what are chromosomes

Chromosomes are thread-like structures located inside the nucleus of animal and plant cells. They are made up of DNA tightly coiled around proteins called histones, which provide structural support. Chromosomes help ensure that DNA is replicated and distributed appropriately during cell division. Each chromosome has a centromere, which divides the chromosome into two sections - the p (short) arm and the q (long) arm. The location of the centromere on each chromosome gives the chromosome its characteristic shape and can be used to help describe the location of specific genes. At the end of each chromosome is a repetitive nucleotide sequence cap called a telomere, which serves a critical role in preserving the genomic sequence by protecting the genome from degradation and inhibiting chromosomal fusion and recombination. Humans have 23 pairs of chromosomes, for a total of 46 chromosomes. Each pair contains two chromosomes, one coming from each parent, which means that children inherit half of their chromosomes from their mother and half from their father. Chromosomes are not visible in the cells nucleus, not even under a microscope, when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope.