Cell growth and reproduction is guided by the genetic code present in the DNA strands of the cell. These DNA strands form genes, which are packaged in chromosomes
Reproduction can be either sexual or asexual. In asexual reproduction, a single set of genetic information is replicated in an identical cell. The first step is the copying of a second set of chromosomes identical to the first in the cell nucleus. These two set then latch onto opposing sides of the cell. The cell membrane on these opposing sides continues to constrict until the cell is cleaved down the middle. This method of reproduction produces an offspring that is a perfect clone of the organism. It is the only means of reproduction in single-celled organisms. Some multicellular organisms, such as starfish, can also reproduce this way.
Sexual reproduction results from the joining of two specialized reproductive cells, such as sperm and ova. The advantage of this form of reproduction is that it introduces a larger pool of genetic diversity, as the offspring has two sets of DNA instead of the single set that is copied in asexual reproduction. Reproduction through sexual means involves the cells undergoing a complex replication and division process called mitosis.