2026 memo life sciences paper 2 grade 12 may june exams 2026 life sciences paper 2 grade 12 june

追加: 2026-06-02

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[00:01:22]>> Duke, we focus on quality. [music] >> Welcome back to our class. Today we're going to be talking about life science paper 2 junior exam 2026 and we see the proposed memorandum.

[00:01:36]According to our prediction, we see that we did predict 99% correct. Uh in the our previous uh uh video which we discussed about uh we see that uh all the questions we talked about they are here. They here only 1% which is a little bit diverging from what we talked about. The first question which we discussed that time said that the father of genetics is we say this priest called G meno and then you get your two marks. This is a guy who uh did a very great job in genetics. Uh they're saying that during which phase of cell cycle does DNA replication takes place?

[00:02:18]DNA replication takes place during interphase. We said about it. Then they saying that the cell has 24 chromosomes at the beginning and then how many chromatids will there be in daughter cell at the end of pro uh tphase one. So we see that at meiosis we have 24 chromosomes meaning that these are 12 pairs. Yes, there are 12 pairs. But these 24 chromosomes after dividing after dividing each cell is going to have 12 is going to have 12. But this one is not pairs. But don't forget that each chromosome is made up of two chromatid. This chromatid and this chromatid is made up of what? How many chromatids? Two chromatids. So if I have 12 chromosomes, how many chromatids will there be? 12 * 2. So it's going to give me 24. So the most correct answer here is going to be 24.

[00:03:11]Which one of the following refers to the end product of mitosis of human somatic cell? Of human somatic cell. Remember a somatic cell is a cell. Which one of the following refers to the end product? The end product of mitosis of a human somatic cell. So remember human somatic cell um is supposed to have the same number of chromosomes. Supposed to have the what? The same number of chromosomes. What changes in there is the uh the how many chromosomes if started with the 24 it will end up with 24. You understand? But those 24 what are they going to be? Are they going to be the same? Uh yes.

[00:04:00]Remember that uh in in in in humans uh the cells are um they start as deployed to n and then they end as deployed and the number of chromosome if you start with 24 you end up with 24. So it means that our correct answer our most correct answer is going to be the they they end up uh two deployed uh daughter cells.

[00:04:25]Which one of the following is a characteristic of bipedalism? Which one of the following is the characteristics?

[00:04:31]Remember by pedalism you have to talk about the position of forman magnum is in a more forward position. Here they're talking about backward out. The the spine is S shaped. Here they're talking C- shaped out. The pelvis is short and wider. Short and wider not long and narrow. So the answer becomes B. So B becomes the most correct answer. They're saying that below is the list of reproductive isolation mechanism. The reproductive isolation what mechanism. So what are they saying? Species specific courtship behavior prevention of fertilization uh pre adaptation of different pin uh uh pollinators. All right. Which one of the following is a combination referred to as a reproductive isolation mechanism in plants? All of them are reproductive isolation mechanism but what applies to to plants. So the first one is prevention of fertilization and then the second one is the adaptation to different pinators. Yeah, prevention of fertilization can result in uh polyploid uh triploid. Yeah, depending on so it might lead to failure of fertilization take place depending on which versus which. So it is two and three. Two and three. Two and three looks to be C to be the most correct answer. An investigation was done to determine the chance in antibiotic resistance in bacteria over a number of generation. The results are shown in the table below. Okay. How many times did the percentage of antibiotic resistant bacteria in the population increase between 50? They're looking for the percentage. Percentage from 50th.

[00:06:25]Where's 50th? Uh 50th. Okay. To 500.

[00:06:33]Okay. Where is 50s?

[00:06:35]We see that number of generation is here. They said increase uh increase in the between this to this 5,000 to 5,000. So in this case I have to calculate and I find out so it's going to be uh final minus initial over initial. What is our initial? Our initial they said in terms of percentage was five and final was 40.

[00:07:11]So I'm going to say 40 - 5 which out of 5 uh which gives me 35 out of 5 * 100 * 100 of which this 35 / 5 that is 6 6 35 oh did I say yeah 30 then times is 100. Okay, let me use a calculator and I see.

[00:07:46]Yeah, so it's basically is 35 / 5 is 7 uh 7 uh * this 100 * 100 which gives me 700.

[00:07:58]So the most correct answer becomes uh becomes D. D becomes the most correct answer. Stem cells are cells we say that stem cells these are cells which have not undergone differentiation. So they're able to divide and form other body structures and differentiary cells that are found umbilical code is an example of stem cell. So B looks to be the most correct answer. 1.8 uh 1.8 1.9 1.9 they're saying that in tomatoes uh the gene for fruit size uh and color are located in different chromosome. The gene for fruit size has two als and small G. The gene for fruit size also has two als and then the yellow. The diagram shows the al from one tomato plant. Okay. They're saying that which which correct genotype is representing this tomato. So we said that G means they said genotype. So it's going to be capital G small G and then it's going to be capital R capital R. So it's going to be capital G. Small G is this and also this. But now capital G means what? It means large and small R means yellow. So I'm going to have to look for large and is it large and yellow.

[00:09:24]Uh capital R. Capital R is red, not yellow. So going to have to look for large and red. Large and red, which looks to be this. So B looks to be B looks to be the most correct answer.

[00:09:41]The tomato plant is crossed with the plant that has small small small what?

[00:09:51]Small yellow fruit.

[00:09:54]Okay.

