This document discusses Tay-Sachs disease, a genetic disorder caused by a deficiency in an enzyme leading to the accumulation of fatty substances in the nervous system, ultimately resulting in severe neurological decline and early death. It explains the structure and functions of lysosomes, including their roles in digestion, recycling damaged organelles, and facilitating the breakdown of materials through phagocytosis. The relationship between Tay-Sachs disease and lysosomal function is highlighted, emphasizing the critical role of lysosomes in cellular maintenance and development.

1. TSD and the lysosome: maTrix edition Created by: Phagocytes, TJC CG 30/06 This presentation has been edited to reduce its file size. A Quick Note

2. Tay-Sachs Disease and the lysosome LEFT: Akari Yamada holds her son, Davis Jr., nicknamed DJ. He suffers from Tay-Sachs, a rare disease that has left him blind and taken away most of the skills he had as a baby . Daily Herald Photo/ Bill Zars Tay-Sachs Disease Lysosome

3. In This Presentation What is TSD? Genetically Speaking… e - Micrograph Functions About TSD (Tay-Sachs Disease) Structure About the Lysosome Structure-Function Among Organelles The Lysosome’s Relationships

4. Brain and nerve cells become damaged and gradually lose their ability to function properly. About TSD What is TSD? Genetic disorder caused by a deficient enzyme which results in the extreme accumulation of a fatty substance in the nervous system. No cure; death by about age 5 hex-A ganglioside GM2 Tay-Sachs Disease is… the lysosomes don’t contain a certain enzyme to break down a certain fat… a lysosomal storage disease! Fatty materials Normal brain cell Tay-Sachs brain cell 1) Development of mental and motor f(x) fails. 2) Nervous system is shut down.

5. About TSD Genetically Speaking… Autosomal recessive genetic condition Inherit from carrier parents Mutation on chr 15 in HEXA gene encoding hex-A From carrier parents: 1 in 4 chance

6. About the Lysosome URL ASF Structure Generally… what the lysosome is about TSD and the lysosome: maTrix edition Source: United Streaming Saved As: lysosomes (general) (unitedstreaming).asf The video clip has been removed to reduce file size.

7. About the Lysosome URL Structure This slide is derived from an animation: Cutting the lysosome… Outer membrane removed - easier to see contents Lumpy brown structures are hydrolytic (digestive) enzymes . Dissolving the membrane… Look at the enzymes . Some important enzymes: Lipases Carbohydrases Proteases Nucleases LYSOSOME Membrane-bound vesicle containing hydrolytic enzymes Lysosome Lysosomes can be known as “suicide sacks”. They are produced by the Golgi apparatus and consist of a single membrane surrounding powerful digestive enzymes . Partially permeable membrane pH 5 medium Hydrolytic enzymes

8. About the Lysosome e - Micrograph

9. About the Lysosome Digestion of materials from phagocytosis Lysosomes fuse with phagosomes to deliver hydrolytic enzymes for digestion. Autophagy (Autophagocytosis) Old or damaged organelles are broken down and recycled. Autolysis Self-digestion of a damaged cell. Can also be part of normal development (eg tadpole) Functions Digestion of materials from phagocytosis Lysosomes fuse with phagosomes to deliver hydrolytic enzymes for digestion. Autophagy (Autophagocytosis) Old or damaged organelles are broken down and recycled. 1/2 3

10. About the Lysosome Functions 1.Digestion of materials from phagocytosis 2.Autophagy (Autophagocytosis) URL ASF TSD and the lysosome: maTrix edition Source: United Streaming Saved As: lysosomes (phagocytosis) (unitedstreaming).asf The video clip has been removed to reduce file size.

11. About the Lysosome Functions 3.Autolysis Example with tadpole URL ASF TSD and the lysosome: maTrix edition Source: United Streaming Saved As: lysosomes (tadpole) (unitedstreaming).asf The video clip has been removed to reduce file size.

12. The Lysosome’s Relationships pH 5 medium - For enzyme activity - Cell safety Membrane: presence - Cell safety Membrane: partial permeability - Ensures complete hydrolysis Structure-Function Partially permeable membrane pH 5 medium Hydrolytic enzymes

13. The Lysosome’s Relationships Lysosome Formation Endoplasmic reticulum - Enzyme proteins made in rER - Transported to GA by vesicles Golgi apparatus - Create the hydrolytic enzymes - Produces lysosomes Among Organelles Next: Quick summary of lysosomes (Animation)

14. X Quick summary of lysosomes TSD and the lysosome: maTrix edition Source: McGraw-Hill Saved As: lysosomes (mcgraw-hill).swf The video clip has been removed to reduce file size.

15. Tay-Sachs Disease and the lysosome Thank you for your kind attention.