Proteins Flashcards
What are some factors that affect the set of proteins expressed by the cell?
- Metabolic activity of the cell
- Cellular stress
- The response to signaling molecules
- Disease vs healthy cells
Why is the proteome larger than the genome?
Because more than one protein can be produced from a single gene because of Alternative RNA splicing
What does the ER form?
A network of membrane tubules continuous with the nuclear membrane
What is the Golgi apparatus?
A series of flattened membrane discs
What are lysosomes?
Membrane-bound organelles containing a variety of hydrolases that digest proteins, lipids, nucleic acids and carbohydrates
What do vesicles transport?
Materials between membrane compartments
What is synthesized in the ER?
lipids and proteins
Where does the synthesis of all proteins benign?
Cytosolic Ribosomes
What is the difference between the rough ER and the smooth ER
The RER has ribosomes on its cytosolic face whilst the SER lacks ribosomes
What do transmembrane proteins carry?
A signal sequence, which halts translation and directs the ribosome synthesizing the protein to dock with the ER forming the RER.
What is a signal sequence?
A short stretch of amino acids at one end of the polypeptide that determines the eventual location of a protein in a cell
When translation occurs after docking with the RER where is the protein inserted?
The membrane of the ER
What happens to proteins once they are in the ER?
They are transported by vesicles that bud off from the ER and fuse with the Golgi apparatus
What do proteins undergo as they move through the Golgi apparatus?
Post- Translational modification
How do molecules move through the Golgi apparatus?
The molecules move through Golgi discs in vesicles that bud off from one disc and fuse to the next one in the stack. Enzymes catalyze the addition of of various sugars in multiple steps to form the carbohydrate.
