Chromosome:
A chromosome is a long, thread-like structure made of DNA and proteins that contains genetic information.
Each chromosome has two distinct parts called the p arm and the q arm, which are separated by a structure called the centromere.
P arm: The "p" stands for "petite," which is French for "small." The p arm is the shorter of the two arms of a chromosome. It extends from the centromere toward one end of the chromosome.
Q arm: The q arm extends from the centromere to the other end of the chromosome, and it's usually longer than the p arm.
Centromere: The centromere is the region in the middle of the chromosome that separates the p arm and the q arm. It plays a crucial role during cell division, ensuring that the chromosome copies are properly separated and distributed to the new cells.
In summary, the p arm is the short arm, the q arm is the long arm, and the centromere is the structure in the middle that holds them together.