meiosis how does sexual reproduction lead to genetic variation This is a topic that many people are looking for. savegooglewave.com is a channel providing useful information about learning, life, digital marketing and online courses …. it will help you have an overview and solid multi-faceted knowledge . Today, savegooglewave.com would like to introduce to you Meiosis | Genetics | Biology | FuseSchool. Following along are instructions in the video below:
Sperm meets egg. Which then undergoes multiple cell divisions to make a living organism with with trillions of cells. All doing their own specialized function impressive.
But we do the and sperm come from the answer is as you may have guessed from the title meiosis first its good to know that there are two types of cell division processes the simpler one is mitosis which produces two identical cells with exactly the same genetic information. You can think of them as clones of each other and to find out more why not look at our videos about mitosis. The other process is meiosis is a much more complicated process creating not two.
But four cells with only half the number of chromosomes and crucially all genetically different from each other both mitosis and meiosis include the same phases prophase metaphase. Anaphase and telophase except in meiosis. They happen twice.
So they usually refer to as one and two the easiest way to remember. These phases names is to remember. It met so lets look at meiosis in more detail as always cellular division starts with a process called dna replication this involves making two identical copies of original dna molecule the cell ends up temporarily with double the normal number of chromosomes you can learn more about dna replication in this video in prophase.
One the duplicated chromosomes join up with the pay from the other parent. So the mothers p bind. With the fathers be forming a group of two chromosomes called homologous chromosomes.
What happens next is vital for successful meiosis as each chromosome is lined up next to its partners p. One chromatid from each side gets entangled with a corresponding chromatid from the other side. This is called crossing over during this brief period.
The two chromatids swap certain sections of dna. This is called recombination. The sections that they trade correspond to the same location so that each chromatid retains a correct number of genes recombination is really important because it creates variety the new cells arent identical to the other parents and they also are different to one another as well they are new genetic combinations in fact thats the whole point of sexual reproduction.
It increases genetic variability each chromatid is not different and as each one will end up in a separate. Gamete and means each sake cell. Is genetically different from all others this explains.
Why brothers and sisters are different despite having the same parents only identical twins have the same genetic makeup. As they both originate from the exact same egg and sperm now back to meiosis next comes metaphase. 1.
As the chromosomes align themselves up in the middle of the cell and in nfas 1. The spindle fibers pull the chromosomes apart to opposite ends in during telophase. 1.
And cytokinesis. The cell pinches apart in the middle. And the nuclear membrane reforms around the 2 new daughter cells.
Thats the end of meiosis. 1. Now for part 2.
We start with our recombine daughter cells each so with 46 chromosomes but sperm and egg cells. Only had 23 chromosomes so we need to cut these cells in half. Yokos a second round of division.
The process is exactly the same as before except that there is no dna replication. We start straight with prophase. 2.
With chromatin clumping again to form chromosomes. Then aligned in the middle of the cell. During metaphase.
2. And chromatids are pulled apart. During anaphase.
2. By the spindle fibers. Telophase and cytokinesis pinch the soles.
Together with four new krandle being formed the end of meiosis gives us four different six cells each with only 23 chromosomes ready for future fertilization. But thats a story for another video. If you liked the video give it a thumbs up and dont forget to subscribe comment below if you have any questions why not check out our fuse graph as well until next time .
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