DNA Structure | DNA Function | Cell Biology | Part 1

expression with the basic concepts related with genetics there was a time that when doctors knew very less about the genes and chromosomes and it was considered a very difficult topic but now they have discovered a lot about the genes about the chromosomes how do they function what is their importance now it has become one of the most fascinating medical sciences and most interesting to read initially in our lectures we will be discussing the very fundamentals and very basics once we have covered the basics then we'll go to the advanced concepts of genetics when we are talking about the very fundamental all of you know that life is primarily dependent all the life programs are primarily stored in dna the point number one is that all the life program is stored in dna for example why a monkey is monkey because it has different dna than you and why onion is different from you because onion has different dna than you basically in a fertilized ovum in a fertilized ovum all the genetic material which is present over there that have all the complete program to make structurally and functionally complete organism right and all that programming is basically in the molecule of yes please dna right so you can say the master plan of life for every organism is present in dna and then dna expresses itself in the form of rna you can say master plan is in dna and from the master plan cells make functional copies the functional copies of dna are rna and from the rna we can make proteins from the rna we make proteins different rna help in formation of proteins and once you make the proteins you know some proteins are structural proteins some proteins are structural proteins and there are other proteins which are functional and regulatory proteins right now in a particular cell dna will express certain rnas and rnas will make particular type of proteins and those proteins will determine the structure of the cell as well as function of the cell is that right so it means that dna determines rna rna determines the type of proteins present in a cell and types of cell determine what kind of organ will be made and assembly of the organs will determine what type of systems will be made and how the system structurally and functionally work determines which organism you are right so to understand the genetics our initial lectures will be focusing on dna right today our main discussion will be what is the structure and function of dna right now when we talk about dna any one of you will define what is dna any one of you will define please what is dna you are allowed to make mistakes i don't mind it even those people who see in the recording they won't mind it right so anyone will define what is dna yes please yes kashif dna is deoxy ribonucleic acid yes okay this is one way to explain it anything else better than this definition what is dna dna is a polymer of linear polymer of nucleotides that's so simple what is dna write it down dn is a linear polymer of nucleotides that's it again i will repeat what is dna dna is unbranched linear polymer of nucleotides for example that if i say that this is a string of dna a strand of dna it must be made of many what are these things nucleotides so it means to understand that how dna is made actually we must understand how nucleotides are made let me repeat it again i was saying that the master plan of life is present in dna right and dna makes the functional copies which are which are called rna and rna expresses eventually itself in proteins and different rnas make different structural and functional proteins is that right is that clear and that determines organism structure and function so it means organism all the structure and function is primarily dependent on dna right so initial discussion is about dna now what is dna dna is a linear polymer of nuclei and branch or linear polymer of nucleotides or we can say many nucleotides put together i'm making a long chain what is it dna or rna depending upon the type of nitrogenous bases and type of sugars right what type of pentoses are used now before we really go into detail of what is dna what is the relationship of dna with the chromosome what is the relationship of dna with the genes what are alleles right before we delve into that detail we will discuss what is the nucleotide what is the basic structure of nucleotide right now let us start discussing about what is the nucleotide you know if we have many nucleotides we can make a molecule of dna but first we must say or rna you can say if we have many nucleotides we can make nucleic acids nucleic acid that dna and rna now we'll try to make a nucleotide what is nucleotide actually let's suppose we give the duty of making dna to this lady she needs some raw material to make dna let's suppose hypothetically we are going to synthesize dna by simple elements the first thing which we require for dna synthesis is the first raw material we need is nitrogenous bases nitrogenous bases right now to make the dna there are two types of nitrogenous bases they are double ring structures and the single linked structures about to make a molecule of dna first of all we must have nitrogenous bases then what are nitrogenous bases these are nitrogen containing carbon rings what are nitrogenous bases nitrogen containing carbon rings now there are two types of rings there are double ring structures and there are single link structure double ring structures are called purines doubling structures are called purines and single ring structures are called yes please pyrimidines