Heredity and evolution class 10 lecture 3 | 10th science 2 chapter 1 Maharashtra board

Added: 2026-05-30

[00:00:00]Hello student welcome to Nshala. We provide quality education free of cost.

[00:00:06]No paid badges, no membership only free educations to everyone. Children in previous lecture we started heridity and evolution chapter of class 10. In that chapter three important concept we completed one heredity second central doma and third transcription. And in today's session we are discussing about the translation transllocation and how mutation takes place in DNA. Let us start today's session. Children in previous lecture we completed concept of transcription. In that we understood that whatever information present in DNA that information is copied on RNA.

[00:00:47]Especially we talked about mRNA.

[00:00:50]So synthesis of mRNA as per the nucleotide sequence of DNA is called transcription. In earlier lecture we discussed this. So what was the end product of transcription? End product of transcription is mRNA there. So this is your mRNA there. Once mRNA ready this mRNA will come outside in this way. So this mRNA where formed where it is produced? It is produced in the nucleus.

[00:01:19]First question. Second, once the mRNA ready where it comes, it comes in outside area called as a cytoplasm. So second important thing once the mRNA ready it will move outside the nucleus and comes in that area called as cytoplasm.

[00:01:40]In cytoplasm one special structure present called as a ribosome.

[00:01:45]Now this mRNA will come to ribosome.

[00:01:49]Why ribosome? Why? Because ribosome is a protein factory. The whatever protein needed in body this all protein ribosome is making.

[00:02:01]So if you remember the central doma concept we want protein and this protein information was there in DNA.

[00:02:11]So information from DNA it is given to mRNA. mRNA will come to ribosome.

[00:02:18]Ribosome will make protein.

[00:02:21]Are you getting? So children you see we are telling mRNA mRNA M for M for mango.

[00:02:28]No M for messenger because this mRNA brings the message from DNA to ribosome.

[00:02:35]Therefore it is called messenger RNA.

[00:02:37]No, it brings the message not. So concern understand when mRNA move outside the nucleus it bring the message for amino acids. So this message is in the form of coded there. It is a coded message there. So this coded message from DNA comes to ribosome with the help of our mRNA.

[00:03:01]So what is the role of mRNA? To carry message from DNA to ribosome.

[00:03:08]So message for what? message for amino acids. Now what is amino acids? Let's understand that. Now see children here in starting lecture we discussed that curly hair is one biological character there. Hair what there is one type of protein there. Hair is one type of protein there.

[00:03:28]If I want to make hair means I'm making protein that simple hair I'm making means I'm actually making protein. These are protein there. But sir this protein is made up of anything or yes this protein is made up of small small units called as the amino acids.

[00:03:50]So this is my first amino acid there there is second there third there like that many amino acids joining then I will get the protein.

[00:04:00]So protein is a chain of amino acid.

[00:04:05]So about this information mrna will bring but s why there is need of mRNA message why you want if you want to make protein message what why there is a message word is used see message means specific information there no message means it's not random anything there specific information there for example see the first amino acid which there here glycine there second one what there I see u Third valind there, fourth cy again here glutam like that in each protein amino acids are present in a specific sequence like your school role number in your school role numbers are there. Everyone is having 1 2 3 like that role numbers there. If I'm saying role number 20 then a particular boy or girl only will stand not everyone.

[00:05:00]So role number gives information to you.

[00:05:03]So role number is your code there of school like that mRNA brings code for these amino acids.

[00:05:12]So as per the code first amino acid, second amino acid, third amino acid is decided. Therefore we are telling mRNA bringing coded message. Coded message for whom? Coded message for these amino acids. And these amino acids when they will join join join then finally we will get the protein protein forms then we will make the hair. If mRNA not bringing message then amino acid will not come amino acid not there then protein not there protein not there then hair not there hair not there then football there getting so important there mrna should bring the message okay sir that message which mrna bringing what message there in that like this we find a u g c a u u g gu like that message there now these message which mrn is bringing this message for amino acids. One amino acid consists three nucleotide. If you see here a u g a u g this gives information about one amino acid that is methionine you don't think about that names no name is just for your information thereine isolucine amino acids that's it. So a UG gives information about one amino acid with your end. Then C c A will give information about second amino acid that is proline there. U G will give information about third amino acid lucinder.

