Cells, chromosome, & Cell Division
• Eukaryotic cell with organelles
• Cell membrane• Nucleus• Mitochondria• Lysosomes: Tay-
Sachs Disorder
Cell membrane
• Lipid bilayer• Proteins• Cholesterol• Fluid• Cystic fibrosis:
membrane protein, transport of Cl-
Mitochondria
• Cell Respiration• DNA• RNA• Ribosomes• Genetic disorders• Maternal inheritance
Nucleus
• Chromosomes• Chromatin: DNA and
proteins• Heterochromatin• Euchromatin• Haploid: one set• Diploid: two sets• Homologous
chromosomes
Cell Cycle
• Production of new cells for repair, growth
• Interphase (3 stages)• Mitosis = separation
of chromosomes• Go• Environmental factors• Hormonal factors
Mitosis
Regulation• CDC mutations: 3 checkpoints involved with cyclins• G1/S: cell size, DNA damage, cannot proceed to S• G2/M: Repilication or damage• M: formation of spindle fiber system, not attached
properly• Tumor suppressor genes: P53 program cell death
Meiosis• Only in diploid cells• Diploid to haploid• Replicate DNA once• 2 cell divisions• Production 4 haploid cells• Increase genetic
variability• Recombination• Independent assortment
of homologues• Non-disjunction
Meiosis in humans
Comparison: Mitosis and Meiosis
Genetic Variation
Cell Division Summary
• Mitosis is essential for growth and replacement
• Regulation of cell cycle is important • Cancer is cell cycle regulation with loss of
control• Meiosis produces gametes and genetic
variation• Non-disjunction causes abnormal gametes
and chromosomal inbalance