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Main content
Current time:0:00Total duration:6:50
AP.BIO:
ENE‑2 (EU)
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ENE‑2.K (LO)
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ENE‑2.K.1 (EK)
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EVO‑1 (EU)
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EVO‑1.A.2 (EK)
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EVO‑1.A.3 (EK)

Video transcript

when we want to categorize life as we know it at a very high level we can categorize it as either eukaryotic you carry otic or as a eukaryote you carry out or as a prokaryote pro pro carry out and the largest distinction between a eukaryote and a prokaryote are membrane-bound structures that eukaryotes have that prokaryotes prokaryotes don't have and the most noticeable of which is a membrane-bound nucleus so in a eukaryote the genetic information is going to be inside a membrane-bound nucleus so this right over here this is the nucleus this is the nucleus and you have your genetic information inside it you have your DNA here for a prokaryotic cell you're going to have your DNA and it might be bundled up into a section of the cell we would call that a nucleoid but it's not membrane bound so let me write this down no no membrane membrane membrane let me write a little membrane bound membrane-bound nucleus but that's not just the that's not the only distinction between eukaryotes and prokaryotes although it's the one that's most noted in fact the word eukaryote the carry out part comes from the Greek for nut or kernel so let me make this clear so this is referring to a nut a nut or a kernel or a kernel while prokaryote means before the nut or kernel so we don't see and you know I guess you could think of the nut or the kernel as the membrane bound structure especially the membrane bound nucleus over here but that's not all eukaryotes will also have other membrane-bound structures that you will not see in prokaryotes for example you will tend to see mitochondria Myto mitochondria in a eukaryotic cell both plant and animal cells but you won't see it in a prokaryotic cell and there's other types of membrane-bound structures you could see things like like Golgi apparatus this over here is a micrograph of a eukaryotic cell and you see the Golgi apparatus right over here which helps package proteins you see a micrograph of mitochondria this is a micrograph of the nucleus so this right over here is the nuclear nuclear membrane and then you see all the genetic information it's all spread out it's in chromatin form right over here but you see it's especially densely packed right over here and we've also depicted in this so right over there so this is all the DNA in chromatin form but this part that looks extra dense or dark in this micrograph right over there we call that the nucleolus we call that the new nucleolus and we now know that this is where ribosomal RNA is being produced and ribosomal RNA that part that forms part of the structure of ribosomes which are essential in the translation or I guess you say the construction of proteins based on the information in mRNA and we can go into a lot more depth in that in other videos so this is this these are ribosomes right over here and they're made up of ribosomal RNA and they're also made up of proteins and so this nucleolus over there that's where that's where that's happening that denser part of the nucleus so the key distinction eukaryotic cell you have a nuclear membrane bound in nucleus you have other membrane-bound structures like mitochondria in fact there's some theories and mitochondria first evolved as as prokaryotic organisms that eventually lived in symbiosis inside of eukaryotic inside of a larger eukaryotic cell and then the other distinction is that in eukaryotes the DNA tends to be in multiple strands so the DNA if you were to kind of straighten it out it would be in multiple strands well in a prokaryote the DNA tends to be the DNA tends to be circular can be all it can be all flipped around and whatever else but at the end of the day it would be circular DNA so those are the three core distinctions nuclear membrane other membrane-bound organelles like mitochondria and Golgi and the Golgi apparatus and then you also have single trans multiple single strand of DNA versus circular DNA other things is that eukaryotes tend to be larger while prokaryotes tend to be smaller and they tend to be simpler so now that we know the key distinctions what are examples of eukaryotes well eukaryotes include most of what we interact with on a daily basis or we think we're interacting with on a daily basis this includes all multicellular organisms so multicellular multi cellular organism so I'm thinking animals plants fungi it includes protists this is a Paramecium right over here this is eukaryotic it's going to have a membrane bound nucleus and other organelles this right over here these are onion root tip cells so these are plant cells and you can actually see it's been stained you can actually see the membrane bound nucleus here and this is actually a cool picture because you can see these cells and different at different stages of mitosis which is interesting animal cells the things that make you you you are you carry otic so what is prokaryotic well bacteria is probably the most common example of that bacteria right over here these are Pro these are prokaryotes and lesser talked or are things the thing that's talked about a lot less is archaea and archaea people initially thought that these were a form of bacteria that just lived in very extreme conditions but now they know that it's a completely different domain of life our archaea archaea and so when we think about the domains of life people the current the current thought is that you have bacteria here bacteria here you have archaea you have archaea are k'i and then you have and then you have eukaryotes I'll do it there and then you have eukaryotes you carry oats and these are things that have all the the traits that we've talked about and so these include plants and animals and fungi and you cellular eukaryotes like protists and things like that and so if we once again just high-level we would consider these ProCare goats and these of course are the eukaryotes so hopefully that gives you a good overview of things