FOM 2.2.1

Question 1

How might peroxisomes be identified with EMR? If not present, the culture can be soaked with what to cause diaminobenzidene to precipitate?

Answer 1

Crystalline structure in middle of vesicle Hydrogen peroxide (H2O2)

Question 2

What is broken down through beta-oxidation within the peroxisome?

Answer 2

VLCFA, very long chain fatty acids

Question 3

During lipid ether synthesis in the peroxisome, what is produced? What is it used for?

Answer 3

Plasmalogen Plasmalogen is a precursor to the lipid membrane in the brain

Question 4

When the peroxisome is adversely affect, the plasmalogen production is also adversely affected? What would you expect to be a main clinical manifestation?

Answer 4

delayed motor milestones, delayed brain events

Question 5

What are the two transporters of the peroxisome? What signal do they recognize?

Answer 5

PEX5, PEX7 (co-mingled w/ 18 & 21) PTS1 (Specific, C terminal) PTS2 (less specific, N terminal) Peroxisome Transport Signal

Question 6

What is the three AA sequence of PTS1

Answer 6

Ser-Lys-Leu

Question 7

What do PPARs stand for and what is their purpose?

Answer 7

Peroxisome Proliferator-activated receptor. Purpose: increase the # of peroxisomes

Question 9

What do PPARs stand for and what is their purpose?

Answer 9

Peroxisome Proliferator-activated receptor. Purpose: increase the # of peroxisomes

Question 10

What is X-ALD? What mechanism is affected in this disorder?

Answer 10

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.

Question 11

What are two ways to treat X-ALD?

Answer 11

Diet & Lorenzo’s Oil (which inhibits body’s prod of VLCFA’s)

Question 12

Intermembrane space of the mitochondria has similar conditions to what?

Answer 12

Cytosol

Question 13

When H+ ions travel down the gradient into the matrix of the mito through ATP synthase what occurs?

Answer 13

ATP synthase spins turning ADP + P into ATP

Question 14

When H+ ions travel down the gradient into the matrix of the mito through ATP synthase what occurs?

Answer 14

ATP synthase spins turning ADP + P into ATP

Question 15

Can ATP synthase work in both directions?

Answer 15

Yes, the lysosome uses the reverse function to lower its pH.

Question 16

Does the mitochondria have its own DNA? Does it encode for all proteins found in the mitochondria?

Answer 16

It does have its own DNA, but some proteins are still made from nucleus’ DNA and shipped to the mito.

Question 17

What makes the lysozyme so identifiable on an EMR slide?

Answer 17

Large membrane containing multiple vesicular things

Question 18

Are lysosomes acidic or basic? What purpose does this serve?

Answer 18

Acidic. These conditions are optimal for the enzymatic reactions that occur inside.

Question 19

When lysosome proteins are created, they pass through these on their way to fully mature lysosomes.

Answer 19

Endosomes

Question 20

The lysosome uses ATPase as a….

Answer 20

Proton pump. To make the lumen acidic.

Question 21

What is the lysosome-specific signal?

Answer 21

M6P (mannose-6-phosphate)

Question 22

What is the lysosome-specific signal?

Answer 22

M6P (mannose-6-phosphate)

Question 23

Where is the M6P signal attached to the protein? When does that protein encounter the M6P receptor?

Answer 23

Golgi apparatus trans Golgi apparatus

Question 24

What is affected by I Cell Dz (Inclusion Cell Dz)? Why is this so severe (reduces life expectancy to 7 y/o)?

Answer 24

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.

Question 25

What is hepatomegaly?

Answer 25

very large liver

Question 26

Explain this image and the two schools of thought in regards to the formation of peroxisomes.

Answer 26

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.

Question 27

Where is plasmologen used after it is synthesized in the peroxisome?

Answer 27

It is sent to oligodendrocytes in the CNS to create myelin

Question 28

Explain this image and what it relates to

Answer 28

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.

Question 29

How does the mitochondria increase the internal surface area?

Answer 29

Crista create invaginations in the mitochondria inner membrane. This allows for a higher surface area.

Question 30

What is the process by which proteins are tagged to make a lysosome?

Answer 30

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.