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Current time:0:00Total duration:10:00

Video transcript

supplants are freaking great because they have this magical wizard power that allows them to take carbon dioxide out of the air and convert it into wonderful fresh pure oxygen for us to breathe they're also way cooler than us because unlike us and every other animal on the planet they don't require all kinds of hot pockets and fancy coffee drinks to keep them going the only thing plants needed to make themselves a delicious feast the sunlight in water just some light in what Paula Deen can't do that and she makes fried egg bacon doughnut burgers I'm telling you this is the prize only good this is a different kind of magic but you know part of this is plants um and everything and it in fact everything that is in this McDonald's in fact everything she was ever eaten in your life is either made from plants or made from something to hate plants so let's talk about plants plants probably evolved more than 500 million years ago the earliest land plant fossils date back to more than 400 million years ago these plants were lycophytes which are still around today and which reproduce through making a bunch of spores shedding them saying a couple of Hail Marys and hoping for the best some of these lycophytes went on to evolve into scale trees which are now extinct but huge swampy forests of them used to cover the earth some people call these scale tree forests coal forests because there were so many of them they were so dense and they covered the whole earth that they eventually fossilized into giant seams of coal which are very important to our lifestyles today so this is now called the Carboniferous period simulated there because coal is man of carbon so they named the epoch of geological history over how face meltingly intense and productive these forests were I would give on my left eyeball 3 fingers on my left hand the middle ones so that I could hang loose and uh and my pinky toe if I were able to go back and see these scale forests because they would be freaking awesome anyway angiosperms or plants that use flowers to reproduce didn't develop until the end of the Cretaceous period about 65 million years ago just as the dinosaurs were dying out which makes you wonder if in fact the first angiosperms assassinated all the dinosaurs I'm not saying that's definitely what happened under it's a little bit suspicious anyway on a cellular level plant and animal cells are actually pretty similar they're called eukaryotic cells which means they have a good kernel and that kernel is the nucleus not nucleus and the nucleus can be found in all sorts of cells and all cells plant cells algae cells you know basically all the popular cakes eukaryotic cells are way more advanced than prokaryotic cells we have the eukaryotic cell me I'm the prokaryotic cell prokaryotic basically means before the kernel pro kernel and then we have the eukaryotic which means good kernel the prokaryotes include your bacteria and your archaea which you've probably met before in your lifetime every time you've had strep throat for example if you've ever been in a hot spring or an oil or something that they're they're everywhere they covered the planet there they cover you but like I said you carry oats have that separately enclosed nucleus that is that all-important nucleus that contains its DNA and is enclosed by a separate membrane because the eukaryotic cell is a busy place there's chemical reactions going on in all different parts of the cells important to keep those places divided up eukaryotic cells also have these little stuff doing factories called organelles because we decided that we've named everything something weird but organelles and they're suspended in cytoplasm continuing with the really esoteric terminology that you're going to have to know that a plasm is mostly just water but it's some other stuff too well basically if you want to know about the structure of the eukaryotic cell you should watch my video on animal cells which let's just link to it right right here plant animal cells are very similar environments they control themselves in very similar ways but obviously plants and animals are very different things so what are the differences in a plant cell that makes it so different from an animal well that's what we're going to go over now first plants are thought to have evolved from green algae which evolved from some more primitive prokaryotes and something plants inherited from their ancestors was a rigid cell wall surrounding the plasma membrane of each cell so this cell wall plant is mainly made out of cellulose and lignin which are two really tough compounds cellulose is by far the most common and easy to find complex carbohydrate in nature though if you were to include simple carbohydrates as well glucose would win that one and this is because fascinating fact cellulose is in fact just a chain of glucose molecules you're welcome if you want a jog your memory about carbohydrates and other organic molecules you can watch this episode right here anyway as it happens you know who needs carbohydrates to live animals but you know it's a real pain in the ass to digest cellulose so hands weren't born yesterday cellulose is a far more complex structure than you'll generally find in a prokaryotic cell and it's also one of the main things that differentiates a plant cell from an animal cell animals do not have this rigid cell wall they have a flexible membrane that frees them up to move around