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Protein Secretion

Protein Secretion. Higher Biology. Rough Endoplasmic Reticulum (rough ER). System of flattened sacs and tubules Encrusted with ribosomes on the outer surface if their membranes Continuous with outer nuclear membrane Provides a large surface area for chemical reactions

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Protein Secretion

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  1. Protein Secretion Higher Biology

  2. Rough Endoplasmic Reticulum (rough ER) • System of flattened sacs and tubules • Encrusted with ribosomes on the outer surface if their membranes • Continuous with outer nuclear membrane • Provides a large surface area for chemical reactions • Pathway for transport of materials

  3. Golgi Apparatus • Group of flattened fluid-filled sacs • Vesicles containing newly synthesised protein pinched off from rough ER • Fuse with outermost sac of Golgi apparatus • Protein passed from sac to sac by means of vesicles • Golgi apparatus processes protein -e.g. adds a carbohydrate -form a glycoprotein

  4. Exocytosis • Vesicles containing finished product -mucus -digestive enzyme -hormone • Pinched off at end of Golgi apparatus • Vesicles move towards cell membrane and fuse with it • Contents of vesicle discharged to outside

  5. Protein Secretion • Golgi bodies especially numerous and active in secretory cells -gastric gland cells in stomach walls -mucus -pepsin -pancreas -insulin

  6. Elements in a protein • Carbon • Hydrogen • Oxgen • Nitrogen • (sulphur)

  7. Structure of a protein

  8. Quaternary structure of proteins • 3 different types -fibrous proteins -globular proteins -conjugated proteins

  9. Fibrous proteins • Several spiral-shaped polypeptide molecules • Linked in parallel by disulphide bridges • Proteinhas a rope-like structure

  10. Globular proteins • Several polypeptide chains • folded roughly into a spherical shape like a tangled ball of string • Enzymes are globular proteins • Also vital component in cell and sub-cellular membranes

  11. Hormones • Chemical messengers • Globular protein • Exert a specific effect on tissues

  12. Antibodies • Y-shaped globular proteins • Made by lymphocytes • Defend body against antigens

  13. Conjugated proteins • Globular protein associated with a non-protein chemical • Glycoprotein -protein and carbohydrate -mucus

  14. Haemoglobin • Oxygen-transporting pigment in blood • Conjugated protein -globular protein globin -haem (non-protein containing iron)

  15. This powerpoint was kindly donated to www.worldofteaching.com http://www.worldofteaching.com is home to over a thousand powerpoints submitted by teachers. This is a completely free site and requires no registration. Please visit and I hope it will help in your teaching.

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