DSA: Cell Organelles Flashcards
4 functions of the ER
- Protein synthesis
- Lipid synthesis
- Protein folding
- Storage of calcium
Golgi apparatus functions
Post translational changes on proteins and lipids, trafficking
% of pancreatic exocrine cell membrane that is rough ER
60%
% of liver hepatocyte membrane that is mitochondria inner membrane
32%
3 topological categories of cell
- Nucleus and cytosol
- communication through nuclear pore complex - Organelles in secretory and endocrine pathway
- ER, golgi, endosomes, lysosomes - Mitochondria
What two compartments does the ER divide the cytoplasm in to
Luminal or cistern always compartment
Cytoplasmic or cytosolic compartment
3 important functions of rough ER
- Proteins modification and assembly
- Segregation of proteins for intracellular use
- Export proteins from the cell
How do most proteins exit the rough ER and where do they go
In vesicles transported to the cis portion of the Golgi apparatus
5 functions of smooth ER
- Glycogen metabolism
- Lipid and phospholipid synthesis
- Detoxification
- Steroidogenesis
- Calcium regulation
5 functions of the Golgi apparatus
- Modification of carbohydrates attached to glycoproteins and proteoglycans
- Polysaccharide and oligosaccharide synthesis
- Synthesis of sphingomyelin and glycosphingolipids
- Sorting secretory products
- Packaging and storing secretory products into secretory granules or vesicles
When does the golgi disassemble and reassemble
Disassembles during mitosis/meiosis
Reassembles in interphase
Clathrate coated vesicles
Vesicles are coated in clathrin; these vesicles are seen in the exocytosis/secretory and endocytosis pathway
Transport products from:
Golgi apparatus —> lysosomes
products from the exterior of the cell —> lysosomes
COP-coated vesicles
Coat protein
Transport products:
Between stacks of the Golgi apparatus (COP 1)
ER —> Golgi apparatus (COP 2)
2 important steps in the lysosomal sorting pathway
- Phosphorylation of lysosomal enzymes
2. Binding of lysosomal enzymes to M6P receptor
Primary lysosome
Storage site of lysosomal hydrolases
- no digestive enzymes
- homogenous
- inactive enzymes
Secondary lysosomes
Engaged in a catalytic process
- digestive enzymes
- heterogenous
- active enzymes
Important step in endosome maturation
Lower internal pH to 5.5
Familial hypercholesterolemia
Mechanism of cholesterol uptake is disrupted; characterized by elevated LDL (predominant cholesterol transport protein in the plasma)
High levels of LDL lead to atherosclerotic plaques
4 functions of peroxisomes (micro bodies)
- Synthesis and degradation of H202
- Beta oxidation of long chain FA
- Bile acid and cholesterol synthesis
- Detoxify alcohol
Zellweger spectrum disorders
Peroxisome biogenesis disorders caused by defect in assembly of the peroxisome; normally causes death within first year of life
What type of cells typically would have lots of rough ER
Cell that make secreted proteins
Lysosomes contain enzymes that are most active when
- what do they do
At acidic pH
Break down proteins, carbs, lipids, nucleus acids
