Cell Biology: Chromosomes, the Cell Cycle, and Mitosis/Meiosis

Parts of a Chromosome 1. Telomeres - ends of a chromosome; protects the chromosome from deterioration 2. Kinetochore - 3. Centromere - where the sister chromatids are joined together Chromatin Unwound DNA Found during interphase DNA is used to synthesize macromolecule...

Parts of a Chromosome 1. Telomeres - ends of a chromosome; protects the chromosome from deterioration 2. Kinetochore - 3. Centromere - where the sister chromatids are joined together Chromatin Unwound DNA Found during interphase DNA is used to synthesize macromolecule Chromosomes Tightly packed DNA Found only during cell division Somatic Cells: Body cells; diploid; Germ cells: Sex cells; haploid; Ploidy Level: Haploid Vs Diploid Diploid - Cells with two sets of chromosomes - Example: somatic cells - Contains 46 chromosomes - These cells divide by mitosis, creating two identical daughter cells Haploid - Cells with a single set of chromosomes - Example: germ cells - Contains 23 chromosomes The Cell Cycle Interphase - Gap 1 (Growth Stage) - Growth and metabolic roles - Synthesis Stage (DNA Replication) - Gap 2 (RNA and Protein synthesis) - Growth and more preparation M-Phase (Meiosis/Mitosis) - Prophase - Metaphase - Anaphase - Telophase Cytokinesis - splits into two daughter cells Mitosis - Happens in all cells  - For growth and repair - One cell division - Produces two diploid cells - Has 4 major stages Prophase - microtubules appear, chromosomes condense Metaphase - nuclear envelope disappears, chromosomes align Anaphase - chromosomes separate Telophase - chromosomes disperse Meiosis - Produces egg and sperm - 2 cell division process: Meiosis I - Reductional Division; 2 haploid cells Meiosis II - Equational Division; 4 haploid cells - 4 haploid cells Cytokinesis - Division of cytoplasm - Two new daughter cells are now separate G1 Checkpoint: nutrients, growth factors, DNA damage G2 Checkpoint: cell size, DNA replication Metaphase Checkpoint: Chromosome spindle attachment Apoptosis - programmed cell death