[00:09:56]What is the expected ratio of offspring in this genotype? we expect to have a ratio of uh 9 to 3 to 3:1 meaning that we expect to have three four different uh genotypes but in this case in this case uh let's cross and we find out they're saying that the tomato is crossed they're saying that this tomato is uh this tomato plant is crossed with the a tomato plant that has small yellow. So if this this tomato, which tomato is this? Okay. Meaning that I'm going to have G G is it G G small G small G capital R capital R and then it's going to cross with small and yellow. So it's going to be small small G small G small R small R. So what is the genotype? What is the expected uh phenotype uh in this kind of ratio? So in this case I have to find out what is it going to be. So in this case I have to find out. Let's find out if you go for the shortest way and then find out this G is going to go with this G. So capital G small G and then this R is going to go with one / this R capital R small R. Since all of them are capital R, small R, all of them are going to be like this. This and this they are the same. So all of them they going to have that. So the only difference is this versus this. So it means that another one is going to be small G, small G, capital R, small R. So meaning that all of them they're going to be like this in equal proportions because these are the only two which are different. But you if you don't understand this, you have to do a pin square and then you fill in all the information. So in this case since all of them are going to be like this and this so it means that the ratio is going to be 1 to 1 and then a makes it to be the most correct answer. Then we go to the next question who got 20 out of 20 and if you are writing did would you have got 20 out of 20? Let's go to the terminologies and we see how we can smash these terminologies. Division of the nucleus I talked about it and then I say that this is nucleus is called cario but division kinosis kiochinesis then they're saying that the structure that connect the two chromatids together we said central central the type of variation where characteristics f into distinct categories we said it is we talked about continuous variation.

[00:12:56]This is called this disc this continuous variation.

[00:13:02]Discontinuous variation present the distribution of species on different continents serves as evidence of evolution. We call it bio geography.

[00:13:16]by geography they're saying that they're saying that the bond that connects the two strands together of DNA we say that is called weak hydrogen bonds [clears throat] the area where two chromaties overlap during crossing over we said is called chasma chasma the type of inheritance where neither of the al is dominant and the hetererozygous offspring have an intermediate. The moment you see an intermediate, we said we call it incomplete incomplete dominancy.

[00:13:59]That's what we said. Mhm. The [clears throat] natural shape of DNA we said double helix. It's called double helix. They're saying the position of a gene on the chromosome we said is called locus. And we say that if there are lot we call it loai. So you guys you see that everything everything I hope you guys you are getting it the people who are revising with this paper. All right.

[00:14:26]We're saying that the future that cause the African ape to be prognandas. We said that the the the future is large jaws but the large jaws can only be accommodated the large teeth can only be accommodated by large jaws. Therefore the large teeth also makes if someone has large teeth you'll see that even the the the the what the jaws are protruding out. So large teeth also contribute on the prognanthism. All right. So the answer becomes a both a and both a and b characteristics that human share with other African eps. eyes in front long upper arms both A and B they're saying that the source of genetic variation in population random fertilization yes random mating is both A and B we talked about the source of variation H six marks we go the next question name the monomer we said the monomers of nucleic acids are called nucleio O tides the nor monomer. So this thing is a nucleotide.

[00:15:45]So you see even if I don't know what is it but the moment they said mon and they said this is a nucleic acid automatically I will say that this is a nucleotide.

[00:15:55]Yes. What is one is a phosphate phosphate group is a phosphate. Someone is going to ask me what about if I wrote phosphate. Correct. H what is T uh sorry three three is a nitrogenous a nitrogenous baseh they're saying that name the molecule number two if found in the following number two number two since is a sugar I will say that is de o ribos sugar sugar and then in RNA is ribos sugar.

[00:16:40]Name the molecule that is name the molecule that is name the molecule uh name the molecule that is found in DNA only that is thymine. Thymine and then name two organels in human cell where DNA is located. We say that human cell we have h the nucleus because we say the nucleus is found in the nucleus and then we say that is found in the mitochondri or mitochondria. Mitochondri cool but we say that these are organels where DNA is located in the nucleus. Then we got the next question. uh we said that the diagram below shows the evolution relationship between the same species the homminiz speciesh they're saying that step one identify the type of diagram represented uh in here we say that this diagram what did we say we say that is phogetic phogenetic tree we talked about this guys those people who don't have a distinction m book you know what you're supposed to do you just get a decent material book from the link in the description below.

[00:17:56]You'll be able to get all these answers.

[00:17:59]Yes. Name the homminide genus that is thought to be a common ancestor homminide. Common ancestor of uh oropathy.

[00:18:14]Uh meaning that the common ancestor of uh Yes.

[00:18:22]So the genus they they're talking about the genus. Yeah. So it means that based on this not the other side based on this so we see that it is osteropithecus name the homminid genus isolopus.

[00:18:43]Yes. Then they saying that um when in when in million years did the species which was thought to be the first used tools remember is homohabilis. When did it appear when did it appear?

[00:18:58]Homohabilis.

[00:19:00]Homohabilis we see that homohabilis appeared there.

[00:19:06]Uh if I you can draw it with your own it looks to be 2 million years ago. 2 million years ago. But if I I'm not using a ruler, you are supposed to use a ruler and then confirm it. But if you look what it looks to be 2.1. So uh maybe 2.1 million years ago. Million years million years ago. Yes. So maybe two maybe they will give you a range between 2 and 2.1 million years ago. So meaning that if you got give that give you a mark if you get that give you a mark but please make sure that you measure me I'm just estimating because I'm using a screen they're saying that which species is most recent common ancestor ofthecus uh gahi and homo habilis gahi is this and homohabilis.

[00:20:04]So they come back they come back it is oropithecus apharenis. So that is the oropithecus apherences. Name the species to which uh name the species uh that would have competed for the same resource with homo sapion species. If uh you look at that we shall see that same homo sapiion same homo sapiens homo sapiion homo sapiens are here I say that draw a line and then which touches so it shows that homo neandalencis so the answer here is homo neanderthalencis name hommonal is thought to be a transitional fossil or species we saidh H we said and we we used oropithecus uh Africanas sorry oropithecus cereba but we said also hormonal is a transitional fossil between which two o oropaththeines and homo species would you place this?

