2015 AP Biology free response 4

Both mitosis and meiosis are forms of cell division that produce daughter cells containing genetic information from the parent cell.

Part A: Describe two events that are common to both mitosis and meiosis that ensure the resulting daughter cells inherit the appropriate number of chromosomes.

All right, so really we just want to, well, what are two commonalities between the two? Well, I can think of a bunch of them. You could start off saying, well, DNA replicates before going into either of them. So, DNA replicates before either. Before either, you could say, well, the chromatin condenses into chromosomes in both of them. Chromatin condenses into chromosomes. You could talk about chromosomes getting aligned near the center of the cell, attaching to fibers. You could talk about, we could talk about cytokinesis splitting the cells. So, cytokinesis is involved in the creation of separate cells.

In general, your meiosis one has a lot of analogs with mitosis. You could keep looking, keep digging deeper, and listening more and more. They just want me to describe two events. I've already described three. Well, I'll leave it at that for now. In general, before you take the AP test, mitosis and meiosis are good things to know in detail because you might see questions like this on the free answer section, or they're likely to show up in the multiple choice section as well. But I think this is sufficient for part A. We've described at least two events that are common to both mitosis and meiosis. If you have extra time, you might try to list more.

Part B: The genetic composition of daughter cells produced by mitosis differs from that of the daughter cells produced by meiosis. Describe two features of the cell division process that lead to these differences.

Well, maybe the most obvious one, the biggest difference between them is mitosis. Mitosis involves one division. It involves one division. Meiosis involves two. Meiosis involves, involves, not involves, involves, involves two. This leads to two daughter cells from mitosis and four daughter cells from meiosis. That looks, that's a pretty big difference between the two.

Another big difference, and this is related to this, because meiosis has an extra division, has an extra division, but DNA replicates once, like in mitosis. The daughter cells from meiosis have half the number of chromosomes. They have a haploid number of chromosomes. The daughter cells in meiosis have a haploid number of chromosomes.

So, we say mitosis daughters have diploid number, and these are probably the two strongest differences. But you could talk about other things. You could talk about crossing over occurring in meiosis but not in mitosis. You could talk about the separation and independent assortment of homologous chromosomes that you have, each member of a homologous pair that you have in meiosis that you don't have in mitosis.

So, there's a bunch of things you could talk about, and you can go into arbitrary detail. It's nice that they only have to list two in each of these parts of question four.