To understand answer to this question, one should have clear knowledge on the cell structure. A living cell has cell membrane as the outer boundary wall within which lies all cell bodies suspended in a fluid like cytoplasm. Nucleus is one such body having nuclear wall within which lies nucleolus and chromosomes. Each species of plant or animal has a specified number of chromosomes. For example human cell has 46 chromosomes paired into 23 pairs. Each chromosome looks like a long chain of beads compactly lined up. Each bead is a long chain double helical ladder like DNA molecules. Each bead is a gene and is a ball of long chain of DNA molecule. All the 23 pairs of chromosomes have several beads of unspecified number grouped into several sizes long size chromosome to short size. Totally about