[00:21:19]So between which two species?

[00:21:23]Okay. uh in this diagram would you place this? Eh so automatically it's going to be uh homohabilis homohabilis and oropitheicus africanas. So homohabilis because it is between the oropaththeines and homo species. Let me clear it up. we say that it is between or homo species and oropathy.

[00:21:58]So it means that uh it is around here.

[00:22:02]So it is between homohabilis and oropithecus africanas.

[00:22:08]So two marks cheap 50 out of 50. You guys make me proud who got all of the marks. uh those people who are not if we check in our distinction material book we will see that all these things we are talking about they are there yes all these things we are talking about they're there check they're there how many million years ago how I said don't go the paper without knowing this yes which one competed for resources which common ancestor which species competed for resources which one first used the Oh, you see I don't want to go to the distinction material book because some people telling me that whenever there is a question I go back to the distinction material book. Yes, I have to do that to show you that this is a distinction material book is not by talking is by action. All right, let's go to question number two. Diagram shows the chromosome 21 23 and 22. All right.

[00:23:18]Yes. How was this question? Didn't look to be that bad. All right. They're saying that name structure B. Structure B we say that is spindle fibers.

[00:23:29]Structure A centrials.

[00:23:32]Structure C nucleololis because it is found in the nucleus. So now we are done with that.

[00:23:39]Name the type of gamt that is formed at the end of this. We say that if you see that the chromosomes are the same chromosome number 23 they are the same.

[00:23:48]Therefore we say that it is a female. If you see that the chromosomes are not the same the therefore it is a male. So in this case it is a female is a female because the same size. Therefore which type of gamut I will say of they're saying state one function of a during cell division a pulls the chromosomes uh to opposite poles. Yes. Mhm. When the spindle fibers contract but it pulls the chromosome to opposite poles. Identify phase Y. Phase Y is I told you you have to change it so that you see that this and this on the sides. So I'm going to call it uh metaphase metaphase because they in the pairs so I will call it metaphase one metaphase metaphase one metaphase one describe two observable uh difference between the phase identified in above and that of mitosis. If you look at um metaphase one uh we see that here the chromosomes are in pair. You understand? While in mitosis the chromosomes are single.

[00:25:06]Then in this one yes chromosomes uh chromosomes they have variations. You see they have variation. While in metaphase one uh in in in mitosis uh the chromosomes have no variation meaning that they same chromosomes the way they started is the way they going to end. So there is no variation among these chromosomes. In other words here chromosomes have variation while the other side in mitosis there is no variation and any other point which you have pointed out.

[00:25:44]So that as long as it's feasible and then here they said just write the differences. Doesn't matter whether you drew a table or you just wrote uh there's no mark for table because they didn't say tablet. So if they said tableate then that's when you draw a table and then you get a mark for that.

[00:26:01]Explain the chromosome number in phase represented in Z. Ah what are they talking about now?

[00:26:11]Oh yes. So if you look at this question uh we see that this cell is supposed to divide so that this goes to one cell and then this one divides also goes to another cell. Unfortunately after dividing we see that this cell is supposed to be like this. You see?

[00:26:28]Uhhuh. And then this one was supposed to go to another cell but unfortunately this chromosome number 22 went to one cell. then it means that there was non disjunction of chromosome number 22. So what can I say? If they explain the number uh the cell has four chromosomes instead of three. That's point number one.

[00:26:53]This is uh it remains that then you tell us that uh there was non disjunction uh of chromosome number 22.

[00:27:04]there was none disjunction of chromosome number 22 resulting in the the whole set of chromosome to go to h one cell. Yes.

[00:27:14]So basically they say that explain the number. So it has four instead of three and then number two there was n disjunction of chromosome number 20 20 20 22 uh and then resulting in this cell having an extra chromosome number 22.

[00:27:33]So uh we go to the next question which is question 2.

[00:27:41]So describe the process of transcription. Remember here we say that don't go to the paper without knowing transcription. So here you tell us that um double helix DNA annoyance we hydrogen bonds break form two separate strand uh one acting as a template for formation of so you see double helix DNA an weak hydrogen bonds break to form uh two separate strand one acting as a template for formation of messenger using free floating nucleotides messenger and nucleotide from nucleoplasm a complimentary strand is formed so you have to explain this process there's nothing here I can change if you don't know it you take a screenshot whatever you see different color means a marking point if you skipped one of that then it means that you have lost a mark okay so here I'm not going to uh waste too much time there let me go to the table below shows the amino acids and their codons yes I saw this question uh it was a little bit challenging and I told you that this question is going to come but it's going to be a little bit challenging little bit just a little bit not that too much. This [clears throat] page was not that nice for all right we say that what is a codon codon we say that three bases three bases formed on messenger RNA remember codon three bases messenger code three bases on DNA and codon three bases on on transfer RNA so yeshuh DNA base triplet for methion if you look at methion but they're looking for DNA.

[00:29:22]What do you have here?

[00:29:24]Amino acid. And what do you have here?

[00:29:27]Codon. Where do you find codon?

[00:29:28]Messenger RNA. So if they are looking for DNA, then I have to convert that. So methon is here. So the base for DNA is going to be is going to be T A C T. We said T yesterday.

[00:29:45]Anticodon [clears throat] for aspartate. Aspartate or aspartic acid anticodon this is anticodon on transfer a what do you have here messenger so I have to convert this into messenger therefore it's going to be c u it's going to be cua it's going to be cua then they're saying amino acid carried by amino acid carried by tRNA carried by tRNA with antodon this uh tRNA with anticodon because they said is antic-codon therefore I have to change it into codon whereby they say that u g a have to convert into codon which is going to be a cu cu a c a c a cu which is triionine. So the answer there in this case is going to be triionine triionine.

