考研资料北京大学细胞生物学第六章基质与内膜(上).ppt

Chapter 6
Cytoplasmic matrix, Endomembrane system, Protein Sorting and membrane trafficking
Learning objective
1. cells.
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Intracellular compartment % of total cell volume
Cytosol 54
Mittchondria 22
Rough ER cisternae 9
Smooth ER cisternae plus Golgi cisternae 6
Nucleus 6
Peroxisome 1
Lysosomes 1
Endosomes 1
Relative volumes occupied by the major intracellular compartments in Liver Cell
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C. The Dynamic Nature of the Endomembrane System
Most organelles are part of a dynamic system in which vesicles move between compartments.
Biosynthetic parthways move proteins, carbohydrates and lipids within the cell.
Secretory pathways discharge proteins from cells.
Endocytic parthways move materials into cells.
Sorting signals are recognized by receptors and target proteins to specific sites.
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D. A few approaches to the study of cytomembranes
Insights gained from autoradiography;
Insights gained from the biochemical analysis of subcellular fractions;
Insights gained from the study of genetic mutants;
The dynamic activities of endomembrane systems are highly conserved despite the structural diversity of different cell types.
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De Duve, and ,1974 Nobel Plrize
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2. The structure and functions of Endoplasmic
Reticulum(ER)
Rough endoplasmic reticulum and Smooth endoplasmic reticulum
RER has ribosomes on the cytosolic side of continuous, flattened sacs(cisternae); SER is an interconnecting network of tubular membran