考研资料北京大学细胞生物学第六章基质与内膜(上)演示课件

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B. Endomembrane System
❖Endomembrane System : The structural and functional relationship organelles including ER,Golgi complex, lysosome, endosomes, secretory vesicles.
❖Membranes divide the cytoplasm of eukaryotic cells into distinct compartments.
Three categories in eukaryotic cells:
(1) the endomembrane system: ER, Golgi complex, Lys., secretory vesicles.
(2) the cytosol. (3) mitochondria, chloroplasts, peroxisomes, and the nucleus.
❖Membrane-bound structures (organelles) are found in all eukaryotic cells.
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A. Cytoplasmic matrix (Cytosol) and B. Endomembrane System
❖Cytoplasmic matrix and its functions
➢Cytoplasmic Matrix: The region of fluid content of the cytoplasm outside of the membranous organelles. Aqueous solution of large and small molecules including filaments of cytoskeleton which act as organizer for some order.
The protein synthesis, degradation and modification.
Cells carefully monitor the amount of misfolded proteins. An accumulation of misfolded proteins in the cytosol triggers a heatshock response, which stimulates the transcription of genes encoding cytosolic chaperones that help to refold the proteins. 4
2. The structural and functional relationship among the ER, Golgi complexes, lysosomes and plasma membranes of eukaryotic cells;
3. The pathways of proteins targeting and sortinΒιβλιοθήκη Baidu, and its mechanisms;
➢The Cytosol is the site of protein synthesis and degradation or modification. It also performs most of the cell’s intermediary metabolism.
3
Functions of cytoplasmic matrix:
1
Endosomes
1
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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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❖Membrane-bound structures (organelles) are found in all eukaryotic cells.
Relative volumes occupied by the major intracellular compartments in Liver Cell
Chapter 6
Cytoplasmic matrix, Endomembrane system, Protein Sorting and membrane Ltreaafrfniicnkgionbgjective
1. Compartmentalization in Eukaryotic Cells;
Intracellular compartment volume
% of total cell
Cytosol
54
Mittchondria
22
Rough ER cisternae
9
Smooth ER cisternae plus Golgi cisternae
6
Nucleus
6
Peroxisome
1
Lysosomes
4. The ways of protein modifications and intracellular sites after they are synthesized;
1
5. Types of vesicle transport and their functions.
1. The Compartmentalization in Eukaryotic Cells