1. BIOLOGY OF HUMAN AGING CHAPTER 3 CELLULAR AGING

2. Cell components * Organelles * Nucleus * Cytoplasm * Plasma membrane

3. Plasma Membrane Phospholipids Associated proteins & lipids Intercellular space

4. Fluid Mosaic Model Figure 3.3

5. Nucleus Nuclear membrane Contain genetic material Coded messages that direct synthesis of certain proteins DNA  RNA  Proteins DNA replication and transcription

6. From DNA to Protein Figure 3.34

7. Cytoplasm mRNA is being translated to protein rRNA and tRNA play a role in protein synthesis There are other important organelles within the cytoplasm –Endoplasmic rticulum –Ribosomes –Golgi Apparatus –Lysosomes –Mitochondria –Centrioles –Cytoskeleton

8. Structure of a Generalized Cell Figure 3.2

9. Validity of cell-culture findings Programmed series of events –Growing cells in culture (in vitro vs. in vivo) Cells are similar and intrinsic control factors Maintaining culture cells for a long time  observe  changes resembled senescent body cells Total # of divisions the cells undergo remains the same. Limited capacity and regulation of the cell Progeria Fibroblasts have shorter life span in culture media Changes is nuclear DNA sequences occur with aging possibility of failure of cellular mechanisms and repair enzymes

10. Specific Cellular Changes During Aging Membrane changes (problems in transporting materials permeability, Mitochondia, & Lysosome) Nuclear changes (problems in DNA synthesis, enzyme repair mechanism, condensing the DNA, manufacturing protein, and decrease in cell division

11. Cytoplasmic changes Dramatic increase in volume Decrease rate of DNA synthesis Gradual buildup of lipofuscin (age-pigment)

12. Ribosomal changes rRNA decreases with aging Decline in protein synthesis Decrease in the rate of elongation of the amino acid chains using ribosome

13. Mitochondrial changes Production of lipofuscin Apparent disorganization of the membrane Structural changes Decrease in number of mitochondria in postmitotic cells Decrease in energy and contribute to functional changes

14. Lysosomal changes Play an important role in intracellular digestion and breaking foreign substances With aging the action of the lysosomes is less efficient in older cells Accumulation of undigestible residues… Changes in membrane Changes in number Changes in activity of enzymes