[00:30:44]Yes. So that is the answer here. Try 9.

[00:30:48]So you have to know that.

[00:30:54]Okay. Then we go to the next question.

[00:30:56]Uh they are saying that yes. Now let's go to the question. I say that yeah it will come and if you don't see it the mutation it will come. So there we go. The mutation is here. Name the type of mutation that occurred. We said yeah previously yesterday we said that this is gene uh mutation uh though yesterday we said it's mutation but I say that it can be gene mutation or point mutation so people who wrote gene mutation or point mutation you get the answer during which process could DNA mutation occur when does this DNA they say DNA mutation but they said the mutation occurred on DNA molecule so it only occurs on DNA a molecule when during DNA replication.

[00:31:46]DNA replication. Name the DNA base triplet for glycine. Name DNA [clears throat] best trip plate for glycine. Glycine. Glycine.

[00:32:03]Okay. Now the food is here. Now let's start. It's time to to apply glycine.

[00:32:13]But here we have two of them. How will I know that this will going to be for glycine?

[00:32:19]Okay, we go back and read the question.

[00:32:21]What did they say? They said that imitation occurred on DNA molecu where one nitrogenous base h was affected one. So I have to look for what changed there. It must be one nitrogenous base. If you don't know what changed, you won't get the mark. That's what I said. This caused the amino acid serine to be replaced with glycine.

[00:32:44]Serine. Now it mean that I'm going to go to serine and see that one which made it to have glycine. So go back to serine.

[00:32:53]Serineh.

[00:32:55]Let me first clean up here and they say serine is here. It's also two but they formed glycine. But if you look at this, this and this they are different. This and this they are the same. This and this they are different. So here they are two of them. So it can't be that this and this they are the same. This and this they are the same. This and this they're different. So it means that it is this one which changed. Okay. Now since I know the amino acid which changed because we see it is this one. Even this one changed but here they said only one amino acid only one base changed. So since now I know that this was replaced by this. So it means that glycine is G g but this is codon. What did they look for? They looking for name the DNA base trip plate for glycine meaning that they're looking for DNA. Therefore uh this is messenger I have to convert it into DNA. So it's going to be CCA. Ah so the answer becomes C c Ah two marks explain how this mutation will be will affect the protein formation protein formed. Explain how this mutation will affect the protein formed. Uh since these two marks now I need to know what happens. Uh this mutation will affect the protein formed. So we need to know are they different amino acids? Yes. You tell us that um a different amino acid a different a different a different amino acid was uh was was was carried or was formed. Yes. Uh resulting in a different different protein. Yes. So basically here I'm looking for different amino acids. Yes.

[00:34:48]It means that serine instead of no no glycine instead of serine meaning that a different amino acid was brought to the ribosome. You see number two since is a different amino acid or this code for different amino acid resulting in a different protein that's why you have two marks different amino acid different protein two marks done [clears throat] yes I liked this question they say in both sex is controlled by sex chromosome Z and W chromosome W is short and zed farmer a female bird have zw chromosome and the male bird have zed chromosomes okay you need to understand they're not saying they are carried yes sex chromosome they're not saying sex linked sex chromosome the same way saying that sex is determined by x and y in the [clears throat] so now what can we say here so we're going to say that use the genetic cross to show the percentage chance of having female offsprings in birds.

[00:36:03]Okay, let's see female offsprings in birds.

[00:36:13]So in this case, we're going to say let me create a space I think because this one is not going to be enough for me. [clears throat] I need to know that male percent chance of having male female of having females. They say the females birds are like this and male birds are like this. Simple. This is was just a simple question. Get marks for free. It the question. Ah, let's see. Let's see.

[00:36:40]Let's see. Let's see. Let's see what we said. We said the first step you need to do is to see P1 F1. We give you a mark phenotype.

[00:36:54]Pheno phenotype.

[00:36:57]Uhhuh. Then we say that we go back to the question and look for the phenotype.

[00:37:01]They they said cross a genic cross was shown. What did they say? They said a female B and then male B. So I'm going to say I'm going to say what am I going to say? I'm going to say female. I'm going to say female.

[00:37:16]Sorry guys, something here. I'm going to say Mhm. female.

[00:37:23]Okay. Male bird crossed with female bird. Good. And then genotype. Genotype is going to be is going to be is going to be genotype. We say that male male female is Z W and male is Zed. Female Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z Z and females Z W then you say meiosis meiosis takes place we form the gamut Z W circle circle circle circle we say these are gamts after that we say that cross them I told you that to make this simple put a dot a dot a dot a dot this with that join the dot What's Zed this with that Z W this with that Z zed this with that Z W we said these are offsprings and then how do we call this we said these are fertilization so you guys wrote meiosis and fertilization we give you another mark we give you a mark there before even start marking the real thing we get this from the question that's what I said we give you another mark there then after that we can give you another mark here. So now since they're looking for the the percentage, it could be a compulsory mark. So I said that the phenotype phenotype I need to know the phenotype this and this those are males two males and then this and this these are females two females. So but they want the percentage. So it's two out of four * 100 * 100 which gives me 50% chance. is the same as in humans. 50% chance. All right, you getting six marks. Simple.

[00:39:17]Describe two structure difference between two structure difference between between two structure between the sex chromosome of birds in humans and those of birds. All right.

[00:39:37]H first of all in humans we use XX and X Y X Y for female for male XX for male isn't it? Yes. Meaning that uh in humans let me be clear like this. Let me first start with this. In humans, X and Y are used for sex examination. While in birds, Z and W are used for sex domination. That's number one. Number two, in in humans, XX the one which look alike is for female.

[00:40:26]While here, Zed, the one which look alike is for male.

[00:40:31]You see they said it here it's just a swap they just swapping [clears throat] and then guess what in human h in human y is shor while in in in this w is shorter. Yes.