right so we should have nitrogenous bases there are two types of nitrogenous bases larger nitrogenous bases with double rings smaller nitrogenous bases with single ring double ring structures are purines single linked structure that pyrimidines is it clear now there are two types of purines yes please the two types of purines very good adenine and right you can say we can present them like this these are double rings in the same way the two types of pyrimidines which are used in dna yes please cytosine and thiamine or thymine thymine thy not th i a that is a vitamin right now look purines are adenine and govanine pyrimidines are cytosine and thymine is that right so in this way the raw material we have provided her with four raw material we have provided her with adenine we have provided her with guanine we have also provided her with cytosine and thiamine but this is not enough to make dna right the next point is once you have these four nitrogenous bases these nitrogenous bases should be fused with sugars sugars with five carbons such sugars are called pentoses so second thing they need is pentoses right it has nothing to do with the pants pentoses right now pentoses are basically special type of sugars which are five carbon the one carbon here another here here and there is another carbon here and of course this is not carbon point this is oxygen right carbon number one two three four and this is carbon number five right now if at position number two and carbon position number three if they are hydroxyls then what is this sugar yes please ribose very good this is ribose but if you puncture this from here oxygen has gone out right and there's no hydroxyl only hydrogen here then it is called deoxyribose so you can say that this pentose sugar with double hydroxyls as position number carbon number two and three is used for rna because if ribose is present the molecule will become rna and if you remove this oxygen from here and then at carbon number two its only hydrogen molecule become deoxyribose oxygen has gone out so it is deoxyribose and if in a nucleic acid this sugar is used deoxy sugar is used then that nucleic acid is going to be dna that is going to be dna am i clear now the madam has nitrogenous bases and night madam has sugar is that right purines pyrimidines and deoxyribose and what she is going to make dna so next step is that she should fuse sugar and nitrogenous bases she should fuse sugar and nitrogenous bases let's suppose we make these sugar molecules and we will fuse them with yes please nitrogenous bases let's suppose here we have added adenine here we have on the side added yes govanin here we have added yes cytosine excellent and here we have added thymine now what you see on the side of the sugar we have nitrogen nitrogenous base let me repeat it what we have done this was sugar molecule on the side of the sugar molecule we have added nitrogenous base so such sugar molecules which have nitrogenous base on the side these nuclei these molecules are called nucleosides these are called nuclear sides so next time what are nucleosides nucleosides are pentosis sugars right and these sugars attached nitrogenous bases on the sides right what are nucleosides these are sugars pentose sugars with nitrogenous bases attached with them now this is nucleosides the name of the nucleosides look here when adenine bind with the sugar it is no more adenine it is adrenocine what is it this is adenosine right when go on in bind with the sugar then it is just please guanosine excellent and when cytosine bind with the sugar this is called yes please citrine and when thymine is fused with the sugar this is called thymedine excellent thyme bean so what we have learned that madam took nitrogenous bases fused them with sugars is that right you put the pentoses on the nitrogenous bases and now they are called nucleosides different type of nuclear sites are adenosines guanosine citrine thymidine now the basic difference guanine is just nitrogenous ph but guanosine is nucleoside adenine is just nitrogenous base adenosine is nucleotide nucleoside now these are nucleoside now but you know dna is made of nucleosides and nucleotides so it means now we have to convert the nucleosides into nuclear tides she is very near to make a dna now she is going to convert nuclear sides into nuclear tides right now how do you do that answer is very simple that to this nucleoside you add phosphates you know phosphates are energy molecule more phosphates attached energize the molecule right now let's suppose this is adenosine and with this adenosine she has okay this is adenosine molecule right and this adenosine molecule is nuclear side now at point number five you know carbon fiber is at the top we put a phosphate we are putting here a phosphate when this nucleoside is at tied up with a phosphate it is called nucleotide so what are nucleotide nucleosides tied up with screwed up with phosphates right so when nuclear sites attach with the phosphates they will convert into nuclear tide so now you see how many types of nucleotides you can make right now yes your mathematics is good all of you have passed the primary class good so this is nucleotide with adenine this is nucleotide with guanine here's the nucleotide with yes cytosine here's the nucleotide with thymine is it right now and why the nucleotide because their fifth positions are having attached with them yes please phosphates they are having phosphates right now these are nucleotides now what should be the name of this nucleotide yes please kashif excellent it is an adenosine molecule with