The endomembrane system Flashcards
Vesicles are..
Small membrane sacs that transport substances in the cell out of the cell
6 components of the endomembrane systems
- nuclear envelope
- Endoplasmic reticulum (ER)
- Golgi apparatus
- lysomes
- Cell membrane
- The vesicles
what is endocytosis?
When a vesicle buds off the plasma membrane enclosing material outside of the cell in the cell.
what is exocytosis?
A vesicle fuses with the cell membrane bringing contents in the cell out of the cell
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The site of protein synthesis are
ribosomes
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ER
Produces and transports proteins and lipids in/out of the cell
Lipids that make up the cell membrane is produced there
Rough ER
- studded with ribosomes
- responsible for the production of transmembrane proteins
Smooth ER
- lacks ribosomes
- the site where fatty acids and phospholipids are produced
Lumen
The interior of ER
The role of the Golgi apparatus is …
-modifies and sorts proteins/lipids
- Acts as a sorting station for proteins telling them their final destination
- synthesizes carbohydrates
How does vesicles aid protein sorting?
they transport proteins from the ER to the Golgi appartus
What are lysomes? How does it work with the Golgi apparatus
- Lysosomes are vesicles that neighbor the Golgi and that degrade damage or unneeded macromolecules
- Golgi packs up macromolecules and delivers the enzymes that kill to the lysosomes
What effects the efficiency of lysosomes
Ph: Lysosomal enzymes cannot function at the PH level of the cell (7)
Where are two places ribosomes are produced?
- In the rough ER
- Free ribosomes in the cytosol
signal sequence
are proteins that are sorted after translation and contains an amino sequence
Nuclear localization signals are
signaling sequences for proteins that need to travel to the nucleus
Proteins produced by ribosomes in the cytosol
For free ribosomes in the cytosol…
No signal sequence: stays in the cytosol
Amino-terminal signal: To chloroplast and mitochondria
Internal signal : To the nucleus
Proteins produced on the rough ER end up
- in the lumen of the endomembrane
- Kicked out of the cell
- Turn into transmembrane cells
SRP( signal-recognization proteins) is a
RNA protein that recognizes a signal sequence in the cytosol.
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