What are they?
Chromosomes are thread-like structures that house DNA.
Where are they found?
They reside in the nuclei of cells.
What do they do?
Different regions of chromosomes function in different ways. Most individuals know DNA to contain our genes. That is entirely correct. Genes are short sequences of DNA that contain information to make proteins. On chromosomes there is a genetic region and that is where these genes are contained. Other regions of chromosomes include Regulatory and Junk regions. For more information about those regions, ask me!
All animals have different number of chromosomes. Humans have two sets of 23- each set inherited from each parent to make a total of 46 chromosomes (duh!). Diploid cells are cells that carry two sets of chromosomes. Almost all animal cells are diploid cells, BUT there are exceptions. For example, sex cells (or sperm and egg cells) are called haploid cells because they only contain one set of chromosomes. This makes sense if you think about it. Since both parents give their offspring one set of chromosomes, when an egg and sperm fuse they each have one set to give to make a total of two sets of chromosomes and... tah dah! We have a baby. Pretty cool, huh? Another exception that I think it really interesting to note it ants. Ants only have one set of chromosomes. Crazy little things!
Karyotypes
The image below is a karyotype. I'm going to throw something at you guys and not discuss it too much further. Chromosomes exist in condensed and expanded states. When cells begin to divide (which I'll talk about in another post) they are in their condensed state and this is the best and easiest time for us to actually see them. So to achieve a karyotype a dividing cell is drugged to stop the division process and a special dye is added. Then the cell is put under a microscope and a picture is taken (with a pretty advanced microscope). Then the picture is cut up and rearranged to achieve this beauty.
http://www.google.com/imgres?q=karyotype&um=1&hl=en&client=firefox-a&sa=N&rls=org.mozilla:en-US:official&biw=1280&bih=642&tbm=isch&tbnid=REhLerngthoByM:&imgrefurl=http://en.wikipedia.org/wiki/Karyotype&docid=qCQCZxZlzltzfM&imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/5/53/NHGRI_human_male_karyotype.png/250px-NHGRI_human_male_karyotype.png&w=250&h=195&ei=wRXhTruCJeqYiAKG8-2TDw&zoom=1&iact=hc&vpx=204&vpy=199&dur=1178&hovh=156&hovw=200&tx=65&ty=76&sig=115968425815851733043&page=1&tbnh=123&tbnw=167&start=0&ndsp=21&ved=1t:429,r:0,s:0
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