Heredity and Conception

Hi everybody,

it's a rainy day outside, so I thought the best thing would be to make a new blog :)
In the last lecture I felt like I was in highschool biology lesson, all these stuff with DNA, genes, zygots...and I realized that I missed that all we've done in highschool a little ;)

What ever I think I should come to the point :D
Our 2nd lecture was on "Heredity and Conception" and this is what I'm going to talk about today :)

When we talk about Heredity we try to observe the influence to the Development . In short the idea of how a baby develops.

Now the idea is simple there is a cell, which is containing chromosomes (23 pair chromosomes, the 23rd pair chromosome tells the sex of the person by the way :D) these chromosomes are composed by DNA containing different proteins, this is called chromatides (one single part of the chromosom is called one-chromatid-chromosom). I hope that I'm not confusing you. And finally the DNA contains genes, which are segments of the DNA, who contain different characteristics of that person that are important for the heredity.

cell ----> chromosomes ----> DNA ----->genes (segments of a DNA)

To build up a human body, these cells need to make cell division and reproduction. For this there is the need of the processes called mitosis and meiosis.
But there are differences between these two kind of cell divisions.
While mitosis is used for cell division of all cells, meiosis functions just for gametes. Mitosis is a normal cell division, meiosis a reduction division. One other important difference is that there is no recombination at the mitosis, but at on the other at the meiosis recombination exists, which is also a danger for faults. Last but not least the chromosome set at the mitosis is diploid, that means each chromosome is existing double. In contrast to that at the meiosis it is haploid, only one part of the "chain" exists.