Gen Zoology Pointers for Final Exam PDF

Gen Zoology Pointers for Final Exam Cell Division and Genetics A sperm cell is haploid, containing 22 autosomes and either an X or Y chromosome. An egg cell is haploid too but only X chromosomes Movement of Homologous Chromosomes:In meiosis I, homologous chromosomes (chr...

Gen Zoology Pointers for Final Exam Cell Division and Genetics A sperm cell is haploid, containing 22 autosomes and either an X or Y chromosome. An egg cell is haploid too but only X chromosomes Movement of Homologous Chromosomes:In meiosis I, homologous chromosomes (chromosome pairs) separate and move toward opposite poles. Similarity between Meiosis II and Mitosis: Both meiosis II and mitosis involve the separation of sister chromatids during anaphase. Cell Plate Development in Cytokinesis: In plant cells, the cell plate forms during cytokinesis to divide the cell. In animal cells, the cleavage furrow is formed. MPF activity declines at the end of mitosis: The cyclin component of MPF is degraded at the end of mitosis, leading to the decline in MPF activity. Effect of Cytochalasin B on Cell Cycle: Cytochalasin B disrupts actin function, affecting cleavage furrow formation during cytokinesis. Tissues and Organ Systems Epithelial tissue forms protective layers that line organs and body cavities. Adipose tissue is connective tissue that stores fat, which serves for insulation and energy storage. Collagenous fibers provide strength and flexibility to connective tissues. Nervous tissue is not a type of connective tissue; it consists of neurons and glial cells. Muscle tissue contracts when stimulated by nerve signals, allowing movement. Smooth muscle is responsible for involuntary movements like those of internal organs. Neurons are specialized cells responsible for transmitting electrical signals in the nervous system. An osteon is the fundamental structural unit of compact bone tissue. Squamous epithelial cells are flat and resemble floor tiles, suited for diffusion and protection. Key Terms to Remember: Autosomes: Non-sex chromosomes. Homologous Chromosomes: Chromosome pairs, one from each parent, that are similar in shape and size. Cytokinesis: The process where the cytoplasm of a parent cell divides into two daughter cells. MPF (Maturation-Promoting Factor): A complex involved in the regulation of the cell cycle. Cleavage Furrow: The indentation that forms during cytokinesis in animal cells, helping to divide the cytoplasm. Collagenous Fibers: Fibers in connective tissue providing structural strength. Osteon: A cylindrical structure in bone tissue that contains the central canal for blood vessels and nerves. II. Review the phases of cell division This illustration depicts the key phases of the cell cycle and the corresponding movement or fate of chromosomes: In interphase, chromosomes exist as uncondensed chromatin within the nuclear envelope. DNA replication occurs in preparation for mitosis, producing sister chromatids. In Prophase, chromatin condenses into distinct chromosomes, each composed of two sister chromatids joined at the centromere. The nuclear envelope begins to break down. In Prometaphase, microtubules from the mitotic spindle attach to kinetochores at the centromeres, facilitating chromosome alignment. In Metaphase, chromosomes align at the metaphase plate (equatorial plane), ensuring each sister chromatid is oriented toward opposite poles. In Anaphase, sister chromatids separate as microtubules pull them toward opposite poles of the cell. Each chromatid becomes an individual chromosome. Finally, when the cell is in Telophase and Cytokinesis, chromosomes reach the poles and decondense back into chromatin. The nuclear envelope reforms around each set of chromosomes, resulting in two genetically identical nuclei. Finally, the cell divides through cytokinesis, producing two daughter cells. Molecular mechanisms that help regulate the cell cycle. The human life cycle. In each generation, the number of chromosome sets is halved during meiosis but doubles at fertilization. For humans, the number of chromosomes in a haploid cell is 23, consisting of one set (n = 23); the number of chromosomes in the diploid zygote and all somatic cells arising from it is 46, consisting of two sets (2n = 46). 1. Cuboidal Epithelium: Composed of cube-shaped cells, it is found in glands and kidney tubules. It functions in secretion and absorption. 2. Simple Columnar Epithelium: Made of tall, column-like cells, it lines the digestive tract and is specialized for absorption and secretion. 3. Pseudostratified Ciliated Columnar Epithelium: Appears layered but is not; all cells touch the basement membrane. Found in the respiratory tract, its cilia help move mucus and trapped particles. 4. Stratified Squamous Epithelium: Multiple layers of flat cells provide protection against abrasion. Found in the skin, mouth, and esophagus. 5. Simple Squamous Epithelium: Single layer of flat cells, allowing for diffusion and filtration. Found in the lungs, blood vessels, and kidney glomeruli.