Cellular Structure pt 2 Flashcards
Lysosomes: recycling system of the cell
membrane enclosed organelles that consist of 50-60 hydrolytic enzymes most active at acidic pH:
capable of breaking down proteins, carbohydrates, lipids, and nucleic acids.
monomers escape through membrane and can be reused by cell
removes both material OUTSIDE the cell and obsolete components of the cell itself
morphologically diverse
Lysosomal Sorting Pathway: step 1
phosphorylation of lysosomal enzymes via mannose-6-phosphate
Lysosomal Sorting Pathway: step 2
binding of lysosomal enzyme to M6P receptor, followed by budding via clathrin coated pits
clathrin–adaptin–M6P receptor through membrane–M6P-L.Enzyme
Primary Lysosomes
enzymes inactive
storage site of lysosomal hydrolases
homogenous enzymes
Secondary Lysosomes
site of catalytic process
carries digestive enzymes
actively enzymatic
Pathways for intracellular degradation
- Receptor mediated endocytosis
- Autophagy
- Phagocytosis
Development of Lysosomes
Primary Lysosome buds from Golgi and fuses with an early endosome. Clathrin recycled.
Early endosome matures into Late endosome, secondary lysosome buds from late endosome
Lysosomes are formed from
fusion of transport vesicle with endosome
internal pH of late endosome =
5.5
Familial hypercholesterolemia
mechanism of cholesterol uptake is disrupted
elevation of LDL, the predominant cholesterol transport protein in plasma
Primary defect of hypercholesterolemia
defect in LDL receptor
Peroxisomes, also called
microbodies
Peroxisomes are a diverse group of organelles. They contain enzymes that ______ and which in turn can be broken down by ______
produce hydrogen peroxide
H2O2 is then broken down by catalase
function of the microbody (peroxisome)
hydrogen peroxide production
beta oxidation of long chain fatty acids
bile and cholesterol synthesis
detoxify alcohol
what do we “often” find in the core of the peroxisome
“urate oxidase” crystalline core
