In a previous HealthTree University lesson, we explored the function and structure of DNA. Now it's time to zoom in on the chromosome. In this lesson, we'll break down its composition, location, function, and intricate structure. Get ready to uncover the blueprint of life at the next level.
What is a chromosome? How many chromosomes do we have? A chromosome is a unit of organization of your DNA. We have 23 pairs of chromosomes. So you know that the DNA is essentially the central command in the cell. So all major decisions about identity, about life and death are encoded in the DNA of a cell. A chromosome is the unit of organization of the DNA of the cell that becomes particularly important or visible when the cell divides. So when the cell divides, the DNA condenses into discrete parts that we call chromosomes. And because this, very well organized and tightly packaged, and because not every chromosome looks like each other, we can identify them and we can detect abnormalities in the structure or organization of DNA that may be linked with diseases and number of diseases. Clearly, cancer is a big part, and clearly myeloma is part of the cancers that whose chromosomal make up is very important.
To learn more about karyotyping, watch the HealthTree University lesson on this topic in the cytogenetics testing in myeloma course. 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 dad, one chromosome copy, one from mom. So you're a hybrid of your mother and father because you're inheriting these pairs of chromosomes.
Where are chromosomes found? They're located in the nucleus of the cell. So it's a specialized compartment of the cell that really only contains the DNA and not much else. They're free floating within the nucleus until it's time for the cell to divide. And then the cellular machinery inside the nucleus, allows for the chromosomes to line up so that they can be evenly split into new chromosomes.
How are chromosomes structured? Every chromosome, as you'll see in the pictures, has what look like these arms and one. 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.
The structure of a chromosome is. So the DNA is wrapped around these proteins called histones. There are two arms a small arm and a large arm. So the p arm and the q arm in between. There's something called the centromere that is, kind of the center protein that aligns the two pairs of chromosomes together in the cell prior to it dividing into, new cells.
Chromosomes play an essential role in genetic inheritance. When cells divide, chromosomes ensure that the correct amount of genetic material is passed to the new cells. In the next HealthTree University lesson, genes, genetic traits, and genetic inheritance will be discussed.
If you found this HealthTree University lesson helpful, give us a like and subscribe to our channel. You can also watch the other lessons in this course on our YouTube playlist or on the HealthTree University website.
HealthTree • April 3, 2026