[00:06:49]So if you see here the one amino acid is decided by three letters A U G together decides methionine. It's not that A for U, A one, U for second amino acid, C G for third amino acid. All three letters together, these letters we call as a nucleotide. How many nucleotides together? There three. So the code for each amino acid code for this amino acid consist how many nucleotides together? 1 2 3.

[00:07:25]So code for each amino acid consist three nucleotide.

[00:07:31]Therefore it is called as a triplet codon. Tripate why triple 3 a u g3 that means you understand you getting. So code for what? Code for amino acid. So code for each amino acid consist how many nucleotide? three nucleotides serves. So that only we called as a triplet codon. How to define simple code for each amino acid consist three nucleotide.

[00:08:06]Code for each amino acid consist three nucleotide together called as triplet codon. If suppose I'm telling you in this mRNA how many codons are there?

[00:08:18]Codons how many? Check. A U G one codon there. C A second codon there. U G third G C U fourth. A GC fifth. Five codon. Five amino acids will form.

[00:08:38]Clear? So mRNA brings the coded message.

[00:08:43]mRNA brings coded message for amino acids.

[00:08:47]And the code for each amino acid consist of group of three nucleotide.

[00:08:53]Code for each amino acid consist of group of three nucleotide. And this group of three nucleotide we call as triplet codon. How many triplet codons?

[00:09:03]That number of amino acids will be added. For example, in this diagram 1 2 3 4 5 codon five amino acids will be added in a chain here. There sir only five there. No there are about 20 essential amino acids are there. Means in my body how many proteins are there?

[00:09:26]That all proteins mainly made up of 20 type of amino acids that 20 amino acids are having their particular code. For example u uu phenile alenine cu leucine like that many others.

[00:09:44]We have to learn this. No, just I'm showing you what you have to learn. How many essential amino acids are there?

[00:09:53]20. By using that 20 amino acids, your all proteins are formed. But remember that everyone is having their code. So any amino acids if you see everyone serene amino acid then it is having one code like that.

[00:10:09]So many codes so many aminosides who studied this one famous scientist there Dr. Harumin the corana Indian origin scientists there did research outside the country their main role their main contribution there to find out this just now I shown to you this means for particular amino acid which code will come for next amino acid which code will come this all study did by Dr. Haru in the Quran name you have to learn. Second what is their contribution? Contribution what there contribution there in discovery of triplet codon for how many amino acids? 20 just now we discussed for that they got Nobel prize in 1968 that your pit work there. Now children mRNA when it comes outside no this mRNA I shown only five amino sequence five codon I shown no just now but only five there but no thousands of codons are there 1 2 3 4 dot dot dot dot many are there like this thousand there you go that side to count I'm showing this much okay so each ma is made up of thousands of codon sir if thousands of codon there then amino acids will be 1,000 1 th00and amino acids will be J obviously because one code one amino acid if codons are thousand and then the amino acids also will be th00and we know yes or no so codon how many that much number of amino acids will be there so long amino acids will join to make that protein now sir this mRNA is having codon according to that amino acids will come but Who will bring that amino acid here? That is also important there. For that we are taking help of tRNA. tRNA stands for transfer RNA.

[00:12:09]So as per mRNA information when we are making a protein we need amino acids.

[00:12:17]Why sir? Just now we discussed no protein. What are there? Protein is a chain of amino acid. Amino acid coming then only I can make protein.

