Cell Organelles Flashcards
The endoplasmic reticulum consists of what?
Cisternae
Tubules
Vesicles
What is the cytoplasm divided into by the ER.
The luminal or cisternae compartment
The cytoplasmic or cytoplasmic compartment
What types of cells have a lot of rough ER?
Cells that secrete protein.
(eg: Pancreatic exocrine cells v Liver Hepatocytes / 60 v 35)
Where does protein modification and assembly occur?
Where do these proteins go?
Rough ER
Some proteins are sorted for intracellular use and others for outside of the cell (collagen, cell membrane proteins)
How do ribosomes attach to the RER?
Under the guidance of the amino acid sequence, they are synthesizing. This is called the signal sequence.
What side of the Golgi Apparatus do proteins usually go in to?
The cis side.
What does the smooth ER do?
Glycogen metabolism
Lipid Synthesis
Phospholipid Synthesis
Detoxification
Steroidogenesis
Calcium regulation
What is the structure and purpose of the Golgi Apparatus?
Stacks of cisternae, which have a cis face facing the ER and trans face facing towards plasma membrane or nucleus
PTM of proteins and lipids, as well as trafficing
How much Nick Cage could a Nick Cage chuck if a Nick Cage could Nick Cage Nick Cage?
A Nick Cage amount of Nick Cages.
What does the smooth ER produce?
Polysaccharides & oligosaccharides
Sphingomyelin and glycosphingolipids
Also modifies carbs on glycoproteins and proteoglycans and provides post-translational changes.
What are lysosomal enzymes marked with in the Golgi apparatus?
Mannose-6-phosphate
In what way do materials in the Golgi Apparatus move?
Either way, retrograde or anterograde
What are those products moved to the lysosome from the Golgi Apparatus or membrane coated in?
What substance from the exterior is often brought to lysosomes?
Clatherin
Cholesterol
What do COP-coated vesicles direct themselves to?
COPII-coated vesicles?
COP I = Between Stacks and from GA to ER
COPII = From ER to GA
Describe endocytosis
Clathrin surrounds the receptors and adaptin to form a clatherin coated vesicle
Dynamin surrounds the neck of the coated pit, causing the vesicle to pinch off from the membrane.
What do lysosomes contain? How do they help the cell?
50-60 hydrolytic enzymes functional at acidic pH.
The monomeric subunits produced can escape into the cytoplasm through specific transporters and be reused.
How do primary lysosomes form?
In the GA lysosomal enzymes are phosphoralated with mannose-6-phosphate.
These bind to M6P receptor which cause the clatherin coated transport vehicle to be lost.
The enzymes are then stored in a primary lysosome
M6P receptors are returned to GA.
Differences in primary versus secondary lysosomes?
Primary - No digestive events, Homogenous, inactive enzymes
Secondary - Digestive enzymes, heterogeneous, active enzymes
What fuses to form the lysosome?
What is the hallmark of this event?
Fusion of transport vehicle and endosome
Lowering of pH to 5.5
What is the cause of Familial hypercholesterolmia?
Mutation in LDL receptor (incapable binding, binding at reduced capacity, incapable of internalization.)
Marked by elevation of LDL
Can cause atherosclerotic plaques
What is the function of peroxisomes?
synthesis and degradation of hydrogen peroxide
ß -oxidation of long-chain fatty acids
bile acid and cholesterol synthesis
detoxify alcohol
What are peroxisome disorders known as?
Zellweger spectrum disorders
The worst of which is Zellweger syndrome which is the absence or reduced number of peroxisomes in cells. Usually death within the first year of life.
How do high energy cells pack mitochondria versus others?
Much more packed, such as between myofibrils in high energy cells.
What causes the mitochondrial DNA diseases?
Mutations in the mt DNA that affect function (sometimes)
Also caused by mutations in the nuclear DNA which products may be imported into the mitochondria.
