Cell & Nuclear Division

• What is the purpose of mitosis?

  Produces genetically identical daughter cells
• What does meiosis produce?

  Haploid gametes with genetic diversity
• What is a mother cell?

  Original cell undergoing division
• What are daughter cells?

  Resulting cells after division
• What is cytokinesis?

  Division of cytoplasm post-nuclear division
• What are the phases of mitosis?

  Prophase, Metaphase, Anaphase, Telophase
• What happens during prophase of mitosis?

  Chromosomes condense and nuclear envelope breaks down
• What occurs during metaphase of mitosis?

  Chromosomes align at the equatorial plate
• What happens in anaphase of mitosis?

  Sister chromatids separate and move to opposite poles
• What occurs during telophase of mitosis?

  Chromosomes decondense and nuclear envelopes reform
• How does cytokinesis differ in animal and plant cells?

  Animal cells form a cleavage furrow; plant cells form a cell plate
• When does DNA replication occur?

  During the S phase of interphase
• What is semi-conservative replication?

  Creates sister chromatids as identical DNA copies
• What is a centromere?

  Region where sister chromatids are held together
• What is chromatin?

  Uncondensed DNA visible during interphase
• What is a chromosome?

  Condensed chromatin visible during mitosis
• What is the purpose of meiosis?

  Reduces chromosome number and increases genetic diversity
• What occurs during prophase I of meiosis?

  Homologous chromosomes pair and crossing over occurs
• What happens during metaphase I of meiosis?

  Bivalents align randomly for independent assortment
• What occurs during anaphase I of meiosis?

  Homologs separate to opposite poles
• What happens during telophase I of meiosis?

  Two haploid cells form with duplicated chromosomes
• How does meiosis II differ from meiosis I?

  Meiosis II resembles mitosis; sister chromatids separate
• What is the haploid number in humans?

  23 chromosomes
• What are the sources of genetic variation in meiosis?

  Crossing over and random orientation of homologous pairs
• What is the formula for gamete diversity?

  2$^n$ where n is haploid number
• What are recombinant chromatids?

  Chromatids with mixed maternal/paternal genes
• What is nondisjunction?

  Failure of chromosomes to separate properly during anaphase
• What is the result of nondisjunction?

  Gametes with abnormal chromosome numbers
• How does maternal age affect Down Syndrome risk?

  Risk increases with maternal age
• What is unequal cytokinesis?

  Unequal division producing one functional cell and others degenerate
• What is the process of division in prokaryotes?

  Binary fission
• What is a centrosome?

  Organizes spindle fibers in cell division
• What is a kinetochore?

  Protein structure on centromere for spindle attachment
• What are motor proteins?

  Kinesin and dynein that move chromosomes
• What are histones?

  Proteins that package DNA into chromatin
• What are the phases of mitosis and their key events?

  1. Prophase: Chromosomes condense, nuclear envelope breaks down, spindle fibers form.
  2. Metaphase: Chromosomes align at the equatorial plate, spindle fibers attach to kinetochores.
  3. Anaphase: Sister chromatids separate and move to opposite poles.
  4. Telophase: Chromosomes decondense, nuclear envelopes reform.
• What are the phases of meiosis and their key events?

  1. Meiosis I:

  • Prophase I: Homologous chromosomes pair, crossing over occurs.
  • Metaphase I: Bivalents align randomly.
  • Anaphase I: Homologs separate to opposite poles.
  • Telophase I: Two haploid cells form.

  1. Meiosis II: Resembles mitosis; sister chromatids separate.
• What are the key structures and proteins involved in cell division?

  • Centrosome: Organizes spindle fibers.
  • Kinetochore: Attaches spindle fibers to chromosomes.
  • Motor Proteins: Kinesin and dynein move chromosomes.
  • Histones: Package DNA into chromatin.
• What are the applications and skills related to cell division?

  • Microscope Skills: Identify mitosis phases in micrographs.
  • Lab Examples:
  • Budding Yeast: Observe unequal cytokinesis.
  • DNA Extraction: Isolate DNA using detergent/enzymes.
• What is the summary of cell division processes?

  • Mitosis: Ensures genetic continuity.
  • Meiosis: Promotes genetic diversity.
  • Errors: Nondisjunction highlights precision needed in division.
  • Genetic Variation: Underpins evolutionary adaptation.