ER and secretory pathway Flashcards
Why do specialised cells have a lot of rough endoplasmic reticulum? [1 mark]
In order to secrete proteins
What is the structure of the endoplasmic reticulum? [1 mark]
Continuous network of membrane tubules
What is the endoplasmic reticulum involved in? [6 marks]
- Lipid/protein synthesis
- Glycosylation
- Folding of proteins
- Assembly of multi-protein complexes
- Ca2+ sequestration
- Detoxification (in liver)
What type of amino acid residues does the signal peptide have? [1 mark]
Lots of hydrophobic ones
What does the signal recognition particle (SRP) do? [2 marks]
- Interacts with the signal peptide
- Guides the ribosome to the translocon on the ER membrane
Do cytoplasmic proteins have disulphide bonds? [1 mark]
NO
Intermediates of insulin activation via proteolysis [3 marks]
Preproinsulin - proinsulin - insulin
What are the protein modifications in the ER? [5 marks]
- Proteolysis
- Disulphide bond formation
- Glycosylation
- Deglycosylation
- Protein folding and assembly
What is the cis side of the Golgi apparatus? [1 mark]
Where vesicles come to
What is the trans side of the Golgi apparatus? [1 mark]
Where vesicles leave
Roles of the Golgi apparatus [3 marks]
- Protein modification
- Lipid synthesis
- Protein & lipid sorting
