the behavior of chromosome sets in the human life cycle

the behavior of chromosome sets in the human life cycle -...

Info iconThis preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
the behavior of chromosome sets in the human life cycle. The human life cycle begins when a haploid sperm cell fuses with a haploid ovum. ○ The union of these gametes, culminating in the fusion of their nuclei, is fertilization . The fertilized egg (zygote) is diploid because it contains two haploid sets of chromosomes bearing genes from the maternal and paternal family lines. As a person develops from a zygote to a sexually mature adult, mitosis generates all the somatic cells of the body. ○ Each somatic cell contains a full diploid set of chromosomes. Gametes, which develop in the gonads (testes or ovaries), are not produced by mitosis. ○ If gametes were produced by mitosis, the fusion of gametes would produce offspring with four sets of chromosomes after one generation, eight after a second, and so on. Instead, gametes undergo the process of meiosis, in which the chromosome number is halved. ○ Human sperm or ova have a haploid set of 23 different chromosomes, one from each homologous pair.
Background image of page 1
This is the end of the preview. Sign up to access the rest of the document.

This note was uploaded on 01/04/2012 for the course BSC BSC1005 taught by Professor Orlando,rebecca during the Fall '10 term at Broward College.

Ask a homework question - tutors are online