one phosphate what is this adenosine monophosphate and if we add one more adenosine diphosphate and if we add one phosphate more adenosine triphosphate and then this molecule is called atp adenosine triphosphate molecule i told you phosphate molecules are energy rich now this adenosine in adenine with sugar adrenocine with monophosphate one more diphosphate one more triphosphate adenosine triphosphate it has phosphate bonds here and when these bonds are broken lot of energy is released so this is energy rich compound is that right so we can say that nucleotide may be monophosphate or diphosphate or triphosphate of course what about this who will put the name for this one uh yes please gtp gonna seen try phosphate and if we have added phosphates here also right this is another nucleotide and this is yes please cited in triphosphate and if we add phosphates over here and now what is this molecule thymidine try phosphate is it clear so we'll just recap it we are going to make dna initially we said what is dna dna is basically basically a polymer of nucleotides right dna the unbranched linear polymer of nucleotides is that right now we are going to make what are nucleotide right we started with very basic that to make the dna we must have nitrogenous bases there are double ringed end single ring double ring door single lingar pyramiding double ringed are adenine or guanine and for dna single lingar cytosine and thymine but if there is rna then in place of thymine there is uracil excellent then there is uracil but not in dna now if you have these four nitrogenous bases just add these bases on the sides of sugars pentose sugars if carbon number two and three both are having hydroxyls then this is ribose sugar if oxygen is out of fat then it is deoxy ribosome then it is deoxy ribose now once you have deoxyribose sugar you can add with it nitrogenous bases when nitrogenous bases are added to this side then this complex should be called nucleoside so what are nucleoside nitrogenous bases added on the sides of pentoses is that right now when adenine is added this become adenosine guanine is added guanosine cytosine cytosine is added citrine thymine is added thymine and these are different types of nucleoside once you have the nucleosides then if you add phosphate to the carbon number five you know this was the carbon number five at this point we add the phosphate so at the carbon number five right when you add the phosphate here or here when you tie up the phosphates here then these nucleosides are converted into nuclear types so we can say these are different types of nucleotides right and when these nucleotides are made into a long chain then these nucleotides are making dna is that right now we'll make for our functional purposes we'll make a simple diagram of nucleotide let's suppose a typical nucleotide is like this yes please what is this component of the nucleotide sugar what is this component nitrogenous base and what is here phosphate now we can see one thing for every nucleotide this end is five and you know this is carbon number five and what is this end three and every nucleotide has 1 5 and other 3n we can make a simple diagram for us we can make a simple diagram for us let's suppose i make a phosphate like this okay if i make this lady like this what was the difference it is not shut shut is like this actually japanese make the ladies like this and i will not mention the nations which make the ladies like this right but anyway don't think of ladies right now let's talk about dna so this phosphate is like this right yes now you tell me what is this sugar molecule is just made like this and here is what nitrogenous space and this is their doll this doll is nuclear diet so it means many such dolls put together will make one molecule of dna so today onward when someone tell you their nucleotide you must think of this doll this is a doll with sugar on the side of it nitrogenous bases having a head end with phosphate and this doll is head and end foot end head end is five end and foot end is 3 end is it clear now what is the basic structure of dna let's talk about this nitrogenous species with sugars are nuclear sites with phosphates and nuclear types and when nucleotides are making linear polymers this may become dna or rna now yes please do you have any questions uh we cannot know what type of sugar there is you are very right actually that is why with the dinosaur in the right d then it means it is deoxy and if d is not written intelligent people know this is not deoxy right okay now we come let's suppose there are many dolls like this there's one doll this is guanine then there's another doll cytosine then there's another doll thiamine then there's another doll and this is adenine right now if this dollar attached with each other this is a piece of single strand of yes dna this is a small piece of single strand of dna as i told you what is dna dna is simply a polymer of nucleotides is that right any question up to this no now there's one very basic principle that when we are going to make dna for example there are enzymes in our body which work together to synthesize dna to start a dna first of all we will go in detail later how exactly dn is replicated but right now just for the basic concept let's suppose this is our first nucleotide yes what is this end 5n what is this end 3n right she has already made many nucleotides she has to make a linear polymer and then these nucleotides will convert into a string of dna now there's a rule let's suppose that we have to put the next nucleotide should be with cytosine actually when dna synthesis is going on lot of you can say abundant supply of all different type of nucleotides should be there any with adenine with go on in with yes please cytosine with thiamine all these should be present in abundant amount when a cell is replicating dna it means it has to put a lot of nucleotide in a chain form so cell fluid must be rich in these molecules but remember if this is our first molecule right and suppose this is the next molecule which is supposed to come and fit here now there's a principle it is well established right this molecule is going to this one right or we can say this particular nucleotide is going to this one and get attached with it so it means this is the needy one to be fitted here it should take some gift along with it you know it even nucleotide know the social life and is this nucleotide if you want to make a relationship with it then it has to take some gift gift of what currency energy phosphates one phosphate is not enough one phosphate is not enough there should be three phosphates if it is having only one phosphate or two phosphate it will not be accepted at this point right it means none of them should be monophosphate all of them should be yes triphosphate right so when in the cell dna synthesis is going on the nucleotide which are present within the cell these nucleotides should be monophosphate diphosphate or triphosphate just please all of them should be triphosphate and because triphosphates are rich in energy because these triphosphates are rich in energy so they can be accepted over here this is point number one they they should be having abundant supply of all the nucleotide to be utilized and all of them should be in the form of try phosphate now another thing not only should bring the gift this is the nucleotide which wants to fit here right it has to put its head in the feet of this very primitive behavior seen in dna formation that the incoming nucleotides should put its head bow down on the feet of already established dna strain so it means the five end of this should attach with the free end of the established one right now let's talk about that has been brought here and these are the gift molecule right and this is also suppose adenine this was the original this is the this one which has come now enzymes will utilize the energy of these phosphates and establish a relationship between these two enzymes will enzymes which make the polymers of dna enzymes need energy here so this triphosphate will bring the energy and these two will detach away and energy will be released only these two will be removed these are very sad you know these are very very sad this is a pyrophosphate unit these are pyrophosphate unit so from triphosphate para pyrophosphate unit is released and during this process the energy which is released that help to establish a bond between the yes three end of the established chain and five end of the incoming nuclear tied and now energy has been spent here is it going to be a strong bond a weak bond strong bond investment is there atp has been utilized phosphate energy has been utilized right now these two have attached now let's suppose this one has to come into this same process will repeat that that will put its five end in the feet of this already and now again what will happen this is guanine and again pyrophosphate is released am i right and a bond is made in between them what is the name of this bond yes anyone what is the name of this bond very good phosphor diester bond so we can say in dna formation the nucleotides are held together by these red bonds these red bonds are phosphor diastoles these are phosphodiester bonds now these phosphodiester bonds help the dna formation how they help the nucleotide to be polymerized with each other of course now you are going to tell me now next nucleotide is in the line again this incoming nucleotide should be monophosphate by phosphate or triphosphate triphosphate and with that three end of the established chain and which end will come five and they will bind with each other here is cytosine and what is again released energy and pyrophosphate and that energy is utilized to build a bond between the three end of one and the five end of the incoming and again this bond is called phosphodiester bond right and so and so forth so what really happens that another let's suppose thymidine is there again pyrophosphate is released and again there is a three five bond and what is this bond again please repeat phosphor diastereo bond again tell me is it strong bond or weak bond strong bond right because later on we'll see that this is not easy to break but simple change in ph cannot break this bond simple change little bit change in the temperature of the medium cannot break this point you know simple environmental changes cannot break the bonds which are really strong bond someone very nasty has to work to break this bond is that right you know who is that nasty you know many nasty people but i want to know that who knows that nasty person or that nasty enzyme which can break down such a strong bond don't tell me the sister of the husband okay phosphodiesterase and it is breaking down a nucleic acid look here if an enzyme come and break down here this is a nucleic acid dna is a nucleic acid rna is a nucleic acid so if an enzyme come and break down here it has to be very very bad enzyme let let me show you that on them yeah this enzyme can cut here right it can break down the nucleic acid so this enzyme is called nucleus so these are the nucleuses which can break down the phosphodiester bonds right