Mitosis and Meiosis Quiz Reviewer

Mitosis

• Mitosis produces two identical daughter cells necessary for growth, repair, and maintenance in multicellular organisms.
• Prophase: Chromatin condenses into visible chromosomes, each with two sister chromatids joined at a centromere; the nuclear envelope begins disintegration and spindle fibers form.
• Metaphase: Chromosomes align at the metaphase plate, with spindle fibers attached to the centromeres.
• Anaphase: Sister chromatids are pulled apart towards opposite poles of the cell by spindle fibers after centromeres split.
• Telophase: Chromatids reach poles, de-condense into chromatin, and the nuclear envelope reforms around two sets of chromosomes.
• Cytokinesis: Final step; cytoplasm splits into two distinct daughter cells. In animals, a cleavage furrow forms, while in plants, a cell plate forms.
• Outcome: Two genetically identical diploid daughter cells, maintaining the same chromosome number as the original cell.

Meiosis

• Meiosis results in four non-identical haploid daughter cells essential for sexual reproduction and genetic diversity.
• Consists of two successive divisions: Meiosis I and Meiosis II.

Meiosis I

• Prophase I: Chromosomes condense and become visible; homologous chromosomes pair (synapsis) forming tetrads, allowing for crossing over to increase genetic diversity.
• Metaphase I: Tetrads align at the metaphase plate; spindle fibers attach to centromeres of homologous chromosomes.
• Anaphase I: Homologous chromosomes are separated and move to opposite poles (sister chromatids remain attached).
• Telophase I: Chromosomes may reform nuclear envelope and undergo cytokinesis, resulting in two haploid cells.

Meiosis II

• Prophase II: Chromosomes condense again; nuclear envelope breaks down if reformed during Telophase I; spindle fibers reform.
• Metaphase II: Individual chromosomes align along the metaphase plate.
• Anaphase II: Centromeres divide, allowing sister chromatids to be separated and moved to opposite poles.
• Telophase II: Chromatids reach poles, nuclear envelope reforms, and cytokinesis produces four unique haploid cells.
• Outcome: Four genetically distinct haploid daughter cells with half the number of chromosomes as the original cell.

Body Tissues

• Body tissues comprise groups of similar cells working together to perform specific functions. Four primary types include:

Epithelial Tissue

• Function:
  • Protection against mechanical damage, pathogens, and dehydration.
  • Absorption of nutrients in organs like the intestines.
  • Secretion of hormones and enzymes in glands.
  • Excretion of waste products in kidneys.
• Types and Examples:
  • Simple Epithelium: Single cell layer (e.g., lining of the intestines).
  • Stratified Epithelium: Multiple cell layers (e.g., skin).
  • Cuboidal Epithelium: Cube-shaped cells (e.g., kidney tubules).
  • Columnar Epithelium: Tall, column-shaped cells (e.g., lining of the stomach).

Connective Tissue

• Function:
  • Provides support and structure to organs and tissues, helping maintain body shape.
  • Offers protection by cushioning organs and supporting the immune system.
  • Facilitates transport of nutrients and wastes within the body.

This quiz reviewer focuses on the processes of mitosis and meiosis, detailing their importance and stages. It highlights the key phases of mitosis, including prophase and the formation of daughter cells. Ideal for students studying cellular biology.