BIO130H1 Chapter Notes -Vacuole, Cell Membrane, Lysosome

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fuchsiamammoth394

7 Apr 2012

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BIO130H1 Full Course Notes

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Transport from the trans golgi network to lysosomes. Trans golgi network: sorts all the protein that passes through the golgi apparatus. Lysosomes are the principle sites of intracellular digestion. Lysosomes: membrane enclosed compartments filled with enzymes that control intracellular digestion. For optimal activity the enzymes are activated in an acidic environment (ph. Unique membrane structure highly glycosylated to protect it from lysosomal proteases. Atp pump can be used to acidify the lysosome: uses atp to create adp and. Lysosomes are formed by late endosomes with material from both the plasma membrane and newly synthesized hydrolases. Late endosomes form endolysomes after fusing with preexisting lysosomes. When the material in the endolysome is exocytosed then it forms the lysosome. They can then fuse again with endolysome again and the cycle can repeat itself. There is no real distinction between endolysome and endolysosome; they are just different stages within a cycle. Plant and fungal vacuoles are remarkably versatile lysosomes.

Related Questions

5 A) Which of the following statements about apical and basolateral protein sorting is FALSE?

Transcytosis is a mechanism for the movement of basolaterally secreted proteins to the apical membrane.

Infection of epithelial cells with specific viral proteins has helped elucidate the mechanisms of polarized protein secretion.

GPI-linked proteins are sorted specifically to the apical membrane of most polarized epithelial cells.

Vesicles that bud from the trans-Golgi network travel specifically to the apical membrane.

5 B) How does lysosomal pH contribute to lysosomal protein sorting?

Lysosomal proteins only properly fold at the acidic pH found in the lysosome.

Acidic pH is required for fusion of clathrin-coated vesicles with the lysosomal membrane.

Clathrin/AP1 vesicles that travel to the lysosome have a high affinity for lysosomal membranes due to their low pH.

The mannose-6-phosphate receptor has altered affinity for M6P under acidic pH conditions.

sapphireeagle929

lysosomes are cell organelles that contain enzymes such aslipase in an acidic environment. I want to test the effect of pH onthe activity of enzymes of enzymes extracted from the lysosomes andare provided with test solution with a pH of 3, 5, 7, 8, 10. atwhat pH do you expect the enzymes to be most active?