write down not simple ph changes not simple slight temperature changes these are the nucleuses of course a nucleus which break down the dna is called dnases nucleuses which break down the dna are called dnases and some nucleuses break down the rna bond so they should be called rnases excellent they should be called rnases now you know what a dna is then what are rnases these are basically nucleases and what are nucleus is the web very powerful enzymes which can break down the backbone of dna then again there are two types of nucleuses some nucleuses can only break the bond of the nucleotides which are present at the end either they will cut from here or they will cut from here but some are very very naughty they can even break down the bond from the center let me tell you if dna we have a long chain of dna i think it's a bit everyone can suffer something including the nucleotides right of course there should be nitrogenous bases also there's a dna molecule some nucleuses can attack only at the ends terminal ends they remove one nucleotide then again they remove another nucleotide then they may remove one more nucleotide so they attack at the end and start removing one by one piece they are less naughty these are called exonucleases what are these called exo nucleases so exonucleases primarily attack the ends of the nucleic acid chain right but those very naughty ones right which can attack even in the center right they can break down the center even they are called endonucleases endo nucleuses you must be having some friends which are exonucleases from your group they can remove one by one and some are very dangerous to split the group into two and do nucleases is that right in our assemblies it happens in our national assemblies i don't know you are talking about which country i think you are from ethopia okay let's come back we are talking about medical sciences not ethiopia right so what we are talking about that number one dna is the polymer of nucleotides when dna chain is made nucleotides are fused together this fusion process requires energy so incoming nucleotide bring extra energy and this energy is released as pyrophosphates are detached and energy is utilized to link one nucleotide with the next one and the bond which is made is very strong of course very strong what is the name of the strong phosphor diastole bond and to break down this bond the group of enzymes are nucleuses and if nucleases break down the dna then they are dnases and if some nucleuses attack the rna backbone to break down the phosphodiesters then it is rnases some nucleuses break down from the center from within yes these are called endonucleases why you don't talk loudly and if nucleuses break down nucleotides from the ends one by one these are axon nucleuses is that right you know them as you know your friends some are endonucleases others are exonucleases but some are very good they are polymerases they bring new friends and add to your group these are polymerases but they're very clever they only accept the new friends with this is going on even at the molecular level so don't be upset if practical life is going like that fine now once we have made this dna strand right this dna strand which we have made it can be written in many ways you know there's adenine adenine govanin cytosine yes thymine again adenine and govanin right now all of this dna strand it will always have one five and free and other three and fray it means of course on one side there's head end and other side there is not tail end foot hand please who has tail here foot and right so head end is five end and foot end is three and so not only nucleotide a single nucleotide has head and foot end even the whole chain has head and foot end so whole chain can be presented like this yes okay and what is this end 3n so every dna chain has one phosphate and phosphate containing end free end and other hydroxyl containing right phosphate containing is 5 and and hydroxyl containing is trey and so we can say that this chain is having special polarization it has two poles five pole and five and four and three three and four am i clear yes sir now sometimes why you are laughing it helps you to okay now you are comfortable now you want some hair here i don't know how to draw here because i lost them many years back okay now this is five and the three end right now actually look single strand is nothing in the life all of you at least most of you keep on looking for the other strand same is true about the dna these things are very much ingrained hardwired in our molecules even now this molecule does not want to live alone it wants another molecule there is a right so that it should become double stranded is that right dr that this single strand should not exist alone commonly it loves to have another strand now let's suppose how it arranges another strain okay of course some enzymes should come and help some enzymes should come and they should help to make another strand here but this is very very funny thing that if you want to make another strand for it should the strand be identical no it should not be identical identical things usually don't attract except in certain circumstances right adenine always fuses with what yes look let me tell you one thing there's a basic principle this is adenine right very happy it will always make bond with i mean but in a very unusual fashion please don't think it's something nasty yes there are many relationships which are really stable are like this right and but when you have a relationship like this that five end of one and free end of other