[00:12:27]So this amino acids to make that protein these players will bring who are this 1 2 3 these all are tRNA there. So tRNA what they bringing see on their head amino acid there wait no huh this amino acid there here also amino acid there here also amino acid so tRNA what doing tRNA transfer no sir amino acids so tRNA transfer amino acid tRNA transfer amino acid to ribosome to make that protein s now suppose Here on mRNA we are having a UG.

[00:13:11]Then sir this we understood that tRNA will bring the amino acid but a UG it will code for something amino acid. No then here 1 2 3 there which is a correct one or anyone allowed there. No anyone it is not allowed. You recall the cle cell anemia in cle cell anemia nice concept there.

[00:13:34]If one amino acid wrong happening no you will lifetime you will suffer from cle cell anemia. You remember that no cle cell was there your RBC shape will become sickle like this shape happening.

[00:13:46]Why? At sixth position like this there 1 2 3 4 5th sixth suppose here sixth there at sixth position. Sixth position glutamic acid this amino acid needed. By mistake there instead of glutamic acid valid comes see here one only change happen all amino acid sequence has it is exactly same there natural normal there one only mistake happen what is that one mistake that instead of sixth position glutamic acid valin comes one amino acid change one lifetime disease you will get in gift no treatment No cure lifetime I'm telling sickle cell anemia only normal treatment you can give but from body you permanently can't remove that disease so so danger lifetime this is I can get due to one mistake so like that any amino acid I'm adding so you add here one you add here like this then protein will form but it will be abnormal a protein abnormal you will be abnormal so here correct amino acid adding is veryant important and that correct amino acids to add we are having one system getting what is that system please see here tRNA when bringing amino acid no tRNA also having one sequence if you see here U A it is called antic-codon it is called antic-codon where antic-codon present antic-codon is present on tRNA okay sir tRNA is having antic-codon So this what better this we called as codon this is codon there codon a u g is a codon sir confusion not happening then codon anticcodon who is coming first and mrna is coming first in this picture okay then mrna is having codon codon front who is leaving that is anti antic-codon so it's front which there that is your antic-codon simple anti antic-codon right so codon is present on mRNA antic-codon is present on tRNA fix here codon on mRNA antic-codon on tn easy okay there why this antic-codon made here if you see this antic-codon pairing is very important there if you remember the base base pairing rule last lecture we discussed Because A is always A is always paired with A is always paired with U.

[00:16:34]G is always paired with C. A with U, G with C. This is called complimentary base parallel. Check here. Upside U there. So A is A is pairing with U. So here U there then downside exactly you'll find A there. Check.

[00:16:55]Right. Now upside A there then A front who is there U see here you will find the U there G pair with C or C pair with G C there then downside C G there so according to base pair complmentary there compliment lock and key type lock and key there no key is specific for lock there or anyone's key we can open the lock not like that so anti-codon could complement If here matching happening if it match then only amnesty will be accepted and understand the concept and a learning afterwards learning learning after understanding there no it is pit we are doing concept understand we are teaching no you understand the concept don't be why running behind that learning out of slowly concept understand Everything mass automatic will come. You just first listen carefully concept concept understood then learning feeling coming that nice feeling that uh concept knowing learning also.

[00:18:10]So tRNA bringing tRNA bringing tRNA will bring amino acid correct amino acid K1.

[00:18:18]Now how to check matching? A U G codon C A U A C antic-codon match. Perfect. Add amino acid getting so tRNA is having antic-codon. tRNA is having this antic-codon complmentary to codon of mRNA.

[00:18:40]I'll repeat tRNA tRNA is having antic-codon complimentary complimentary means opposite opposite to what codon of mRNA so like this can you tell me in in this picture suppose I'm asking to you ca I give here number codon number 1 2 3 4 5 you have to tell that ca this is one antic-codon there this tRNA will match with which codon of mRNA. Check complimentary rule. Remember just now I gave what is the rule? Complimentary rule. A always pair with U and G always pair with C. Complimentary you have to check. See here C there G there A there.