and eat plants and stuff however the cell wall gives structure to a plant's leaves roots and stems and also protects it to a degree which is why trees aren't squishy and I don't giggle when you poco the combination of lignin and cellulose is what makes trees for example able to grow really really thick and tall both of these compounds are extremely strong and resistant to deterioration when we eat food lignin and cellulose is what we call roughage because we can't digest it it's still you know useful for us and certain aspects of our digestive system but it's not nutritious which is why I like hearing a stick are really unappetizing and like your shirt this is all 100% plant shirt but tastes good but we can't go around eating wood like a beaver or grass like a cow because our digestive systems just aren't set up for that hello there other animals that don't have access to delicious donut burgers have either developed gigantic stomachs like sloths or multiple stomachs like goats in order to make a living eating cellulose these animals have a kind of bacteria in their stomach that actually does the digestion of the cellulose for it it breaks the cellulose into individual glucose molecules which can then be used for food but other animals like humans mostly carnivores don't have any of that kind of bacteria which is why it's so difficult for us to digest sticks but there is another reason why cellulose and lignin are very very useful to us as humans it burns my friends this is basically what would happen in our stomachs it's its oxidizing it's producing the energy that we would get out of it if we were able to except it's doing it very very quickly and this is the kind of energy like this energy that's coming out of it right now is the energy that would be useful to us if we were cows but we're not so instead we just use it to keep ourselves warm on the cold winter nights ow it's on me ow ah anyway while we animals are walking around spending our lives searching for ever more digestible plant materials plants don't have to do any of that they just sit there and they make their own food and we know how they do that they do it with photosynthesis another thing that plant cells have that animal cells just don't have are blessed it's the organelles that plants use to make and store compounds that they need and you want to know something super interesting about plastics they and their fellow organelles the mitochondria that generate energy for the cell actually started as bacteria that were absorbed into plant cells very early in their evolution like maybe some protists like cell absorbed a bacteria and it found that instead of just digesting that bacteria for the energy that it had it could use that bacteria that bacteria could create energy for the cell or convert light into lovely glucose pounds which is crazy nobody's really precisely sure how this happened but they know that it did happen because plastids and mitochondria have double membranes one from the original bacteria and one from the cell as it wrapped around it Oh huh anyway the most important of the plastids are the chloroplasts which convert light energy from the Sun into sugar and into oxygen which the plant doesn't need so just gets rid of it all of the green parts of the plant that you see the leaves the non-woody stems the unripened oranges are all filled with cells that are filled with chloroplasts which are making food and oxygen for you you're very welcome I'm sure other big difference between plant cell and an animal cell is the large central vacuole LAN cells can push water into vacuoles which provides turgor pressure from inside the cell which reinforces the already stiff cellulous wall and makes the plant rigid like a crunchy piece of celery or something usually when soil dries out Ora celery stalks sits in your refrigerator for too long the cells lose some water turgor pressure drops and the plant wilts or gets all floppy so the docq is also kind of storage container for the cell it can contain water which plants need to save up just in case and also other compounds that the cell might need it can also contain an export stuff that the cell doesn't need anymore like wastes some animal cells also have vacuoles but they aren't as large and they don't have this very important job of giving the animal shape so now let's do this let's just go over the basics of plant cell anatomy one they have a cell wall that's made out of cellulose and so it's really rigid and not messing around - they've got a nucleus in its own little baggie that's separate from all the other organelles this is basically the headquarters of any eukaryotic cell it stores the genetic information for a plant and also access the cell's activities director telling it how to grow when to split when to jump and how high that sort of thing animal cells have this kind of nucleus - but prokaryotes don't which is why they're stuck hanging around in oil wells and stuff three they've got plastids including chloroplasts which are awesome green food making machines and four they have a central vacuole that stores water and other stuff and helps give the cell structural support and so stack these cells on top of one another like apartments in an apartment building and you had a plant and all of these unique features are what makes it possible for plants to put food on our table and air in our lungs so next time you see a plant just just go ahead and shake its hand thank it for its hard work at its service
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