Chapter 8
Mitosis (asexual cell reproduction)
Chromosomes (during cell division, condensed)
Chromatin (between cell divisions, dispersed)
Chromatid (a single copy of a chromosome)
Mother cell 1 chromatid/chromosome
DNA replication2chromatids/chromosome
Mitosischromatids split
Daughter cells have 1 chromatid/chromosome
And so the cycle goes…
Interphase: replication of DNA
Prophase: chromatin condenses to chromosomes
Prometaphase: microtubules tug of war on
chromosomes
Metaphase: chromosomes line up at metaphase
plate
Anaphase: chromatids separate
Telophase: daughter nuclei form
Cytokinesis: cytoplasms separate
Cell division must be regulated
A failure of regulation is what we call cancer
Mutagens are potentially carcinogenic
Chapter 9 Meiosis
Sexual cell reproduction
Haploid=1N
Diploid=2N
Homologous chromosomes (pairs of
chromosomes: 23 pairs in a human
223 unique gametes for each person due to
independent assortment
Three sources of genetic variation in sexual
reproduction
1) independent assortment
2) crossing over
3) different sperm and different egg
combination
some organisms, the haploid is the dominant part
of life cycle (e.g. fungi, mosses)