[00:40:51]So the one which is short in humans h the one which is shot in humans actually goes to the male. The one who is shot in in in birds it goes to the female.

[00:41:01][clears throat] Imagine imagine it means that in in in these birds the the the males are more complicated than females.

[00:41:10]While in humans the females are more complicated than males. Actually females are more I don't know how which percentage because even they don't know themselves. You can be with someone for 20 years but you still don't know. So you guys who are married don't tell me that you know your wivesh you don't know it's just the chapter is just starting it's because of they have xx where now you have x y and y is carries less characteristics anyway that's life without the next question you know guys is life is good life is good this is I don't know how you you going to call it call it whatever you want to call it cuz some people said Hey, you don't know how to pronounce this word. So [clears throat] what is an oral genetic disorder caused by the dominant all a this genetic disorder lead to a form of dwarfism.

[00:42:05]You know that offspring who inhal dominant al died during the baby or infant stage. Offsprings who inherit h both dominant ll they die. Sure that's bad man state. What is a dominant al? A dominant al is an al which expresses itself in a phenotype in a hetererozygous state is an al which expresses itself in a phenotype in hetererozygus. We want to see those two words in hetererozygous state. Mhm.

[00:42:51][clears throat] Go and check our distinction material book or the what we discussed yesterday.

[00:42:56]How many genotypes how many generations are represented in this diagram? How many generation we said is one is two is three. So three. We said three. Yeah.

[00:43:09]Yesterday we said three.

[00:43:11]Three. They're saying that the phenotype of individual number two. The phenotype of individual number two. So they said individual number two you come back here and is a female with this disorder.

[00:43:26]Female with this dis. Don't say affected female affected with what? malaria [clears throat] or hunters they call it hunters what or Ebola okay [clears throat] they're saying that the type the genotype so done the genotype of one genotype of one now look since now now we are going to the the moment to talk about genotype look at the babies remember this is caused by a dominant al dominant all they said it and I said it yesterday that some are caused by dominant all so dominant So meaning that this one is like this.

[00:44:02]Even this one is like this. Even this one is like this. However, I don't care about this because this one just married. So this one and this and it's not sex linked. So it's oral. We said oral not sex linked. So it means that if this one is dominant is capital A and this one is also capital A. But they have kids who have small A small A.

[00:44:21]Automatically this one is like this.

[00:44:22]Even this one is like this. Therefore individual one is going to be capital A small A. Number of individual that are hetererozygous. Number of individuals that are hetererozygous. State the number of individuals that are hetererozygous. They're not talking about the kids. Uh-uh.

[00:44:40]They're just talking about number of individuals. So is is is one is two is three. However, this one we don't know.

[00:44:49]But there's high chances 50% chance that is hetererozygous or is homozygous.

[00:44:53]Because if this and this a from the mother and a from the father you see that this one is going to be like that or if a and this a and this is going to be like that. So you see it can either be 50% this 50% this but because there is probability of this being like this would have known if we have another child here but we don't have that child.

[00:45:14]So you have known that since it's not there so automatically I'm going to say there are three [clears throat] there are what individuals who are hetererozygous three which is which is this one this one and that one let me clean up clean up clean up the mess man all right by the way guys do you know that life science is so nice I feel life science you know I don't know yo yo yo yo life is good Let's go guys without without wasting time. Individual six and seven had $1 X. Five maxi for what man?

[00:45:55]Okay.

[00:45:57]Seven.

[00:45:59]Six and seven.

[00:46:02]Yeah. Yeah. Yeah. Six and seven. All right. Write six and seven in the in the comment section. Six and seven. Six seven. Okay. It means that this is eight. All right. H we are going there guys. It's not me who said that. It's the paper. Uhhuh. All right. We are saying that individual six and seven had one daughter. Explain her phenotype.

[00:46:26]Since they said explain her phenotype, they didn't mention the phenotype. The first mark from those five marks is going to go to telling me the phenotype.

[00:46:35]If this is like this and this is like this, automatically this is like this.

[00:46:39]So first of all I'm going to say that uh individual A is a female who without this disorder.

[00:46:49]That's number one. Number two uh he this individual is homozygous homozygous recessive meaning that if you don't write that you say that this individual is small a small A another mark. So those are two marks. So how many max are we remaining with three?

[00:47:11]Then you tell us that this individual A, this individual X inherited one recessive al from the father and another recessive ll from the mother.

[00:47:28]Those are another two marks.

[00:47:30]You understand? Yes.

[00:47:33]So making the individual to be female without does disorder.

[00:47:41]So first of all is a female without the disorder. The he has this this uh al homozygous recessive meaning that small s a yes. So he in this individual inherited one recessive al from the father and then one recessive al from the mother making them to be uh becausehuh because the parents also uh six is more s and then seven is more s a meaning that yeah so you get the five marks. So you mention the the genotype of this these two parents are both homozygous recessive. The individual is also homozygous recessive meaning that it receives one recessive alert from the father and one recessive alert from the mother. So one mark mentioning this, one mark mentioning this, one mark mentioning uh one from there, one mark mentioning one from there and then the last mark is to talk about what is the phenotype of this individual because they didn't talk about what is it you get the five marks and I explained this I explained this several times though our our answer was our question was a little bit uh in a different passion.

[00:49:01]All right guys, let's go to question number three. Who got 50 out of 50? Oh, who would have got 50 out of 50? All right, we got to number three. In a parent test, investigator first analyzed the blood group before they conducted DNA profiling. The parent test was done three uh for three was done for three males. Okay.

[00:49:26]Okay. Identify all the possible genotypes of male three. Male 3 how many marks is two marks? Then it means that there must be answers is blood group A.

