PAG Extended Questions | Latest Version | 2024/2025 | Verified Solutions

PAG Extended Questions | Latest Version | 2024/2025 | Verified Solutions **What is the purpose of mitosis for a living organism?** Mitosis serves for growth and repair of tissues, as well as for asexual reproduction. **What distinguishes each stage of mitosis?** Prophase: Chromosomes become visible. Metaphase: Chromosomes align along the center of the cell. Anaphase: Chromatids separate and move towards opposite poles. Telophase: Two nuclei become visible as the cell prepares to split. **Why is it incorrect to say that cells in interphase are "resting"?** Interphase is active with processes like DNA checking, protein synthesis, respiration, and mRNA synthesis occurring. **Why is a sample from the roots of Allium spp. ideal for studying mitosis?** Root cells are actively dividing, making it easy to find cells in various stages of mitosis. **In your Allium spp. specimen, which stage of the cell cycle do most cells appear to be in, and why?** Most cells appear to be in interphase because it's the longest phase where cells prepare for division. **Could you use your own blood for this practical? What precautions would you take?** Yes, students could use their own blood, taking precautions like pre- and post-swabbing with ethanol, covering with sterile dressing, and ensuring personal handling and disposal of materials. **Estimate the concentration of erythrocytes in a blood sample. What facts are needed, and what is the uncertainty in this estimate?** An estimate of 5 billion erythrocytes per cm3 seems reasonable. Accurate measurement would require a haemocytometer and serial dilution due to high concentration. **Using the diameter of a typical erythrocyte, estimate its volume assuming it is spherical. Is this likely an over- or under-estimate?** Assuming a 7 μm diameter, the spherical volume would be 180 μm3 or 1.8 x 10-16 m3. Erythrocytes are biconcave, so this is likely an overestimate. **What are the functions of the different cell types in your blood sample?** Erythrocytes carry oxygen and carbon dioxide. Thrombocytes aid in blood clotting. Lymphocytes provide specific immunity. Neutrophils engage in non-specific immunity. Eosinophils respond to inflammation and parasites. Basophils contribute to inflammatory responses. **Based on your observations,