Chromosome regions

Several chromosome regions have been defined by convenience in order to talk about gene loci. Most important is the distinction between chromosome region p and chromosome region q. The p region is represented in the shorter arm of the chromosome (p is for petit, French for small) while the q region is in the larger arm (chosen as next letter in alphabet after p).These are virtual regions that exist in all chromosomes.
These are listed as follows:
During cell division, the molecules hat compose chromosomes (DNA and proteins) suffer a condensation process (called the chromatin reticulum condensation) that forms a compact and small complex called a chromatid. The complexes containing the duplicated DNA molecules, the sister chromatids, are attached to each other by the centromere(where the Kinetochore assembles). 
If the chromosome is a submetacentric chromosome (One arm big and the other arm small) then the centromere divides each chromosome into two regions: the smaller one, which is the p region, and the bigger one, the q region. The sister chromatids will be distributed to each daughter cell at the end of the cell division. Whereas if the chromosome is isobrachial (centromere at centre and arms of equal length), the p and q system is meaningless.
At either end of a chromosome is a telomere, a cap of DNA that protects the rest of the chromosome from damage. The telomere has repetitive junk DNA and hence any enzymatic damage will not affect the coded regions. The areas of the p and q regions close to the telomeres are the subtelomeres, or subtelomeric regions. The areas closer to the centromere are the pericentronomic regions. Finally, the interstitial regions are the parts of the p and q regions that are close to neither the centromere nor the telomeres, but are roughly in the middle of p or q.
Satellite chromosome:.
Satellite or SAT-chromosomes are chromosomes that contain secondary constructs that serve as identifying .They are semmed in ACROCENTRIC type of chromosomes. In addition to the centromere, one or more secondary constrictions can be observed in some chromosomes at metaphase. These chromosomes are called satellite chromosomes. In humans it is usually associated with the short arm of an acrocentric chromosome, such as in the chromosomes 13, 14, 15, 21 and 22. The Y chromosome can also contain satellites, although these are thought to be translocations from autosomes. The secondary constriction always keeps its position, so it can be used as markers to identify specific chromosomes.
The name derives from the small chromosomal segment behind the secondary constriction, called a satellite, named by Sergei Navashin, in 1912. Because it didn't stain with the Feulgen reaction. With time, the term "SAT-chromosome" simply became a synonym and also an abbreviation for satellite chromosome.
The satellite at metaphase appears to be attached to the chromosomes by a thread of chromatin.
They are responsible for the formation of NOR or nucleolar organizing region.