[00:49:36]We said that blood group A has two alternative. Either blood group A homozygous or blood group A heterrozygous done two marks. Explain why the investigator excluded individual two profiling five marks. There is no shortcuts here.

[00:49:55]Now I have to write here. I am not writing. Let me just explain it. Five marks.

[00:50:01]First of all, now I need to go remember I said that when you're doing DNA profiling patented test uh using blood group and this profiling first of all you need to see who is the possible father and then blood group helps us to eliminate out now. So let's eliminate this person out.

[00:50:22]That's what they are looking for. The child is blood group A. You understand?

[00:50:28]Meaning that this child is blood group A is blood group A B. It means that this child now that's one mark. It means that this child uh either got A from the father from the mother or B from the what? This al for B from the mother because the mother is AB also.

[00:50:52]Okay. Now step three that's number two mark number two. Now we say that if this child obtain a from the mother then automatically obtain the second a uh the second b from indivi from marrow one meaning that we all got it from me one.

[00:51:14]Okay. Number three all these are alternatives. If this child obtain B from the mother, yes, then automatically it means that obtain the second uh a the the other A from individual three.

[00:51:31]You see then number three, the last blood. Yeah, there is no chance because the the child is AB there is no the child has no AL for blood group O. You see meaning that there is no chance for individual number male number two to be the father of the child. So we have excluded out this individual. That's why we didn't even bother to go for DNA test for him.

[00:52:03]Remember I said that blood group only helps us is not conclusive only help us to eliminate out those individuals. All right. Explain why the mother was so that's why you have five marks. You see that's why you have all those five marks. Hey guys, better register for extra classes and also better register for our distinction material book because it has everything. Yes, you can order it from us or you can click the join button there and then you can access it. You can access the online version. All right. say that according to DNA profiles which male 103 is the father according to the DNA profile. Uh-uh.

[00:52:47]There's something which we have known.

[00:52:49]Explain why the mother was included in the DNA profile. We had to include the mother so that we able to compare.

[00:52:57]Yes. The DNA profile. Did I say profile of blood group was included in the DNA profile? Yes. We have to compare the DNA profile of the mother with a child first to remove all the DNA profile uh of the mother which correspond with the child.

[00:53:19]Is it clear? Yes. So that now the remaining profile DNA profile or bands Yes.

[00:53:26]can match with any of the what of the parent of the male parent. Yeah. So basically is to compare the the DNA profile of the mother and the child so that we can compare the remaining DNA profile of the child with the possible father. That's it. According to DNA profile which one or two is the father.

[00:53:47]So this what why we include individual number two. And now it is here we have to do it. We have to compare child and mother. You see uh this this. So now the remaining must correspond with the the possible father.

[00:54:10]This must correspond with one of the father is this one. And then this is this one. So it means that individual three is going to be the father.

[00:54:22]Individual three. Step one uses other uses of DNA profiling. We have talked about this. We can do for for instance here to identify the for investigation on the crime scene uh dead bodies a lot of uh DNA profiling you can check our distinction material book because that is just a a straightforward question yeah all right let's go diagram below shows how biotechnology all right told you biotechnology is coming but I used the dolphy dolly What do she All right. Diagram shows how biotechnology can be used to produce a cow a desirable characteristics. Okay.

[00:55:10]Nucleus of the cow removed and discarded. Okay. Mhm. What is bio technology? Biotechnology we say that biotechnology is a a a way is basically a way how we can manipulate the the living organism so that we able to satisfy a a specific need of human. So biotechnology is the use of living organism or is the way of use of uh a component of living organism to make or to modify. It depends on how you you you just choose. This is the way of uh to use living organism. Yes. To modify a product, improve a plant or animal or develop microorganism for a specific use or you can define it in any way you want it to be defined. Yes. As long as it is correct based on the book you have been using.

[00:56:15]Name the biological process represented in the diagram above. So we call this one cloning.

[00:56:23]Cloning.

[00:56:24]Yes, we said cloning. Give one reason why the OAM is used during this process.

[00:56:30]The Oam used as a receptor is the Oam.

[00:56:34]Did I say? Yes. The OAM, this empty is just to receive this nucleus. So we can say that is used as a receptor.

[00:56:44]Why is electric shock? We said that electric shock is used to fuse the oven the oven h the with the nucleus so that it can stimulate the cell division. Yes. It's basically stimulates the what? The cell division.

[00:57:04]Uhhuh. State why uh the offspring produced is phenotypically different from the surrogate mother. Yes, we they are different because they did not use the nucleus of the surrogate mother.

[00:57:19]They different because the nucleus of surrogate mother was not the one which was used. Give one possible disadvantage.

[00:57:28]uh of having all cows uh on a farm produced by Yes.

[00:57:34]Erh [clears throat] all these cows can die if there is a disease for example or a disaster. Yeah.

[00:57:40]Because they are not different from one another. No variation no variation among these cows. Therefore, any disease which approach encroaches the the the what the farm can kill all the what the cows because they are genetically the same.

[00:58:02]That's why we have to be different. You are not the same as your brother. So meaning that you and your brother or your sister or your husband or your wife whatever even if you are related brother and and and and sister you are different God did did it like that so that you're able to survive differently. So people stop saying that this one took my thingy this one took you survive differently.

[00:58:31]Yes. Because of that variation, even the identical twins, they have some ways in which they differ from one another.

[00:58:39]You'll see one is big, one is small, one is angry, one is they have also some differences. All right. We say describe speciation through geographic isolation.

[00:58:49]I this question I brought it and I emphasized it and I told you is coming and I said that this one is a generic question which has no example to use.

[00:58:59]You just have to explain and but however mine was six marks it was seven marks.

[00:59:04]It was seven marks and theirs is eight marks. So and when we are discussing we say that it has more than that. It has something like uh 10 points. So let's go back and then we see uh what did we say about this?

