New News Biology #51

Meiosis

Gametes = egg cells and sperm cells.

They only have half the genetic material of a normal cell, and this is called a haploid. If two of them combine, it will go on to form a normal cell which will go grow into a new organism.

Every human cell has 23 types of chromosomes, and they each contain genetic info. Each cell actually has two copies, one set from the mother, and one set from the father. Those from the mother are called ‘maternal chromosomes’, and those from the father are called ‘paternal chromosomes’. Each cell has 46 individual chromosomes.

Before cell division, the cell has to replicate the DNA, adding an ‘arm’ to each of the individual chromosomes. When it comes to division, the chromosomes are pulled to the two ends of the cell. The fun fact here is that how the pairs are aligned or divided are random. It means that when the chromosomes are pulled apart, the chromosomes are randomly distributed, and the DNA of each of those cells are different. Now the second division happens. The two arms of each chromosomes are pulled, leaving us with 4 cells from one single cell. These cells are all genetically unique, with tiny changes in the process.

When the sperm and the egg first joined, they formed a diploid cell, then it grows into an embryo, into a foetus, and lastly the fully grown human being.