[00:19:31]So C compliment G sir.

[00:19:35]G sir means G C G. Huh? G there sir. C A U G C U search here where GCU there see G C U means this tRNA will come here and joins clear second now this is a one tRNA there having anticipod u A can you tell what is what will be the complimentary to U there then A sir A there then You see that G A U G where present A U G A U G here there a U G means this will go to first codon G CU GCU it will go to it will go to second okay now here I'm having one tRNA with the anti-coder a AU a AU You will tell this a a U will go to which codon? 1 2 3 4 1 and 2 already 3 4 5 You will comment to which codon this antic-codon will fit. Use this rule base pairing rule. Okay. Tear any confusion.

[00:20:57]What to remember here? Translation we are talking about. What is translation sir? MRNA bringing coded message for amino acid.

[00:21:06]mRNA bringing coded message. So this coded message which mRNA is bringing this coded message is having number of codons. Thousands of codons are present on mRNA.

[00:21:19]So thousands of codon is present on mRNA.

[00:21:23]According to that tRNA will bring amino acids. Amino acid amino acid amino acid who is bringing all tRNA will bring. But sir correct how correct I'm how to find easy just now we discussed that each tRNA is having antic-codon each tRNA is having antic-codon complmentary to codon of mRNA each tRNA is having antic-codon complmentary to codon of mRNA so as this matching then your amino will come this is only translation read here tRNA bringing what it is bringing amino acid for that tRNA what is there tRNA is having antic-codon tRNA is having antic-codon complimentary to whom sir complmentary to the codon of mRNA in this way 111 amino acids is added this whole process we call as a translation you understand why it is called translation see now here this is one language there. A U G G C U U like that one language there. Then suddenly it will give information about amino acids.

[00:22:37]Then amino acids also one language know is glutamic acid val suddenly language changes. Aug this language goes am I language starts change in language is called translation. From primary we are learning this language changing then it is called translation. Therefore they use this word translation.

[00:23:00]Okay. But remember sir mRNA is having thousands of codon. As per the codon as per the codon of mRNA tRNA will bring the amino acids.

[00:23:15]as per the codon of mRNA tRNA bringing amino acids but how correctly added for this purpose tRNA is having antic-codon we going huh for this purpose tRNA is having antic-codon complmentary to codon of mRNA for this purpose this tRNA is having antic-codon complmentary to codon of mRNA this whole process we call as translation.

[00:23:48]So once your translation completes here, translation completes here then 11 one and 11 one amino acids will come continuously. Now suppose this is your first amino acid came with this tRNA.

[00:24:02]This pink is a second amino acid comes with second tRNA. Then this amino acid also we have to join. No. Why to join sir? At joining then only chain will form. No because amino acid chain is protein there. So many amino acid first amino acid second amino acid third amino acid fourth fifth like that thousands are there we have to join.

[00:24:26]So if you want to join then something bond needed this bond we called as a peptide bond. Remember amino acids are joined together joined together by peptide bond. Observe this peptide one who will make for this purpose inside this ribosome this background blue pillar looking to you this is ribosome there for that inside this we are having one special RNA called as rna rn R means ribosomal this RNA is present in the ribosome therefore it is called as RNA knowing no in n standard only you completed this concept huh Again assume that RNA is a ribosomal RNA present in the ribosome.

[00:25:18]What is role of that? It will join many amino acid. It will join. By which bond?

[00:25:26]Peptide bond.

[00:25:28]Okay. There many amino acids are bonded together joined together by special bond called as a peptide bond. And that peptide bond who will make it will made by sir RNA ribosomal RNA. Okay sir till here we understood.

[00:25:47]Understood. No now tell this first question. What is function of mRNA in protein synthesis? mRNA knowing tell whether mRNA stores amino acids whether it brings the coded message from DNA. It breaks the peptide bond or it produces the ribosome.

[00:26:09]What will be the answer?

