The first step to understanding this diagram is knowing what a chromosome is. A chromosome is a structure that contains DNA, which determines the genetic information for each individual.
There are 23 pairs of chromosomes in humans and one pair of sex chromosomes (X or Y) – so there are 46 total chromosomes in most cells. Chromosomes come from the body’s nucleus and they contain all your genes!
However, chromosomes are not just found in the nucleus. If you open up your cell and look at it under a microscope, you would see that there are also many organelles scattered around inside of it.
The mitochondria are one example – this structure contains DNA as well! This diagram summarizes chromosome packing across different cell types:
Nucleus- all 46 human chromosomes can be seen here (23 pairs of autosomes and one pair of sex chromosomes)
Mitochondria- each type has its own set of genes for energy production; mitochondrial DNA is circular
Chloroplast- these plant cells contain several hundred chloroplasts that use light to produce food from carbon dioxide and water via photosynthesis