Life Science - Cell Structure and Functions

 welcome back to educator calm this is the life science course and today's lesson is on cell structure and function our objectives for today will be number one what are the names and functions of organelles number two what is the importance of a nucleus in a cell and number three what ourselves tissues organs and organ systems let's start with talking about the common cell traits all cells are the smallest unit of life you can't get smaller than a cell and still be able to hold all the functions necessary for life to occur all cells have certain structures they have a cell membrane and that is the outer covering of the cell that holds all of its contents and then all cells have what we call cytoplasm cytoplasm is basically the jelly-like fluid inside of the cell it basically gives the cell its shape and it also holds or suspends all of the structures within the cell it also holds the hereditary material that is inside of the cell that is copied and when that cell is ready to reproduce itself that hereditary material is copied inside of the cytoplasm now there's two types of cells there's prokaryotes and there's eukaryotes prokaryotes are the difference between the two or that the prokaryotes do not have membrane-bound structures meaning anything that is in a prokaryotic cell is free-floating what we call free-floating and does not have a membrane certain examples of prokaryotes are bacteria yeast and protists these are of course are the very simple structured cells they're easy to copy and they're easy to reproduce because they don't have any membrane-bound structures and they're very simple then we've got the more complex prokaryotes these cells do have membrane-bound structures and they're more of course more complex and examples will be fungi plant and animals now here are pictures of the eukaryotic cell in the prokaryotic cell and this is just to show how much more involved in more complex of eukaryotic cell has as far as the structures with them because it has to do more function than a prokaryotic cell alright let's talk about cell shape now all cells come in different shapes and sizes and for the most part the cell shape depends on the function of that cell so for example in the human body we have nerve cells and nerve cells transmit messages from parts of the body to the brain and so those nerve cells must be very long because they transmit those messages and through long distances so this would be an example of a nerve cell or what we would call a neuron which is the name of a nerve cell and as you can see the neuron has a very long what we call an axon it's got a kind of like a head to it where what we call the nucleus or the brain of the cell is up at the top but it's got all these branches to that basically branch out to different parts of the body and so that is the reason why you can send messages from your toe all the way to your brain because of these long neurons and then we have like the egg a human egg cell found in the female human body in the ovaries and it's actually the largest cell in the human body starts off as a largest cell in the human body and then it continues to grow through a process we call mitosis which is just part of cell division but basically that human egg has a very large nucleus it has a lot of cytoplasm it has quite a bit of what we call a structure called mitochondria which basically helps the cell to provide energy for the cell and that's because that human egg will soon be a human over time if it's fertilized so that's the reason why it's got to have a pretty large start out as a pretty large cell and then finally have a very simple cell in the human body the blood cell now the whole purpose of the blood cell is to carry oxygen so it's the blood cell doesn't have a large nucleus or large numbers of different organelles what we call organelles or different structures inside because the most most of the body or what most of the inside is going to be there to carry oxygen so it's very simple

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