Words to think about in this unit. Mitosis Meiosis Chromosomes Chromatids Homologous chromosomes Cell cycle Cancer Haploid vs. diploid Somatic cells versus germ line cells
Mitosis and Meiosis Sea star morula
Sea Urchin Development
In prokaryotes, cell division is simple= Binary Fission forms 2 daughter cells Single circular DNA molecules
Different story for Eukaryotes… WHY? Bigger More DNA many linear chromosomes Packaged differently than prokaryotes Chromosome= long DNA molecule packaged with proteins (called ____________)into compact shape.
OVERVIEW Chromosomes composed of CHROMATIN= Protein and DNA 1 human chrom= 140 million nucleotides 1 chromosome stretched out = 2 inches
Mitosis and Meiosis Mitosis: cell ÷ in somatic cells Meiosis: cell ÷ in germ cells
Cell cycle- cell division and the events that prepare a eukaryotic cell for division
Chromosome When chromosomes replicate, form IDENTICAL sister chromatids. Centromere-connects 2 sister chromatids
Chromosomes (replicated or not) exist in homologous pairs-
Each member of pair carries SIMILAR info!
Cells with homologous chromosomes= diploid cells
Diploid(2n) versus haploid(n)
QUIZ In the cell cycle, what does “S” stand for? What is the definition of somatic cell? What does this picture represent?