[00:59:19]Yes. What did we say about that? Uhhuh.

[00:59:23][clears throat] We said that it's now here. We said that you just explain this as this. Yes. Here is the describe uh the formation of new species uh using speciation. Yeah, that's it. That's it.

[00:59:38]That's what they want. Only this different mark a population of a particular species may become split into two by geographical barrier. They said for example a river and mountain. As a result, the two parts of population cannot interbreed. There's no gene flow.

[00:59:55]Yes, there is no gene for meaning that there is no sex yeah between them.

[00:59:59]Natural selection occurs independently meaning that they cannot have any natural selection because they cannot interpret. Uh this is occurs independent due to different environmental condition. As a result the two population become genotypically andotypically different. Even if the two population mix at a later time they will not be able to interbreed again to produce fertile offspring. Therefore, one or two become new population sorry new species. This is what they wanted there. If you count how many marks there are more than even eight.

[01:00:38]All right, we got the next question.

[01:00:43]Then this question uh that question is here. Uh that question is here uh is here.

[01:00:53]So what are they saying? They saying that uh they saying that distinction mu will kill you. They're [clears throat] saying that and also we also did it with the the discussion we uh the other one. Okay. Uh there is a video which we did we kept on playing it so that you able to remember.

[01:01:13]But name the type of evidence for evolution representing diagram above. So how do you call that? We call it modification. Modification. Modification by decent.

[01:01:28]Yes, modification by descent. So this is what we are talking about modification by decent comparative anatomy which we call modification by descent.

[01:01:40]Then they brought they brought they brought yes they are saying that explain how this structure are used to as evidence of evolution. First of all this structure they have the same anatomical plan. Yes. Yes. They have the same anatomical plan which show that they share a common ancestor. Same anatomical plan. One mark share a common ancestor. Second mark. Yes. Uh but they they occupied different environmental condition resulting in conver divergent evolution. Yes. So this is it. Yes. This this deal with the similarities and differences of anatomic. You see anatomy of different species. Organisms with the same ancestor. Yes. They have the same anatomical plan. Meaning that they share a common ancestor. Same ancestor, same anatomical plan. Yes. But what happened?

[01:02:37]But they are different due to divergent evolution. They're different because they move to different environmental condition. Therefore, they diverged.

[01:02:47]Mhm. When when you go to water, what do you how do you move? You [clears throat] swim like a fish and then the tree monkey and then the air bird you see.

[01:02:57]Mhm. State one way in which the form of the mall and the mall is is modified for digging. We see that here based on this it has fanges with clothes for digging. Then they saying that different from said one way in which the form of the mall is different from that of African A is different from that of African A. They not saying about this H basically that the mall has clothes while African apes has nails. Has nails have nails. Yes.

[01:03:38]Yes. They didn't say human, they said African ape. And if you look at the African ape even it's its fanges are longer compared to the what that of the mole but they have clothes while African apes they have nails. All right question number three was a little bit longer. Ocean temperature have been increasing due to climate change. When the water temperature increases, oxygen concentration when the water temperature increases. Yes, the oxygen concentration decrease. Okay, this is a pressure. When environment temperature increase, when the water temperature increase, the oxygen concentration decrease, the fish with bigger bodies need more oxygen. Okay? and uh for metabolic activities and uh and decrease in a decrease in oxygen therefore lead to the decline in individual performance okay such as avoiding the predator searching for food etc which decreased the chance of survival in 1970 to 19 when I was I think 20 years yeah marine biologist conducted an investigation to determine the effect of water temperature had on average body adult body size of the commercial fish species. The fish uh species is sold for food by sea food companies by growing the net nets and are used to catch the fish and mainly bigger fish.

[01:05:30]and bigger fish are trapped and the smaller fish mhm escape.

[01:05:38]Okay. The results show the decrease in the average uh body by the size of the fish species over years.

[01:05:48]like investigation was done to effect of temperature that had on the average body size of the commercial fish. All right, let's go. H independent [clears throat] variable of the investigation. They said it here. They said it here that it was conducted to determine the effect ocean temperature ocean temperature.

[01:06:17]The effect of ocean temperature.

[01:06:21]What are the effects of temp? Basically here they are looking at that what will happen to the ocean temperature uh on the size of the body. So the size of the body will depend on the ocean temperature. State one way in which the marine biologist ensure reliability.

[01:06:37]How did the marine ensure the ability?

[01:06:39]He did this thing over years from 1970s to 19 to 20 2014. This is a long period.

[01:06:47]Keep on repeating, repeating, repeating.

[01:06:49]They're saying that explain why the higher ocean current temperature result in a greater proportion of fish with small average body size. Uh-uh. Five marks. Oh, they want natural selection.

[01:07:00]You explain natural selection. So, in this case, you want to explain and you tell us that.

[01:07:07]Okay.

[01:07:09]H but they don't want natural selection direct. They want you to explain to us.

[01:07:15]Okay, first of all, fish. Oh, they um [clears throat] they start saying that here we see that here that when the temperature increase the there's a decrease in the concentration of meaning that there was variation among these fish. Some fish had the ability uh big some are big some are small. Yeah. Yeah. So but now the one which are small survived the one which are big they they they they died or they were eaten. Yes. So there was variation among these fish uh that basically this these fish some were big some were small. Yes. But now due to uh this temperature Yes. Due to this temperature it increase the oxygen the temperature increases the oxygen concentration decrease meaning that due to temperature the oxygen level decreased. Yes decreased and the big fish yes they required more oxygen but the oxygen was not there. There are four they started to die in large numbers because they cannot have metabolic reactions so that they able to have enough energy to avoid the predators and search for food.

[01:08:40]So basically the big fish the big fish they died. Why? Because they had shortage of oxygen. The oxygen which was there was not enough for them for their metabolic reactions so that they able to avoid the predators and also to search for food.

