[Music] what are chromosomes how many chromosomes do humans have chromosomes are wound up dna that organize the dna into a tight structure and you can see that every individual every human has 22 chromosomes plus an x and a y they get from mom and dad which determine their gender the x and the y but every other chromosome of the 22 comes in pairs and they come in pairs because if you look at chromosome one you get one copy of chromosome one from dead one chromosome copy one from mom and every chromosome comes in pairs one from mom one from dad so you're a hybrid of your mother and father because you're inheriting these pairs of chromosomes what is the structure of a chromosome every chromosome as you'll see in the pictures has what look like these arms some of the arms are longer and some of the arms are shorter so the ends of chromosomes are called the telomeres the middle of the chromosomes are called centromeres and there are different arms of the chromosome we refer to them as the q or the p arm i'll be honest with you i don't know where that terminology of q and p came from but it's one of those sort of universally accepted that if you talk to a genetic researcher or a clinician about the q arm or the p arm they know which arm you're talking about there's a convention for defining how those chromosomes are organized you