8 blank flashcards.