[01:08:59]While the small fish they survived if they survived then it means that they're able to protect themselves.

[01:09:11]How? because they're able to use that oxygen for their metabolic reactions to avoid these predators and they also were they able to search for food.

[01:09:23]So they survived they reproduced in large numbers. they pass the alert for uh the small body to the next generation and then it resulted in the next generation having more fish with the small body than the fish with large body. So basically what caused this is because of the decrease in oxygen and their side their size determined who survived.

[01:09:53]The large fish large fish they died in large numbers because there was decrease in the oxygen concentration. Therefore their metabolic rate decreased. They couldn't run away from the predator and they couldn't look for food. Therefore they died in large numbers. What a small fish the o the oxygen which was there was enough for them. They could do their metabolic reactions. They could run away from predators and they could look for food. And then uh they they they survived. They passed this gen we call this one natural selection. They passed this al to the next generation. The of small body to next generation. So that now the next generation had more proportion of fish with small body than those ones with large body. That's it.

[01:10:39]That's what they wanted here for five marks. And yeah, I see that this one was a little bit challenging, but it was an application question for those people who can yes look at it and uh look at it and then kill it. All right. The use of dring nets by fishermen could have and could could have affected the validity of this investigation. the use of uh of drilling fish by the fisherman could have Yes. Because now not all fish were being caught. Some also were uh were were what were were escaping. Yes.

[01:11:23]So, so that is the reason why uh it was not that much more valid and uh if I can explain it uh in much more better sense. Uh look uh they say that uh this we we are trying to study the effect we are starting to study the effect uh of ocean temperature on the average adult average adult uh average adult body sized commercial fish. You understand?

[01:12:10]And then now the dreading fish also is is is is selecting is selecting out some of these fish. So how will you know that uh the disappearance is as a result of heat or as a result of this kind of fishing. So meaning that there are some fish which are also being removed from the what from the ocean due to the method which is being used which is selective. It only selects out only selects out the what the large the large fish. You understand? Yes. So uh it makes it to be not that much more uh valid. Why? Because uh you refer to get the actual cause of these fish disappearing. Whether these fish are disappearing because of the the the fishing or the contributing factor as draing uh nets or the temperature. Yeah.

[01:13:05]So it makes the the results known to be what uh much more valid. Let's go to the next question which is 3.6.

[01:13:14]The table below shows some of the homminid forcil found in different parts of the world uh that are that are used as evidence of out of Africa hypothesis.

[01:13:24]So here you have also africanas homo erectus and homo sapiion. Mrs. Okay. Sh they're saying that state out of Africa hypothesis. We said modern humans originate from Africa and migrate to the other parts of the world. Yeah.

[01:13:40]So the word modern must be there. If you don't have the word modern then it's gone. Use the information the table describe how the fossil uh fossils of homo erectus and homo sapiens support out of Africa hypothesis. We said we said that uh fossil of the oldest fossil of homo erectus and homo sapiion were only we are only found in Africa but they said use the information in the table. So the oldest fossil of homo erectus and homo sapiens were only found in Kenya which is Africa. Yes. Kenya and then uh the oldest the oldest and then homo sapiens uh in South Africa. You see yes the oldest because if you check it if you check it here you see that uh age this is 1.9 million years ago and then it's just recent and this is uh million years ago and then this just recent. So the oldest fossil of uh Homo erectus uh was found in Kenya. [snorts] And then here the oldest fossil of uh Homo Homo sapion was found in South Africa. You see? Yes. So because they said use the information. Yes. Because Yes. H according to our distinction m book it indicates that you you say oldest. So your job here was to come and find out which one is the oldest of which uh the oldest fossil and then now you're going to have to tell us now. So now we are busy doing what the application. Okay, let me now repeat and I say it how you supposed to write it. Then you say that the oldest fossil of homo erectus which is turana boy was discovered in Kenya or Africa and the oldest fossil of homo sapion which is flor man was discovered in flor South Africa that's it so they I want you to talk about this. One mark, one mark, one mark, one mark. This belongs to this, this belongs to this. Done. Four marks.

[01:16:10]Name two. Name the science who discovered Misplace. Misplace was discovered by Robert Bloom. By Robert Bloom. Yes, Robert. Mrs. Place was discovered by Robert Bloom. They are saying that name two other African species discovered in South Africa. We say that Africana species we say that little food and home child. That's what we said.

[01:16:40]So you guys Yeah, I think name two other Yes, I see that guys. And they brought exactly uh what was happening here.

[01:16:53]I saw this. I liked it also. I brought exactly what is here from still our distinction material book. If you look at it, it is it is exactly though it's different color here they just talked about. So they only just brought only this this part then this part also and then they started firing equation. You see, you see homoanththerosis, homo sapiens, hormones, homo sapiens, homo erectus, homo erectus, homoabilis, homo oropicus and then also africanas and then homo um oropithecus apherences. So they stopped here and then they started to fire question. So you guys those people who are using this material book I know that you guys think you made it. You didn't disappoint me. Uh those who want to upgrade repeat to do what join us [clears throat] on our extra classes uh thunder eduk yes with a small fee. Yeah, if it is private classes, but if it is just normal classes, yeah, then it's fine. And then uh yes, I think that's it guys. Thank you so much for joining, watching. Wish you the best in your life. We pray that that guys everything comes out right according to the plan so that you guys you achieve and become successful in your life. We pray that you guys you become successful. That's what we want from you and our happiness to see that you guys will achieve what you wanted to achieve. Thank you so much for joining Thunder Eduk. It has been Midh trying to do the views according to this paper and according to this paper we see that we predicted it 99% our paper we gave you to practice with it had all the questions all the questions those people who read it on time I think guys you made it and then you killed the paper. Thank you so much. See you again in the next class.

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