BIOLOGY 1A03 Study Guide - Final Guide: Spindle Apparatus, Chromosome Abnormality, Sister Chromatids

• School: McMaster University
• Department: Biology
• Course: BIOLOGY 1A03
• Professor: Rosa Da Silva

Document Summary

The human life cycle: 2 multicellular diploid adults (2n=46) ovary (from female) and testis (from male) undergo meiosis egg (n)+ sperm (n)= fertilization forms a diploid zygote (2n=46) mitosis and development. Ideally, the mitotic spindle distributes chromosomes to daughter cells without error. In the testes resume mitosis, at puberty, these cells are stimulated to undergo meiosis, continued mitosis and meiosis throughout lifetime. : brief period of mitosis, entry into mitotic arrest (pre-birth), after birth, male germ cells. *note: nondisjunction can also occur in mitosis, but not affect the entire organism to great extent (may become apoptotic) or become cancerous . Nondisjunction leads to aneuploidy: aneuploid cells have an abnormal number of chromosomes, a chromosome contains hundreds of genes, the addition or loss of a single chromosome disrupts cell equilibrium. Down syndrome: chromosomal alteration that results in 3 copies of chromosome 21, affects 1/700 children, developmental challenges, broad face, hands, nasal bridge, wide- set eyes, heart, immune and skeletal system defects.