Test 2

Cell Biology

Homotypic Fusion Vs. Heterotypic Fusion

Homotypic – occurs between biochemically similar membranes (e.g., ER-derived vesicles forming vascular tubular clusters)

Heterotypic - occurs between biochemically different comportments (e.g, vesicle fusing with lysosome)

Vascular transport pathways

From the ER, COP 2 vesicles bud, uncoat, and then fuse together, forming a vesicular tubular structure. Motor proteins transport these clusters along microtubules to the cis-Golgi

ER resident proteins

A recovery passed away returns ER resident proteins that leave the ER by accident to maintain its functions (ER resident proteins must remain in the ER)

Two models: Cargo movement through Golgi

Cisternal maturation (model 1): From ER, vesicular tubular clusters form new cis cisternae near the ER. With more cisternae formed, existing cisternae mature more to the trans face. Cargo remains in the maturing cisterna not moving between stacks. mature sone breaks into transport carriers at the trans end

Vascular transport (model 2): the circular tubular clusters deliver cargo to the cis-golgi. The Golgi Cerni doesn't move while transport vesicles but off caring cargo from one sister to the next until trans face is reached. A