endomembrane system Flashcards
endomembrane system definition
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The endomembrane system is composed of the different membranes that are suspended in the cytoplasm within a eukaryotic cell. These membranes divide the cell into functional and structural compartments, or organelles.
organelles of the endomembrane system
nucleus, golgi, lysosomes, endosomal compartment, transport vesicles and peroxisomes
all compartments of the endomembrane system are connected by
transport vesicles that serve material exchange such as lipids and proteins
3 types of trafficking pathways
- secretory pathway (biosynthesis)
- endocytic pathway
- retrieval recycling pathway
transport vesicle
carry various ‘cargo e.g. synaptic vesicles
synaptic vesicles
50 types of integral proteins
7000 phospholipids
5700 cholesterol moelcules
molecular motors
move transport vesicles and organelles within the cell–> this process is called membrane trafficking.
how can secretory vesicle trafficking be visualised using
GFP- fusion proteins
vesicles mediate
exchange of material between the cell and the environment
exocytosis
release of material from a cell to the outside of the cell
endocytosis
material taken into a vesicle by the cell
secretory pathway
secretory pathway refers to the endoplasmic reticulum, Golgi apparatus and the vesicles that travel in between them as well as the cell membrane and lysosomes. It’s named ‘secretory’ for being the pathway by which the cell secretes proteins into the extracellular environment.
endocytic pathway
process in which cell takes in materials from the outside by engulfing and fusing them with its plasma membrane. Supplement. Most of the extracellular materials that the cells absorb are large polar molecules (e.g. proteins and hormones) that cannot pass through the hydrophobic plasma membrane by simple diffusion.
retrieval (recycling) pathway
how materials in cells get reused e.g. broken down in vesicles but then taken back to the ER to be packaged
