hi everyone and welcome back to national 5 biology today we're going to be continuing with unit 2 multicellular organisms and we're moving on to Kiev 3 which is a reproduction it's quite a short key area those are a few things that we have to go over here so we're going to be looking at sexual reproduction throughout the ski area so sexual reproduction requires two parents and the parents have to produce sex cells which we call gametes so sexual reproduction takes place in plants our animals are able to compare them and where the gametes come from later on in this key area so first of all we need to know what these gametes for these sex cells actually are so in males in animals males produce sperm whereas in plants the male gamete is pawn they both to the same function but they're just different things and I wasn't plant and females they're a bit more similar so females the anvil gamete is egg and the female plant gamete is an oval so we'll look at where these are produced later on so these counties these male and female sex cells they have the job of carrying half of the chromosomes for the new your string because if you think about it 50% of your jacket formation comes to your mother and 50 percent comes from your father and these are freed accounts if we look at this in comparison we look at chromosomes and body cells and in the sex cells and the gametes touching on what we've looked at before the previous Kyra so in humans there are 46 chromosomes and their normal body cells however in their sex cells and their gametes there are 23 this is because sex cells gametes have to carry half the chromosomes because they are both going to combine to produce a in this case a 40 sex chromosome zygote but as the term that we use here so the zygote this beginning of an embryo of a fetus of a baby contains 46 chromosomes 23 from the Moller 20 feet from the father that be produced from their gametes so the egg gamete the video gamete and the sperm cell have combined with their 23 chromosomes each temperature says for sex chromosome I could and if you remember we refer to these and have the body cells as diploid with as the SEC tells are haploid and finally the zygote is a diploid and that's good to continue to develop into a baby so if you need a refresher Huckle in the poit hopefully you remember the despot here but sex elves can have the chromosomes from the mother father they are haploid so human sex L would have 23 chromosomes as opposed to a normal body cell a skin cell muscle cell all these sorts of things that have 46 they are double the number so there are some examples here just recap that for refresher so in the four examples I want to identify the haploid chromosome number and the gametes of these organisms so for example if a giraffe if you took a dry skin cell you would find 62 chromosomes so how many chromosomes will you find in their gametes so hopefully you know that then you would find thirty-one chromosomes in their gametes and nurse exhales because they are haploid and that's half the number in a hedgehog you would find 88 protostomes and their skin cells or liver cells or body cells any form at all however in their sex cells you'd find 44 because body cells are diploid and sex cells are haploid again for 130 sets chromosomes and their body cells with mean that there are 18 chromosomes and their sex cells switching up slightly from the Swilly mama if you had a look at the gamete of a woolly mammoth you will find 29 chromosomes which mean how many would you find in any of their body chromosomes and their body cells you'd find 58 because body cells are diploid as opposed to sex cells which are haploid which means they're double the number of the gametes tiger you would find 19 chromosomes and their sex cells hey Mary would be in your body cells p-38s doubled number and finally for some plants which have massively more sets of chromosomes and helble's number chromosomes and their pollen order ovo in our gametes in this case would be sex thirty so when other parts of the plant cell to be 1260 again just showing less BB m ed so looking at but more implant we're going to take a look at where gametes are produced implants and have a look at this diagram as well because it could come up so if any assembly pollen which hopefully remember is the male gamete is produced in the anthers so the parts are sticking up here and towards the top of the diagram whereas ovules are produced in the ovaries what wheels and ovaries send fairly somewhere so hopefully that would be a good way if you remembering that in animals it's a little bit different sperm is produced in the testes so the male gamete is produced in the testes and female server eggs are produced in the ovaries so by easier to remember occurs exactly the same as plants and you could be asked in the exam to stay the site of these gametes productions or what is produced in for example the ovaries or testes finally what we're going to look at is a process of fertilization as importance newest definition so fertilization is when the nucleus of a haploid sperm a nucleus of a half boiled egg fused together in order to form a diploid zygote so going back to that diagram really fat le Ron it's important to remember it's not just a sperm and egg Claydon together it's the nucleus in the sperm and the nucleus in the egg which fused together all that genetic information that has been passed on through the gametes the actual site for fertilization is and oviduct you may have came across as Philippine troops before but we see the oviduct in biology so the sperm and the egg meet together and abduct and now it's really process or fertilization takes place once that fertilized egg which we have said before is a zygote a diploid zygote is fertilized it implants itself in the wall of the uterus and that's where it begins to grow and develop and to an embryo and her fetus and then once it's born into her baby so that's all we need to build for a ski area like I said is quite short and but there are a few new terms and phrases for you to know what I'm going to do is I'm going to add the quizzes underneath and their permission of this YouTube video and feel free to send me a message about or write in the comments for anything else you'd like they're good to be some more videos come up very soon and I'm also going to get on with some more skills questions that people are wanted to do as well so thank you very much for listening and the rest of unit 2 will be coming up very soon thanks very much