[00:26:12]Easy then no huh ch. So from DNA to ribosome mRNA is bringing message. So in in the function of mRNA we have to write it brings it brings the coded message from DNA DNA to ribosome. MRNA will bring the message.

[00:26:34]Second the code for one amino acid on mRNA code for this. So the code for one amino acid on mRNA know a UG together code there. This is one code there. This is second code there. What you call this code? Anticcodon gene triplet codon or chromosome.

[00:26:53]What sir? Easy there sir. 1 2 3 it is a triplet codon.

[00:26:59]Okay. Okay sir. No problem. So next the complimentary sequence present on tRNA this is your mRNA there on mRNA just now we discussed on mRNA what else mRNA is having codon mRNA they are not asking they're asking for tRNA complimentary sequence present on tRNA to this complimentary what this U A is codon no antic-codon yes it Anticon peptide what? Peptide bond is bond between two amino acid.

[00:27:40]That is amino acids are joined together with the help of which bond? First amino acid, second amino acid joined by one bond. Second, third joined by another bond. What is this bond? James bond.

[00:27:52]What is name of this bond? Check.

[00:27:54]Hydrogen bond. No sir. Glycositic bond?

[00:27:57]No sir. Peptide bond. Yes sir. It's a peptide bond there. So amino acids are joined together with the help of peptide bond. Joined together by peptide bond which is made by RNA.

[00:28:11]Okay sir. Now see here once one one amino acids will come one one first amino acid came then second this amino acids are joined together to make a protein right there. And this whole process where happening it is happening in the ribosome. Please say now suppose here one amino acid came one tRNA comes here tRNA comes then it will add one amino acid once the ribosome read this a U then ribosome will move to next see here a U then next codon what G so you you see now ribosome here in this area it is reading a UG so once the ribosome read first codon at a Same like your textbook first page reading then you'll go for second page.

[00:29:01]No huh no same. So a U G reading over then ribosome will move to next cod G then G also G G also reading over then ribosome will move third it will go 1 2 3 same only there only I'm showing position of ribosome or don't think that three different there same only there first ribosome we are there G G C G like that it will go on so who is moving There mRNA no ma same there same position there ribosome move. So ribosome move from one end of mRNA to another end. Yes or no? First ribosome was at this end then it started to move like that goes to that end. Simple ribosome move from one end of mRNA to another end of mRNA by distance of one triplet codon one triplet codon only it will move it is not moving that half like this then suddenly goes here pattern there is that like this doing any on ground running our mRNA it is on MR systematic needed no everything so ribosome move from one end of mRNA to another end of mRNA. How? By how much distance it will move? It will move by distance of one triplet to so ribosome was here. Now here, now here location changing. No, location changing.

[00:30:43]Therefore, it is called as this process is called as transllocation.

[00:30:48]What is word they using? They are using the word transllocation.

[00:30:54]Trans means to change location changing.

[00:30:57]Get? So what is transllocation?

[00:31:00]Ribosome keeps moving from one end to another end of mRNA.

[00:31:07]Ribosome keeps moving from one end to another end of mRNA by distance of one triplet codon. First this codon then move to next codon then move to next codon like that. So ribosome keeps moving from one end to another end of mRNA by distance of one triplet codon one time one triplet codon it will move this is called as transllocation.

[00:31:37]Now once all amino acids are added like this amino acids added one chain will form. Now this chain one more chain will join again their structure will change and finally we are getting a complex protein. How complex protein will form?

[00:31:58]Many amino acid chain together make a complex protein single layer and simple many together complex easy. So in this way you complete the complex protein synthesis. So in this whole process what there first transcription information from DNA copied to RNA.

[00:32:22]Second translation according to mRNA ribosome will add add the amino acids with the help of tRNA. Then protein will form many proteins will come together to make a complex protein. Clear children one last concept you have to understand about the mutation.

[00:32:43]Just now we discussed about cle cell anemia. How there it is? Suppose I'm having one sequence here.

