The longer arm is shown below the centromere and is called the_____.
The correct answer and explanation is:
Correct Answer: q arm
The longer arm of a chromosome that is shown below the centromere is called the q arm. Chromosomes have two arms separated by a centromere. The centromere is the region where the two chromatids are held together and where the spindle fibers attach during cell division. The arms of the chromosome are named based on their length. The shorter arm is called the p arm, which stands for “petite,” a French word meaning “small.” The longer arm is called the q arm simply because it follows p alphabetically.
Each chromosome can be represented as having a short arm (p) and a long arm (q). These arms are used as references when identifying the location of specific genes. For example, if a gene is located on 7q31, this means it is found on the long arm of chromosome 7 at band 31. This naming system allows scientists and medical professionals to communicate accurately about gene locations and chromosomal abnormalities.
The shape and size of the chromosome arms vary depending on the type of chromosome. If the centromere is exactly in the middle, the chromosome is metacentric, and both arms are roughly equal. If the centromere is near one end, the chromosome is acrocentric, and it has a very short p arm and a much longer q arm. If the centromere is slightly off center, creating a longer q arm and a shorter p arm, the chromosome is submetacentric.
Understanding the structure of chromosome arms is important in cytogenetics, a field of genetics that studies chromosomes and their role in heredity and disease. The identification of p and q arms helps in diagnosing genetic disorders, mapping genes, and studying chromosomal changes in cancer and other conditions.