Originally posted by AThousandYoung
I'm a TA in such a class. These questions got me.
1) Are teeth made of cells?
2) Is there pigment in tree bark making it brown?
3) Why don't animal cells have cell walls? (I have an idea, but am not sure).
4) Are there blood vessels in bones (e.g. in the marrow)?
5) If you break a piece of celery or a carrot in half, do you rupture cells (vs. breaking cells apart from one another)?
6) Why do starving people have big bellies?
1. Yes, so are bones, so is every part of our bodies.
2. Yes, the pigment makes the bark brown. However, this is not "melanin" that makes our skin brown or tan. The "brown" is just a color. Whatever "the pigment", it's the coloring substance.
3. Plant cells have walls. Animal cells have "membranes." Think of it this way: Plants are immobile (in the animal sense), and the "structure" benefits them. Animals "move." There are many more fundamental biochemical principles involved. These are 7th grade answers.
4. Yes, there are blood vessels in bones. In fact, if a doctor or a nurse or a paramedic cannot put a needle into a vein, they can insert one into the bone - right into the marrow - and give fluids into the veins that way.
5. A few celery cells will break, sure. Just like a swift kick in the bum kills a few muscle cells. Not enough to matter.
6. Starving people have big bellies from gas bloating, or poor nutrition, bad nutrition balance. A big belly is not a sign of health. Those starving people have underdeveloped other parts of their bodies.
Caveat: All of these answers are just off the top of my head. I don't have a clue if i'm right or wrong, except on a few of them . .like the bones and cells.