right do you think they will have a strong bond with each other or weak of course weak no one likes to remain in this position for a long time isn't it so there are weak bonds here these weak bonds in between them are called hydrogen bonds is that right these weak bonds are called hydrogen bond actually adenine always couples with thymine and if you talk about guanine go and in so it always coupled with cytosine but again you know it is also happy actually you know why it is happy things it is upside down yes it depends on how you perceive the thing same is here go on in is very happy but you will be surprised even cytosine is very happy because it thinks that it is right and other side is upside down which are going in and cytosine you know they are happier couple they are happier couple so they have three hydrogen bonds right they are less happy so they have to connect two hydrogen bonds so adenine and thiamine have two hydrogen bonds governing and cytosine have three hydrogen bonds so which one is stronger bond governing cytosine and weaker bond adenine and thymine but on the whole did you invest lot of energy to put them together no so these are overall these bonds are weaker bonds or stronger bonds weaker bonds these are stronger bonds these are weaker bonds this is like a full family chain is that right now when adenine few couples the thymine we say these are these two nitrogenous bases are complementary to each other they are not identical they complement with each other in the same way these two nitrogenous bases also complementary to each other right now let's suppose now it needs the other strand and enzymes start working how the enzyme will work there's a funny thing enzyme which polymerize attention please let's suppose am the enzyme i'm going to make a new polymer for this strand another polymer here most of the enzyme which make the polymers of nucleotide they read the nucleotide chain from three to five end this is very important principle the enzyme of course look if i have to make a copy complementary copy you have to read the strand and then make a copy here complementary copy i should bring in front of guanine yes cytosine in front of adenine thymine but i will not start making chain from this end i will start making chain from this end four time you should start from the foot end right now so enzyme will start from the front end right and it will read from the three end right but it will polymerize in this fashion enzyme will okay i will make this which color you want now look here this is very sad situation and governing should be coupled with yes please cytosine and then there should be another nucleotide brought here and what should be here thiamin and of course what should be the relationship here phosphodiester bond and what should be the relationships here hydrogen triple and double right now we'll come to it is something like a nucleotide which is trying to run away from this business now this is thymine what should be here adenine and what should be the bond here phosphodiester now so and so forth right another chain will be made and this change yes please guanine and here it should be cytosine and here it should be thymine and here it should be right and of course which bond here please phosphodiester yes hydrogen bonds in between double triple triple hydrogen bond yes triple hydrogen bond double hydrogen bond double hydrogen bond now we can see with one strand we have one more strand right as far as nitrogenous bases are concerned if adenine are always with thymine and if cytosines are always with guanine if in this chain formation this principle is observed that governing is always with cytosine and adenine is always with thymine then we call that these two chains have nitrogenous bases which are complementary to each other so we have seen that we have made complementary to each other is that clear but there is one thing it is the five end of it and it is the three end but on this side is it the same no here is the three end and here is the five end it means relationship is somewhat like this yes geophoton right what do you think these two strands even though as far as nitrogenous bases are concerned these are complementary as far as nitrogenous bases are concerned these are complementary but if you look at their backbone are they parallel or not they're parallel look if i have two markers these are the heads of these two markers if these markers are like this these are the parallel are they like this no they are like this when two chains are like this they are anti-parallel they are anti-parallel so we can say that five end of one has three end of the other and three end of one has five end of the other so we can say both strands even though as far as nitrogenous bases are concerned they are complementary with each other but as far as their phosphate sugar back bones are concerned these molecules are anti-parallel to each other these are anti parallel to each other a bit of the terminology now congratulations you have made the dna molecule it was too simple to make right you just took nitrogenous bases fused them with the sides of sugars and what you made nuclear sides and you tie up the nucleosides with phosphate you end up with nucleotides the nucleotides put together are making nucleic acid right when they are put together what are these bonds in between phosphodiester bond strong bond weak bond so need to be they can be broken with little temperature change no can they be broken with little ph change no we need special enzymes to break them these enzymes are nucleuses if nucleases