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Lecture Cell Cycle Mitosis asexual

Added Feb 03, 2016 •

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we're going to talk a little bit about mitosis today we've talked about asexual reproduction and the fact that it uses a process called mitosis some of your remember maybe talking about it middle school but let's refresh our memories what it means so mitosis is a type of cell division used for three main things asexual reproduction as we discussed earlier growth maybe adding new cells to a multicellular organism or repair multicellular citizens can use mitosis to repair dead cells that need to be replaced so just because we are a multicellular organism that normally reap is this by sexual reproduction it doesn't mean that we don't use mitosis in our bodies we use mitosis not for reproduction but we use it for growth you're growing teenage years younger years children adolescents you're adding new cells to your body to grow larger and you're also repairing dead cells that get worn out over so during mitosis there's a couple of things that happened but the main thing that we think about is that the DNA or genetic information is going to replicate which means sick in a cell is going to split in half it's going to divide up organelles and divide up the DNA into two daughter cells they're called not son cells but these daughter cells are identical to the parent and identical to each other so they're almost kind of if you would think of it as clones but these are natural clones with that said there was no genetic variation they're identical to each other we're going to talk about some of the problems that can come with having no genetic variation unlike with sexually reproducing organisms that have a lot of variety DNA remember is our hereditary material allow yes to pass on our trade store Offspring and it's organized into structures called chromosomes which contain or DNA are normal chromosome number and are normal who sells is referred to as to n n refers to the number of different types of chromosomes we have into essentially means that we have to copy the beach type so in the case of humans we have 23 different types of chromosomes and we have two of each kind and are normal body cells one came from her mother confirm our father for a total of 46 we often refer to this number as our diploid number die again refers to two so we have two copies of funset came from her mother one-set came from our father during mitosis that diploid number would be maintained you wouldn't what the number of chromosomes in half you would still have a total of two enter the diploid number of chromosomes does mitosis happen sucks a little bit extensive show you're going to probably need to pause in order to be able to draw each of the phases some of you may remember the phases from middle school turn this before we're going to refresh our memories because we're going to be talking about these faces again and revisiting them and comparing them when we talk about sexual auction in meiosis so let's look at each of the phases when it comes to mitosis we would have a normal parent cell and these structures inside the play s represent are chromosomes and in this case I have two of them colored red and I have two of them colored blue and that represents the two that came from the original are there cell if we're talking about an organism that reproduces sexually into that maybe came from the father sell that same thing from an organism that reproduce sexually been a case of an organism that completely reproduces asexually we remember there's no real mother or father but they still have two copies of each kind chromosome so are two and number in this case would be 4 we have a total of 4 chromosomes remember in humans we have a total of 46 what sounds are first phase which really isn't truly a phase of mitosis is called interphase during this phase we're really carrying out life processes but the cell is ready to go through cell division or mitosis and divide the DNA is going to replicate its going to make a complete copy of itself and its going to Terror for mitosis reproducing organelles and things like that the DNA at this point really is formed in something called chromatin you don't see it as nice little acts like structures of chromosomes yet but for visual purposes we're going to show them this way so now you can see that we made copies of our DNA I look like almost like a little axes with each other we have an original and copy so it almost appears like we have an 8 but we have two copies of each one are real first phase of cell division is called prophase during prophase if you're an animal cell the centrioles become visible and they produce these things the spindle fibers that the chromosomes attach to in the nuclear membrane is going to disappear during the next phase those chromosomes are going to line up in the enter attach to the spindle fibers the centrioles are going to go towards the poles stretching out those spindle fibers and we're I just see that they don't necessarily arrange themselves in a specific order it's relatively random but they line up in the middle so that during the next phase and a phase taken pull apart from each other evenly so that in the end each new cell gets one of each type of chromosome  MSN when they're lined up during metaphase they're attached to the spindle fibers and the chromosomes are still attached to each other the original and it's coffee and their attached biased Circle the centromere  during anaphase that original and it's copy split at the centromere the original goes one way the copy goes the other way of chromosome and we eventually have them starting to go towards the poles or opposite ends  our next phase telophase we see that if we're an animal cell we start pinching in this cell membrane we see that the chromosomes are towards each end but we can see the beginnings of a nuclear membrane reform at the end we divide up the cytoplasm in a process called cytokinesis and we light up the organelles the nuclear membrane completely reforms and you can see that we have a restored chromosome number of four we have to use of each of those chromosomes so we have a total number of 4 chromosomes in each cell identical to the parent identical to each other when we talk about mitosis we talk about the cell cycle a little bit just the cycle of phases and events that a cell goes through and its life  most of the time cells are in a phase called interphase used to be called a resting phase it really isn't actually resting then it's just not actively dividing it carries out all of its life processes during S phase of interphase most cells for the majority of their lifespan are in interphase during cell division where it's going through prophase metaphase anaphase 2 play some cytokinesis the active parts of mitosis it's very short period of time for most cells a lot of cells can carry out this process within about a half an hour I'd like you to try to think of a way to try to remember the phases of mitosis some of you guys might have remembered the ape Matt IPM 80 taking the first letter of each of the phases but remember interphase technically isn't a phase that we talked about during mitosis is not included even though we need to discuss it so maybe you can come up with your own way to remember the order of each of the phases and maybe you want to include cytokinesis the division of the cytoplasm  what are the issues with the cell cycle and we'll talk about this a little bit more in detail and class is that if this cell cycle isn't regulated well and gets out of control and the cells just keep dividing and dividing and no longer have control of division we end up with a process of can't we'll talk about the control of this and how genetics can come into play during cancer but just understand that when the cell cycle loses control and relation that's technically considered cancer and that's it for me to do tonight that you're familiar with what happens in each phase

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Lecture Cell Cycle Mitosis asexual

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