Cell Biology
Cells, microscopy, and cell division
Every living thing is made of cells. Animal cells have: nucleus (controls the cell), cytoplasm (where reactions happen), cell membrane (controls entry/exit). Plant cells have all of these PLUS: cell wall (cellulose support), vacuole (filled with cell sap), chloroplasts (for photosynthesis).
Microscopy: **Magnification** = Image size ÷ Actual size. Light microscopes: up to ×1500. Electron microscopes: up to ×2,000,000.
Mitosis produces 2 genetically identical daughter cells for growth and repair. Stages: Prophase → Metaphase → Anaphase → Telophase.
Stem cells are unspecialised cells that can differentiate into specific cell types. Embryonic stem cells can become any type (totipotent). Adult stem cells are more limited. Used to treat leukaemia via bone marrow transplants.
Key Points to Remember
- 1Animal and plant cell structures
- 2Microscopy and magnification
- 3Mitosis and cell cycle
- 4Stem cells and differentiation
Pakistan Example
Stem Cell Treatment at Shaukat Khanum Hospital, Lahore
Shaukat Khanum uses bone marrow transplants — adult stem cell therapy — to treat blood cancers. Doctors harvest stem cells from a donor and transplant them into the patient, where they differentiate into healthy blood cells. This saves hundreds of Pakistani lives every year.