[00:32:51]Now suddenly if this sequence change, sequence change means what? For example, see here it is there CTG there. Can you see this CTG there? If this CTG becomes GG CTG sequence there instead of that it becomes G G.

[00:33:11]So this change in nucleotide know first which nucleotides were there C t G now which they became G G sudden change in nucleotide like this this change can be anyhow means this can be deleted only this this area can be delete then again it will join something new will be added in this in this sequence something new will be added Are you getting change there? No, the change can be in any way. New nucleotides can be added, old one can be deleted, old one is replaced by another one. Anything possible. So any sudden change in the nucleotide, any sudden change in nucleotide. For example, see here G A T there. So originally it was D GC. So sorry TGC. So this T g is removed in that place G H TK there's also change there. So that only I'm telling new will be added old one will be deleted one is replaced by another something change will happen in the sequence. So such sudden change in the nucleotide sequence creates problem to you. Problem sometimes very minor there. Minor means minor means simple there. For example, if something change happen like that you'll find say some childrens are having extra finger one extra. Are you getting instead of five they're having six mutation there it is minor change there.

[00:34:46]Some are having very considerable change also possible. Conceivable means lifetime pain will be there. Just now we discussed cle cell anemia, color blindness that in 1971 it was there no albvinism. Alvinism where hair becomes white, skin becomes pale, eyes pink.

[00:35:06]Recall that all diseases possibility there because of mutation.

[00:35:12]Are you getting? So mutation word there sudden change in nucleotide which can cause minor or considerable change. So how to define it? Any sudden change that occurs in nucleotide sequence here like this TG C instead of that G A TM this is changed there. So any sudden change in the nucleotide sequence of gene what will happen because of that it can cause minor minor means small change that six finger or considerable change considerable change means cle cell anemia color blindness albinism like that lifetime something disase you will get. So this process is called as mutation. What is mutation? Any sudden change in the nucleotide sequence of gene. Any sudden change in nucleotide sequence of gene which causes minor or a considerable change in character.

[00:36:13]Minor misunderstood minor means small change something will happen in your body or something major will happen that lifetime you will suffer because of mutation. So mutation is not good. One two examples then of mutation. One cle cell anemia we just discussed if your RBC normal rate is by concave there by concave by concave means like this shape will be there okay RBC normal RBC if mutation happen then your RBC will change the shape like this understanding or no like this to cut the grass so like that you will see the shape of RBC this is normal RBC there it is cell there okay why happen This genes nucleotide sequence changed. Get it? So mutation can leads to minor changes also like this dangerous considerable change also possible.

[00:37:07]Is it clear? So if they ask you what is mutation? Generally they will ask objective type of question on this. What is mutation? Any sudden change in the nucleotide sequence. any sudden change in the nucleotide sequence which causes minor or considerable change in the character. Now 2 minutes here focus in March 20 board question I'm talking now pyq there it is March 20 they ask one question to you transfer of information from a molecule of DNA to mRNA what it is called what is the answer for this information from DNA transfer to RNA mRNA what it is called whether it is called transcription translation transllocation or mutation DNA to RNA obviously it is transcription here second now this question asked in March 24 24 question there in March paper minor changes occurs due to change in position of any nucleotide is just now we discussed minor or considerable change because of what because of transcription no sir transllocation No sir. Mutation.

[00:38:28]Yes sir. Mutation will be the answer for this. Okay. Now next one see. Now this question they asked in March 25. What is the question? Any nucleotide change?

[00:38:40]Any nucleotide of gene suddenly changes then minor changes occurs in that person because of what? Because of what?

[00:38:48]Because of transllocation, disability, mutation or changes. You will answer this. You will comment in the comment box A B C D. What will be the correct answer for this March 25 question?

[00:39:02]Clear? I think up till now whatever concept you completed, you understood it properly. If you like our videos, please subscribe the channel and share the link with your friends.

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