[Music] hi it's Mr Anderson and welcome to biology Essentials video number five this is on the essential characteristics and how they're conserved uh today I'm going to be talking about life uh this right here is a tree of life a circular tree of life and you can see that this tree of life is going to Branch over to here these would be like the ARA um these would be the ukaria uh we would be humans would be right here if I can read that right uh these are going to be the bacteria that go over here and so we have this tree of life that tells us a few things number one we're more related uh to ARA than we are to bacteria um but it also shows that there are certain characteristics that are shared by all of life in other words all of life has DNA and so that must have originated very early in this tree of life and so today what I'm going to talk about are essential are essentially um characteristics essential characteristics in other words things that are required for life and how they're conserved or how they stick around um through time uh if we kind of plan this out uh I this is what I want to talk about I want to talk about three things and how they're conserved uh the first one would be the genetic code and that's DNA uh next thing is the central dogma and that's uh how DNA eventually makes um RNA and how RNA make proteins and then make you and then some metabolic pathways uh metabolism is the sum of all chemical reactions inside life and there are some really fundamental things that you may not know that are found within these three groups so these would be the three domains we call that bacteria ARA and ukaria and so all life fits into one of these three categories and so these three things are conserved or found in all of life we'll also find that we move up that tree a little bit when we get to the ukari there are going to be characteristics that are shared within them as well uh and so as we go farther farther and farther and farther up that uh tree of life we find more and more characteristics and and we get finer and finer detail as we move our our way up so uh let me quit talking about what I'm going to talk about and actually do it let's start with the first one and that is the genetic code and that is DNA so you should be familiar with this that double helix structure um most people know what DNA is but they don't necessarily know what it does um an example would be this um a jellyfish right here scientists were able to take a uh Gene out of a jellyfish that makes a glowing protein that allows that jellyfish to do well deep in the ocean uh they were able to take that DNA and put it into a bacteria this is a really cool picture it's a petri dish where a scientists put different genes inside the bacteria to make them glow in this case it's making it grow glow this kind of a a green color we've also been able to put it inside fish and make fish that glow green and so the genetic code is found in all of life in other words it's Universal we've never found anything that doesn't use uh DNA as its genetic material or RNA uh if we talk about viruses and so this is found in all of life and it's also interchangeable which is cool we can take the DNA back out of here put it in here put it back we can put it anywhere and DNA is going to be Universal and so that suggest that all life uh comes from this one common ancestor next thing is the idea of uh the central Dogma central dogma you may not be familiar with that but you should know what it is um Watson and Crick were the people who got credit for um diso discovering the structure of DNA but this guy right here Francis Crick spent the next then uh 10 years figuring out well the Machinery behind the DNA and so what it actually does and so he summarized it right here and so essentially what happens is DNA can copy itself we call that DNA replication it then through transcription makes RNA RNA makes proteins and a protein eventually uh makes you and so every part of you is made up of proteins and the result of protein action and so um all life goes through the same mechanism in other words in bacteria they have the genetic material as DNA they make RNA out of it and then they make Pro proteins now the way that they do that the ribosomes that they use are a little bit different but the mechanism is is going to be exactly the same and so we've never found life that doesn't utilize this central dogma remember you pass your DNA on and then the cycle can begin uh again and the last one is metabolism metabolism remember is how we kind of make use of the energy that that's given to us and so it summarizes here in other words we as humans and fungi and and a lot of bacteria can take in organic material and oxygen uh we then make carbon dioxide and water this is called cellular respiration and then there are certain producers that can actually make that again whereas plants are making sugar so they can actually break it down but regardless of all of that there are a few things that are found in all living organisms and so if you know what a DNA is and you know that all life has it you should also realize that this is the coinage the energy coinage that all life uses as well and so if I ever heard that we discovered life on some other planet I want to know what's the hereditary material and then what is it how is it making its energy what's it using for metabolism and so the fundamental ways that we utilize energy or get energy and make ATP is through gsis KB cycle and oxidative phosphorilation so all life uses one of those and either anerobic or aerobic respiration and so bacteria fungi whatever we're making ATP and we're using the same fundamental metabolic pathways and what does that suggest going way back to that tree of life that it originated very early in the life uh on our planet and it's been passed down uh through time but we'll get more into detail on on respiration photosynthesis a little bit later now if we go to the next group um so remember we have if I were to sketch it out we have the breakoff of bacteria domain we also have the branching off of ARA these ancient life and then finally we have ukaria and that's what you are and actually everything on here from animals all the way over to fungi down in here to unicellular organism and plants and all these things are ukari now they are a different kind of a cell and so what do you know about a ukari it actually if I remember right cararo comes from egg and so the best way to think about um a eukaryotic cell is that it has a nucleus so it has a nuclei on the inside where it stores its DNA but how did we go from these simple cells to cells that are eukariotic and have a division of labor inside the cell itself well there's actually two ways that we did that and two characteristics that I chose to talk about related to UK carots tell us how we got there so let me clear that off and get to the endomembrane system and so the first way that cells move from very simple cells to more complex cells well if you think about it let's say I have one cell this is really simple but how can I make that more complex well a really simple way to make that complex is to have it f in on itself and if I have it fold in on itself now I have an increase in surface area and so I can I can do other jobs and so we have a number of things so you know the gogia apparatus endoplasmic reticulum lomes vesicles all these things are made we think from the infolding of this What's called the endomembrane system or a membrane on the inside now what's interesting is that we can actually look at proteins on the outside of the cell and proteins on the inside of the cell oops let me go back for per second and proteins on the inside of the cell and we find that they'll actually be reversed in other words ones that on the outside of the cell will now be let me get this right on the outside of this and vice versa here so we also have some strong molecular evidence as well to show that this infolding has occurred and so that's a common characteristic this endomembrane system of all eukariotic cells and then another example would be uh organel themselves the two specific ones that I'd like to talk about are the mitochondria which we use to get energy out of our uh food to do oxidative phosphorilation and get as much ATP as we can and then the chloroplast which is used in plants and a lot of photosynthetic UK carots to actually take energy from the Sun and then use that fix carbon now what's interesting about these two is that they are not formed we don't think by an infolding of the membrane they're not part of that endomembrane system so that's not them these actually were formed by endosymbiosis and so what we think is that the um mitochondria was a bacteria once on its own it was living in CL close proximity to these early eukaryotic cells and then eventually started Living inside and so it's actually a cell within a cell now what kind of evidence do we have because that seems crazy that this is actually occurring well if you look inside here we actually have DNA inside of mitochondria and and so they're actually reproducing by binary fision on their own and they have a lot of properties that are very similar to um bacteria and we think Chlor plast got into plant cells in the same exact way and so they're kind of hijacking or living inside of us at this time so it's a cool way that we can get complex UK carots uh and so those are some common characteristics of um of ukari and I guess the whole General point of this video podcast is that if you come up with a solution that solution is going to be passed up the tree of life there's no way to we could step back and say hey let's find a new genetic information let's use something else that decision was made billions of years ago and so I hope that's helpful