DNA and Genetics - Angela R

DNA double helix structure

On friday 03/02/2012 we had a speech with Eduardo Camelo that is a teacher of our school. He talked to us about the genes and the DNA of the people. In that speech  i learn that if I take a DNA strand and I stretch it I will have a 2 meters strand of DNA. Also I learn things about chromosomes, one of them is that there are some sex chromosomes; the woman has two x chromosomes and the man has one x and one y, that chromosomes define if is a male or a female. The humans has 23 pairs of chromosomes, (one half is from the mom and the other half are from the dad), but not always is like that, sometimes the people born special and the 21 pair is not a pair, it has 3 chromosomes and the kid has Down Syndrome.

Man with Down Syndrome

The DNA is made by 4 different types of  things, the thymine, the adenine, the guanine and the cytosine. This has a different order in everybody.