Lesson #6

Question 1

True or false: The mitochondria have around 90 proteins within it, for various usages. The majority of the proteins are encoded for by mtDNA, while a small portion is encoded for by nDNA.

Answer 1

FALSE - The majority of proteins used in the mitochondria, are encoded for by nuclear DNA.

Question 2

If the ETC is dysfunctional, what would occur?

Answer 2

There would be a build-up of free radicals, which will damage mtDNA, and further disable the ETC - Eventually causing necrosis and apoptosis.

Question 3

Leber congenital amaurosis (LCA) -

Answer 3

The most severe mitochondrial disorder, causing retinal dystrophy. Encoded for by nDNA.

Question 4

Leber hereditary optic neuropathy (LHON) -

Answer 4

Progressive deterioration of the optic nerve. This is the most common mtDNA disorder.

Question 5

Kearns-Sayre Syndrome -

Answer 5

Degeneration of retinal pigments, weakness of occular muscles, cardiac conductance defect.

Encoded by mtDNA.

Question 6

How are mitochondrial disorders passed down thru generations?

Answer 6

Mitochondrial disorders are passed down by the mother, but affect all offspring. - Maternal inheritance pattern.

Question 7

Mitochondrial disorders effect most organ tissues. Which of the following would be most severely affected?

a. Skeletal muscle.
b. Liver and kidneys.
c. Ocular.
d. Skeletal bones.

Answer 7

A - Skeletal muscles.

Skeletal muscle, cardiac muscle, and brain tissues utilize the most energy, and therefore will be more severely affected by a dysfunction of the mitochondria.

Question 8

What histological feature is unique to mitochondrial disorders?

Answer 8

Ragged red fibers (RRF’s) - enlarged myofibers.

Question 9

Function of the smooth ER:

Answer 9

Lipid and glycogen metabolism, Ca++ storage, and detoxification.

Question 10

What protein will catalyze many reactions in drug metabolism and synthesis of cholesterol, steroids, and other lipids?

Answer 10

Cytochrome P450 Proteins.

Question 11

__________: Caused by alcohol and barbiturates - causes SER hyperplasia + increased detoxification. Causes a lower-than-expected concentration of therapeutic drugs.

Answer 11

Induction.

Question 12

__________: Caused by proton receptor blockers + histamine blockers + macrolides. Decreases drug detoxification, causing higher than-expected therapeutic drug levels.

Answer 12

Inhibition.

Question 13

Cytochrome P450 proteins are encoded for by what genes? Which specific one is responsible for 43% of cytochrome P450 proteins?

Answer 13

1. CYP genes.
2. CPY3A4.

Question 14

True or false: A patient who is taking a pharmecutical drug that’s main function is by utilizing CYP3A4 enzyme, has just drank a large glass of grapefruit juice - The patient will soon find that their medication is not working and their symptoms to reappear.

Answer 14

True - Grapefruit is an inhibitor of CYP3A4.

Question 15

Some CYP enzymes will increase metabolism, how will this affect the patient’s response to medication?

Answer 15

The patient will be at risk for being undertreated, cause their body will require more medication to be sufficient.

Question 16

What enzyme places markers on proteins so that they can later be recognized and destroyed by lysosomes? Where are these found?

Answer 16

1. phosphotransferase.
2. Golgi apparatus.

Question 17

_______ are formed due to dysfunctional phosphotransferase, causing lysosomes not to work. These cause fatal in childhood.

Answer 17

I-cell or Inclusion cells.

Question 18

In what conditions, do we see fragmented Golgi apparatus?

Answer 18

1. Alzheimer’s.
2. Lou Gehrigs.
3. Creuztfeldt jacob disease.

Question 19

Primary lysosome:

Answer 19

1. Buds off from golgi apparatus.
2. Contains lytic enzymes.

Question 20

Secondary lysosome:

Answer 20

1. Site of digestion.
2. Heterophagosomes - Do digestion of material from outside the cell.
3. Autophagosomes - Do digestion of the cell and cellular content.

Question 21

Post-digestive secondary lysosome:

Answer 21

1. Residual bodies.
2. Has lipofuschin granules that are called “wear and tear” pigment.
3. Seen more in older people.

Question 22

Which lysosomal disease causes an enlarged liver and heart, due to a deficiency of 1,4-glucosidase enzyme?

Answer 22

Pompe’s Disease.

Question 23

Which lysosomal disease causes deformity of the CNS and skeletal system, resulting in gargoylism - Due to a deficiency of L-Iduronidase?

Answer 23

Hunter and Hurler Syndromes.

Question 24

Tay-Sachs disease (lysosomal) causes gangliosidosis from deficiency of ___________ enzyme. It will affect the brain and eyes, and is fatal in childhood. There will will a build-up of _____________, and a lack of ______________

Answer 24

1. Hexosaminidase.
2. Build-up of gangliosides
3. Lack of cerebrosides.

Question 25

Which lysosomal disease will cause an enlarged spleen and anemia, caused by a deficiency of glucocerebrosidase enzyme.

Answer 25

Gaucher Disease.

Question 26

Explain the difference between Niemann pick type A/B and type C.

Answer 26

1. Niemann pick type A and B will have a deficiency of sphingomyelinase. While type C does not.

Question 27

What is the function of the peroxisome:

Answer 27

1. Oxidative enzymatic breakdown of toxins and organic compounds.

Question 28

__________ is the enzyme used for the breakdown of hydrogen peroxide to H2O and O2. Can oxidize alcohol in the liver and kidney.

Answer 28

Catalase.

Question 29

True or false: Oxidation of fatty acids will occur in the peroxisome, only when the fatty acid is too long to be processed by the mitochondria.

Answer 29

True.

Question 30

How much of the bodies phospholipids are made up of plasmalogens? How much of the white matter?

Answer 30

1. 20% of all phospholipids in the body are plasmalogens.
2. Greater than 80% of all phospholipids in the white matter are plasmalogens.

Question 31

Plasmalogens are a unique class of ____________________.

Answer 31

Glycerophospholipids.

Question 32

Rhizomelic chrondroplaysia punctata follows what inheritance pattern?

Answer 32

Autosomal recessive.

Question 33

Rhizomelic chrondroplaysia punctata type 1 is caused by:

Answer 33

A mutation in the PEX7 gene.

Question 34

Neimann Pick Type C is associated with:

Answer 34

Cholesterol lipodosis.

Question 35

Rhizomelic chrondroplaysia punctata type 2/3 is caused by:

Answer 35

Deficiency of peroxisomal enzymes involved in plasmalogen metabolism and synthesis.

Question 36

What is the most severe peroxisome biogenesis disorder?

Answer 36

Zellweger syndrome.

Question 37

What happens to peroxisomes during Zellweger syndrome?

Answer 37

Peroxisomes will have a large reduction, or become completely absent in the liver, kidney, and brain specifically.

Question 38

Which mutation causes Zellweger syndrome?

Answer 38

Mutation in PEXR1 - Required for transport of peroxisome targeted enzymes.

Question 39

Which leukodystrophy has manifestations of progressive demyelination and dysfunction of the adrenal cortex?

Answer 39

Adrenoleukodystrophy.

Question 40

What inheritance pattern does adrenoleukodystrophy follow?

Answer 40

X-linked recessive.

Question 41

What inheritance pattern does Zellweger Syndrome follow?

Answer 41

Autosomal recessive.

Question 42

Mutation in the ABCD1 gene will impair transport of VLCFA’s, and cause what kind of leukodystrophy?

Answer 42

Adrenoleukodystrophy.