break from the end then these are axon nucleuses if the breakdown from within and the nucleus then i said nature very few things are alone right this trend should have one more strength one more strand and if one strand is five to three then other strand is going to have its three end with the five of the first one and second strand should have five end with the three end of the first one when this situation is seen we say as far as nitrogenous bases are concerned if every guanine is with cytosine and if every adenine is thymine we say as far as nitrogenous bases are concerned these two strands are complementary to each other but when we look at their backbones right five end fuses with the three end and three and fuses with the five end this type of arrangement is called anti parallel so today onward you will remember whenever there is double-stranded dna molecule whenever there is double-stranded dna molecule if it is a normal molecule then nitrogen as far as nitrogenous bases are concerned both molecules double both strands should be complementary but as far as backbones are concerned they are oriented anti parallel is there any question here there's no question now one more thing that is that these are not only simple strand then these are twisted then these are twisted for example [Music] if this is one dna strand right other dns strand is twisted around it like this and of course it's very easy to understand if this is the five end of the one what should be the other three end and and and and you see let me follow it it is the three end of this one what should be the five end is it clear and these are what present in between nitrogenous bases these are complementary to each other and they're held together by hydrogen bonds and backbones are made of phosphate and sugars and they are held together by phosphodiester bonds right yes it should have its three and here and it should have five and here now this is double-stranded dna molecule in this double-stranded dna molecule you can see that some minor if you move your finger on curves of this i'm talking about the curves of dna when you move your finger on the curves of the dna what you feel there's a minor groove there's a very big groove then there's a minor groove then there's a major groove so flanks of these molecules are grooved and repeat repeatedly there are minor and so man what you think about these groups do they have any importance as far as dna is concerned yes they do have right i will tell you right now but before that i want to tell you that the minor groups and major groups for example this is minor group this is minor group here is minor group here is minor group yes this is major group major group major group and major group that's the importance of this these groups determine what type of different factors will bind with dna and regulate the expression of genes number one number two there are some drugs which are related with it this is the drug very interesting type of drug which can sit only in the minor group let me draw the drug like this this drug look like a i hope you have seen at least one duck like this right it's like a duck actually there's some drugs which are like duck molecule these ducts get intercalated interrelated at this point is duct set over fit into minor group a major group minor group and when these ducks sit into minor groups yes this is a group of drugs right they are just like ducks right and they disturb the minor grooves and if minor groups are disturbed attention plays if you want to replicate the dna you have to open up the dna if you have to replicate the dna then you have to open up the dna is that right now if this duct is there and holding this minor groove can you open up no no normally what happen when a cell is going to divide when a cell is going to divide what really happens that is dna both strands will go apart and every strand will make a new copy is that right now if we have given this drug it fits into minor groove can enzymes which are going to copy the dna can run down comfortably no suppose this is the enzyme which polymerizes the new dna molecule it runs in between here it will fall out you can see it it is crying yeah the tears why because the ducts are there and the mineral group and these ducts don't allow the polymerases to run it can cell replicators dna no cancel proliferate then no no this drug is ductinomycin this drug is yes please dectino myosin so ductinomycin molecules basically intercalate into minor grooves ductinomycin molecules basically interpolate into minor groups and then they interfere with replication and transcription of dna and if they don't allow the dna to make more dna or they don't allow the dna to make more rna so replication and transcription is disturbed this drug is used as anti-cancer drug this drug is used as anti-cancer drugs now you know how dictanomycin work let's have a break and then we'll continue again

Channel: Dr. Najeeb Lectures

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Keywords: dna structure and function, dna, structure of dna, dna structure, biology, nucleotide, deoxyribonucleic acid, genetics, double helix, thymine, adenine, cytosine, genes, dna structure model, what is dna, phosphate, phosphate group, function of dna, nucleotides, ap biology, bases of dna, four bases of dna, components of dna, science, parts of a nucleotide, dna function, dr najeeb, ninja nerd lectures, guanine, nucleic acid, dna bases, rna, ancestry dna, dna test, forensics, dna sequencing

Id: -1Zj4SdhLSM

Length: 61min 5sec (3665 seconds)

Published: Sun Apr 18 2021