Genetics Unit 26: Peroxisomes

Front 1

5 Biochemical reactions of peroxisomes listed in book

Back 1

1) Catalyzes first 2 steps in plasmalogen synthesis
2) Beta oxidation of FAs especially VLCA which mitochondria cant oxidize well.
3) Converting O2 into H2O2
4) Oxidation of bile acid precursors in the last step of bile acid synthesis.
5) Alpha hydroxylation of a 20C derivative of phytanic acid

Front 2

Plasmalogens

Back 2

Are ether glycolipids. Are 5-20% of phospholipids in most mammalian cells but 80-90% of phospholipids in myelin.First 2 steps of synthesis occur in peroxisomes.

Front 3

What is the purpose of peroxisome beta oxidation

Back 3

1) Supply acetyl-coa for anabolid reactions like cholesterol synth and acetylation.
2) Catabolize substances which are poorly oxidized by mitochondria including VLCFAs, long chain di carboxylic acids, and the side chains of cholesterol

Front 4

3 Disorders of the zellweger spectrum and cause of these disorders

Back 4

Zellweger syndrome, neonatal adrenoleukodystrophy, and infantile refsum disease. All disorders involve mislocation of peroxisomal proteins.

Front 5

Adrenoleukodystrophy (ALD)

Back 5

Most common peroxisomal single enzyme defect. Is X linked. Leads to impaired degredation of VLCFAs. Causes demylenation leading to motor problems, sleep problems, and general mental problems.

Front 6

What type of fatty acids do peroxisomes beta oxidase? Do they oxidize them to acetyl coa?

Back 6

Is at maximum activity for C12-16, can do C24, and unsaturated are better utilized than saturated.
Peroxisomes do not catabolize FAs to acetyl coa because oxidation dosent go beyond C6.

Front 7

RCPD

Back 7

Caused by deficiency in PTS-2, the PEX7 product. Despite other problems, does not cause problem with VLCFA breakdown. Unlike other zellweger syndromes, it also does not cause problems with neuronal migration. Therefore, neuronal migration is due to a buildup or the improper breakdown of VLCFAs.