Friday, April 27, 2007

Cell Structure

From the huge world of taxonomy we went to the tiny world of cells. Today we read a page from Rader's Biology 4 Kids on cells. From there we went to Cells Alive! to watch the neatest animation that zooms in on the head of a pin, down to hair, to dust mites, to pollen, to blood cells and finally to the rhinovirus so you can get a bit of a sense just how small these things are.

On to BrainPop where we watched videos on cells, DNA and RNA and then took their quizes. I didn't intend to cover anything on DNA or RNA today but Catherine was curious. It came in handy anyway when we came up with our project.

I tacked a big piece of kraft paper to one of the few free spaces on my living room wall and drew a big circle. I labeled the circle, "Cell Membrane" and the whole sheet was labeled "Animal Cell". Then there was some discussion. Because it was an animal cell it wouldn't have a cell wall and because it was a Eukayotic cell it would have to have a nucleus. Off to the kitchen where we visited Rader's Biology 4 Kids again to find a page on the nucleus. We read that then took out some paper and Catherine drew a nucleus. She also drew a nucleolus and chromation and decided she'd draw RNA and DNA to represent what was in the chromation (nuclear proteins didn't make the cut). All the bits got labeled, the whole picture got cut out and we taped it on to our kraft paper cell.

We got to talking about the cell membrane after and decided that Rader's had made a bit of a bad comparison when it said the membrane was like a plastic bag. A plastic bag doesn't allow things to move into or out of it. So we decided skin was a much better analogy.

We'll come back to it over the next week and add organelles as we learn more about them. I have to admit I'm having as much fun as Catherine with this because when we covered this in high school I don't think I got a good idea of what each part of a cell really did in relation to the whole.