Thursday, May 26, 2022

Diploid vs. Haploid Cells

Hi it's mr. Andersen and in this video I'm going to show you the difference between diploid and haploid cells and I'm giving you a clue here in the title since diploid is written twice and in different colors it tells you a little bit about what it is but before we get to diploid and haploid cells let's talk about the secret of life and the secret .

Of life is this that the genes or the information on how to make a new you is going to be found in your DNA so the DNA contains genes those are simply sections of DNA that code for specific RNA which eventually makes specific proteins and those proteins eventually make you and so we're going to have around 20,000 genes in human DNA each of those are .

Coding for a specific protein it's a little more complex than that but that's what you're made up of you're made up of proteins and so let's look at a specific chromosome we're here we're looking at chromosome 16 it's the 16th smallest chromosome that humans have and if we die it if we stain it it looks kind of like this it has a short and a long arm .

But if we were to look way down here there's going to be a gene and that gene if there is a specific change in it is going to code for a specific color and that color is going to be red in red hair now there's not just one gene on chromosome 16 there's going to be around a thousand genes just on chromosome 16 and each of those are coding for .

Specific proteins but this one right here is coding for that red hair color now you know however that it's not as simple as that you could have two parents that don't have red hair and they can have a kid that does have red hair and so how does that work well you have two chromosomes you are a diploid organism and so every .

Cell in your body is not going to have only one chromosome 16 but you're going to have two now these chromosomes look the same when you look at them they look very similar and that's because they're homologous chromosomes they're about the same length as centromeres in the same location they're going to have the same genes all the way up and down but .

They're going to just have different alleles or different versions of those genes where did you get those two chromosomes from you got them from your parents and so you got one from your dad and you got one from your mom and so you could have a parent who only has one of these genes for red hair it's recessive and .

It's not going to show up in you and so every cell in your body is diploid what does that mean it has two complete sets of chromosomes and therefore two complete sets of genes and so what cells in our body are like that all the cell's all the cells in our body at least humans are going to be so mad Excel somatic cells means body cell and .

So every cell is going to be diploid or 2n and it's going to refer to the number of chromosomes and so we have 1 2 3 chromosomes in a haploid cell and in a diploid cell we're going to have 2 of each of those chromosomes so we're going to have a total of 6 and so where are the haploid cells those are going to be the sex cells or the gametes and so this .

Sperm in humans is going to have 23 chromosomes the egg is going to have 23 chromosomes each of those cells by themselves are haploid or n but the somatic cells are all the cells in our body the body cells are going to have 46 chromosomes because we get 23 from our mom and we get 23 from our dad and so ploidy then refers to the chromosome .

Sets in the nuclei and so if we were to take a somatic cell or a body cell and take this nucleus here and bust it apart what would we see we would see all these different chromosomes and in this image they've been dyed so you can see the different colors we could arrange them according to length the longest one is going to be chromosome one and it's just .

Going to keep going down like that and this would be a karyotype it's going to show that a cell of a human is diploid it has two copies of every chromosome now what does a karyotype tell me not much it does tell me that I'm a girl in this case that we're going to have two x chromosomes it could tell me if I had Down syndrome we'd have an extra .

Chromosome 21 but it doesn't even tell me if I have red hair it doesn't even tell me what that gene is it just says that I have two copies of the sixteenth chromosome and so in humans the sex cells or the gametes are going to have half of that and so an adult somatic cell or body cell we're going to say 2n equals 46 well what is n refer to it's .

The number of chromosomes and again in humans we have 20 three you can see here's 22 here's 23 but why do we put a two in front of the end because we have two copies of all of those and so if we to look at the gametes oh the sperm and the egg they're going to be N or haploid cells and n is only going to be 23 .

So 23 chromosomes in the sperm 23 in the egg and when you fertilize that egg we're back to a diploid cell again and so you should know this that in humans we spend most of our life being diploid or 2n but it's not the same in all organisms all organisms are going to move through a eukaryotic organisms are going to move through this diploid phase .

And then a haploid phase and so you might think well how do we move from haploid to diploid remember when two gametes come together that forms a zygote and that process is called fertilization so when sperm fertilized egg that fertilization process is going to move up into the diploid region and likewise when we go from 2 n 2 n that's .

Meiosis when we're creating new cells that are haploid or have half the genetic information and it's also mixed up or there's variable in that and so let's look at this human right here so the human adult human is going to be diploid in nature every cell in its body except for its sex cells are going to be diploid of two copies of all the .

Chromosomes how do we eventually get back to another human well we're going to have meiosis where in the mail we produce sperm and female we produce egg but we're quickly going to have fertilization and then we're back into the diploid realm we're gonna have a zygote that eventually gets bigger in forms a new organism and so when you're .

Looking at me you're looking at cells that are diploid what's the advantage of that well one thing is we kind of a backup copy for all our genes if something goes wrong we have another one we also can have variability in that we can have genes like sickle cell anemia that can hang out and eventually they come in handy later on but it's not the .

Only way life is built so if we were to look at algae these algae here which are microscopes microscopic plants most of them are going to be haploid and so each of these only has one set of chromosomes or one set of genes in it what's the advantage of that it's easier doesn't take as long to copy all of that DNA but they still go through the life cycle .

They're still going to have fertilization quick meiosis back to cells that are haploid again and so they're going to just be haploid mushrooms a number of different fun guys are going to be haploid each cell is only going to have one complete set of genes or one set of chromosomes but they still will go through fertilization .

Meiosis back to cells that form a mushroom if we were to look at some of the higher plants like this this evergreen tree here it's going to be diploid all the cells in it are going to have 2n or it's going to have two copies of every gene but it'll still go through meiosis fertilization and then we're back to two with but very simple things .

Like a moss or a liverwort are going to spend a lot of their time down here in the haploid and so again there's variety in life and it's played against um you know the advantages in their specific environment and there are going to be some things where we get you know triploid or tetraploid or polyploid in fact plants are made by having mistakes .

Where we increase the number of chromosomes and it can create a new plant I think there's a type of plant called the death adder that has 1024 ployed so it has so many chromosomes it has so many genes but it still works I'll leave you with a really tough question tough question is this bacteria um what's their ploidy .

In other words are they haploid are they diploid now they're not going to go through meiosis remember they're going to go through binary fission but what are they well the right answer is that they're some water between haploid and diploid and so what's their ploidy it would be like 1.2 or 1.8 well how does that work if you have a bacteria the DNA .

Gets copied really really quickly and so they're quickly going to copy their DNA but it takes much longer to make the proteins that eventually build to bacteria and so if we were to look at all these bacteria some of them are going to have you know one but some of them are gonna have one point two one point eight they're going to be .

Somewhere between the two and so what is ploidy it's going to tell us the number of chromosome sets that we have again it's different in all forms of nature and I hope that was helpful

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