FOM 2.2.1 Flashcards
How might peroxisomes be identified with EMR? If not present, the culture can be soaked with what to cause diaminobenzidene to precipitate?
Crystalline structure in middle of vesicle Hydrogen peroxide (H2O2)
What is broken down through beta-oxidation within the peroxisome?
VLCFA, very long chain fatty acids
During lipid ether synthesis in the peroxisome, what is produced? What is it used for?
Plasmalogen Plasmalogen is a precursor to the lipid membrane in the brain
When the peroxisome is adversely affect, the plasmalogen production is also adversely affected? What would you expect to be a main clinical manifestation?
delayed motor milestones, delayed brain events
What are the two transporters of the peroxisome? What signal do they recognize?
PEX5, PEX7 (co-mingled w/ 18 & 21) PTS1 (Specific, C terminal) PTS2 (less specific, N terminal) Peroxisome Transport Signal
What is the three AA sequence of PTS1
Ser-Lys-Leu
What do PPARs stand for and what is their purpose?
Peroxisome Proliferator-activated receptor. Purpose: increase the # of peroxisomes
What do PPARs stand for and what is their purpose?
Peroxisome Proliferator-activated receptor. Purpose: increase the # of peroxisomes
What is X-ALD? What mechanism is affected in this disorder?
X-linked adrenoleukodystrophy. The transport of VLCFA’s into peroxisome is adversely effected. This is a spectrum disorder, so the severity depends on the amount of distruption.
What are two ways to treat X-ALD?
Diet & Lorenzo’s Oil (which inhibits body’s prod of VLCFA’s)
Intermembrane space of the mitochondria has similar conditions to what?
Cytosol
When H+ ions travel down the gradient into the matrix of the mito through ATP synthase what occurs?
ATP synthase spins turning ADP + P into ATP
When H+ ions travel down the gradient into the matrix of the mito through ATP synthase what occurs?
ATP synthase spins turning ADP + P into ATP
Can ATP synthase work in both directions?
Yes, the lysosome uses the reverse function to lower its pH.
Does the mitochondria have its own DNA? Does it encode for all proteins found in the mitochondria?
It does have its own DNA, but some proteins are still made from nucleus’ DNA and shipped to the mito.
What makes the lysozyme so identifiable on an EMR slide?
Large membrane containing multiple vesicular things
Are lysosomes acidic or basic? What purpose does this serve?
Acidic. These conditions are optimal for the enzymatic reactions that occur inside.
When lysosome proteins are created, they pass through these on their way to fully mature lysosomes.
Endosomes
The lysosome uses ATPase as a….
Proton pump. To make the lumen acidic.
What is the lysosome-specific signal?
M6P (mannose-6-phosphate)
What is the lysosome-specific signal?
M6P (mannose-6-phosphate)
Where is the M6P signal attached to the protein? When does that protein encounter the M6P receptor?
Golgi apparatus trans Golgi apparatus
What is affected by I Cell Dz (Inclusion Cell Dz)? Why is this so severe (reduces life expectancy to 7 y/o)?
Defective GlnNac Phosphotransferase No enzymes are receiving the M6P signal, so none are being transported to the lysosome. Thus, nothing is being broken to down.
What is hepatomegaly?
very large liver
Explain this image and the two schools of thought in regards to the formation of peroxisomes.
A - Refers to the growth and division model in which PPs are released from the ER and fuse with existing peroxisomes that then divide and create more peroxisomes
B - Peroxisome maturation model in which PPs from the ER fuse with existing PPs and create mature peroxisomes.
Where is plasmologen used after it is synthesized in the peroxisome?
It is sent to oligodendrocytes in the CNS to create myelin
Explain this image and what it relates to
Peroxisome Proliferator activation receptor. Fatty acids bind to FABP setting of a chain of events that leads to activation of PPRE. production of many peroxisomes.
How does the mitochondria increase the internal surface area?
Crista create invaginations in the mitochondria inner membrane. This allows for a higher surface area.
What is the process by which proteins are tagged to make a lysosome?
Any enzyme that has a mannose 6 phosphate tag on it will bind to the receptor in the trans Golgi. It is then packaged into a vesicle which is directed to the early endosome. The early endosome is being acidified by the proton atp pump. In the lower pH the enzyme will no longer bind to the receptor and thus it comes off into the endosome lumen. The empty receptor is then packaged into a vesicle that ships the receptor back to the trans Golgi where it can bind more enzyme. Repeat.
