Peroxisomes

Question 1

Most common function of peroxisomes

Answer 1

Fatty acid degradation and reactive oxygen metabolism

Question 2

Which tissues have peroxisomes

Answer 2

All, most prominent in liver brain and kidney

Question 3

How many membranes are peroxisomes surrounded by?

Answer 3

One

Question 4

Do peroxisomes contain DNA?

Answer 4

No

Question 5

Biological function of peroxisomes

Answer 5

Long branches chain acid shortening (beta and alpha oxidation)
Esther lipid plasmalogen biosynthesis
Bile acid synthesis
Glyxoylate detoxification

Question 6

Why is long and brbanches chain fatty acid shortening important?

Answer 6

Removing molecules wholes build ip have toxic effects and metabolises some fatty acid based singalling molecules

Question 7

What happens when glyoxylate isn’t further metabolised?

Answer 7

Oxidises to oxalate which percipitates as a calcium salt resulting in rental failutre

Question 8

What is beta oxididation consisting of

Answer 8

Sequential remove of 2 carbon units as acetyl CoA

Question 9

Where does beta oxidation take place?

Answer 9

Peroxisomes and mitochondria

Question 10

What are the consquences of peroxisome malfunction

Answer 10

Peroxisome biogenesis disorder (Zellweger Syndrome) and single gene deficiency

Question 11

Steps of peroxisomal protein import

Answer 11

Peroxisomal protein is made in cytosol, binds to receptor PTS1
Receptor docks to protein complex on peroxisome membrane
Protein transported into peroxisome
Receptor recycled
Cycle repeats

Question 12

In ZS what is defective?

Answer 12

Receptor or components of docking/recycling complexes

Question 13

Range of names at the Zellweger Spectrum from most severe to least

Answer 13

Zellweger syndrome, Neonatal adrenoleukodystrophy, Infantile refsum disease

Question 14

Symptoms of RCDP?

Answer 14

Peroxisomes are present but proteins missing. Abnormalities of CNS, overt growth.

Question 15

Treatment of Zellweger Spectrum Diseases

Answer 15

Symptomatic treatment based on biochemical pathway

Question 16

What is X-ALD

Answer 16

Disorder of peroxisomal beta oxidation

Question 17

What gene does X-ALD affect?

Answer 17

ABCD1 gene

Question 18

What does ABDC1 gene encode?

Answer 18

Membrane protein (ALDP) which belongs to ATP binding cassette family

Question 19

How is X-ALD diagnosed?

Answer 19

Very long chain fatty acid accumulation

Question 20

Is there a strong correlation between casual mutation and clinical presentation of X-ALD?

Answer 20

No

Question 21

What are the most freuqnet presentations of X-ALD?

Answer 21

Childhood cerebral ALD and adrenomyeloneuropathy

Question 22

When does CCALD (childhood cerebral ALD) manifest

Answer 22

3-10 years

Question 23

When does adremyeloneuropathy manifest?

Answer 23

Late 20s

Question 24

Treatment of X-ALD

Answer 24

Adrenal hormone therapy
Fat restricted from diet
Bone marrow transplant
Gene therapy

Question 25

Single gene disorder PH1 stands for?

Answer 25

Primary hyperoxaluria type 1

Question 26

What is PH1 and what is it caused by?

Answer 26

Autosomal recessive condition caused by defects in alanine glyoxylate amino transferase

Question 27

Function of alanine glyxoylate amino transferase

Answer 27

Peroxisomal liver enzyme that converts glycoxylate to glycine

Question 28

What is a subset of PH1 caused by

Answer 28

P11L mutation can cause AGT mis-targeting

Question 29

Treatment and therapies of PH1

Answer 29

High doses of Vit. B6 to normalise oxalate levels
Avoid food w/ high levels of oxalate
Liver transplant
Kidney transplant

Question 30

In what species of pathogenic fungi are peroxisomes needed for pathogenicity

Answer 30

Rice blast fungus and anthracnose fungi