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Biology library
Course: Biology library > Unit 35
Lesson 1: 2015 Free response worked examples- 1a-c, Responses to the environment
- 1d-e, Responses to the environment & natural selection
- 2a-b, Cellular respiration & common ancestry
- 2c-d, Cellular respiration & cell compartmentalization and its origins
- 3a-b, Phylogeny
- 4a-b, Meiosis and genetic diversity
- 5a-b, Responses to the environment
- 6a-c, Population ecology
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4a-b, Meiosis and genetic diversity
Commonalities and differences between mitosis and meiosis.
Want to join the conversation?
- It seems to me that at, there is just a clarification of the first point and not the second feature out of TWO because the number of cells doesn't affect their "genetic composition" mentioned in the question asked. Is it my mistake, or are, for example, conjugation and crossover more suitable things to enlist? 4:06(8 votes)
- Why don't we say that metaphase I and anaphase I are common EVENTS to both and ensures that correct numbers of chromosomes appear in daughter cells as the right number of chomosomes join to centrioles etc(5 votes)
- We can and its a good suggestion but it's probably not seen as a valid answer or will not be accepted in the mark scheme, for that particular question.(2 votes)
Video transcript
- [Voiceover] 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 wanna, 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, chromatin condenses, condenses into, into chromosomes. You could talk about chromosomes form, getting aligned near
the center of the cell, attaching to, to, to fibers. You could talk about, we could talk about cytokinesis. Splitting the cells. So, cytokinesis, kinesis involved, involved in creation of separate cells. Creation of separate, separate cells. In general the, your meiosis one has a lot of analogs with mitosis in general. You could keep looking, keep digging deeper and
listing 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. And then 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, involves one division. Meiosis involves two. Meiosis involves, involves, not inolves, involves, involves two. This leads to two daughter cells from mitosis, and four daughter, daughter cells from meiosis. Meiosis. That's a pretty big difference between the two. Another big difference, and this is related to this. Because, because meiosis has an extra division, has extra division, but DNA replicates once, like in, 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, number of chromosomes. Chromosomes. So, and we could say, mitosis daughters have diploid, 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 sortment of homologous chromosomes that you have. Homologous, 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 could go into arbitrary detail. It's nice that they only have
to list two in each of these, in each of these parts of question four.