Bio 100 Chapter 8 part 1
- 1. Chapter 8 Part 1 Mitosis Cell Division and Reproduction
- 2. Chromosomes become visible during cell division A karyotype displays the chromosomes • Karyotype – Display of the chromosomes – 23 pairs of chromosomes – 46 total chromosomes – One member of each pair comes from the father, the other member comes from the mother
- 3. • Autosomes – Have nothing to do with gender – 22 pairs • Sex chromosomes – Determines gender – XY is male – XX is female • Homologous pair – Pair of autosomal chromosomes – Look alike – Carry genes for the same trait (earlobe, hairline, finger length)
- 4. • Sister chromatids – Duplicated chromosome required for mitosis • Centromere – Holds together sister chromatids • Kinetochores – Protein complexes at centromere where spindle fiber attaches during cell division
- 5. The eukaryotic cell cycle has a set series of stages • Cell cycle – Series of stages of cell growth and division • Interphase – Time between cell division • G1 Stage – Recovery from division – Decides whether to divide or not » Enters G0 if it is not going to divide where it will continue normal processes – If it is going to divide, it doubles in size, double organelles, accumulates molecules needed for DNA synthesis • S Stage – DNA replicated resulting in sister chromatids • G2 Stage – Organelle replication continues – Makes proteins (microtubules) needed for cell division
- 6. M stage (mitosis) • Cell division • Chromosomes divided between 2 cells • Cytokinesis – Division of cytoplasm
- 7. Mitosis maintains the chromosome number Following mitosis, daughter cells have the same chromosome count as the parent cell • Parent cell – Original cell • Daughter cells – 2 new cells • When cells enter M stage, it has sister chromatids (duplicated chromosomes) • Animal cell are diploid (2n) throughout mitosis (chromosomes are in pairs) • Some protists and fungi are haploid (n) before and after mitosis
- 8. The spindle apparatus • Centrosome – Divides at the start of nuclear division – Produce spindle fibers, which assist separation of the chromatids as they move to opposite poles
- 9. Mitosis has a set series of phases Early prophase • Centrosomes divided • Chromatin condensing into chomosomes • Nuclear envelope fragmenting Prophase • Nucleolus disappeared • Duplicated chromosomes (sister chromatids) visible • Centosomes begin moving apart • Spindle is in the process of forming
- 11. Early metaphase • Each duplicated chromosomes attached to the spindle apparatus • Spindle fibers stretch from each pole Metaphase • Centromeres of duplicated chromosomes are aligned at equator • Kinetochores attach sister chromatids to spindle fibers that come from opposite poles
- 13. Anaphase • Sister chromatids part and become daughter chromosomes that are pulled toward the poles Telophase • Daughter cells are forming • Nuclear envelopes and nucleoli reappear • Chromosomes become chromatin
- 15. Contribution of the Cell Cycle to Human Health Cell division allows a fertilized egg to develop into a newborn and is also important in repairing damage to your body like broken bones and cuts.
- 16. Cytokinesis divides the cytoplasm Animal cell cytokinesis • Cleavage furrow forms between the two daughter cells • Furrow deepens when the contractile ring forms between cells and continues to tighten • 2 independent daughter cells result
- 17. Plant cell cytokinesis • A new plasma membrane (cell plate) comes between the new cells • The new membrane releases molecules that form a new cell wall between the new cells