Metabolic diseases

Question 0

What is pyruvate kinase deficiency and which cell types does it occur in?

Answer 0

A lack of the enzyme pyruvate kinase in the last step of glycolysis. Because pyruvate is not created, the citric acid cycle function which leads to a lack of ATP production. This deficiency only occurs and erythrocytes.

Question 1

What is lactic acidosis? Name 3 causes?

Answer 1

Buildup of pyruvate. Which leads to lactate. Which leads to acidosis. Causes: intense exercise, impaired O2 delivery, impaired respiration, cyanide poisoning, alcohol, Pyruvate dehydrogenase deficiency, or anything that leads to build up of pyruvate.

Question 2

What are the two types of arsenic poisoning?

Answer 2

Arsenate and arsenite.

Question 3

How does arsenate affect the metabolic production of ATP?

Answer 3

Arsenic acts similar to phosphate. It binds to glyceraldehyde three phosphate during step six of glycolysis. This inhibits the production of ATP during step seven of glycolysis.

Question 4

How does arsenite affects metabolism?

Answer 4

It inhibits the pyruvate dehydrogenase complex. This leads to a lack of acetyl coA production. And a buildup of pyruvate.

Question 5

Where does cyanide poisoning effect the production of ATP?

Answer 5

Cyanide blocks the electron transport chain at cytochrome oxidase or complex IV of oxidative phosphorylation.

Question 6

Name two diseases that affect glycolysis?

Answer 6

Pyruvate kinase deficiency and arsenic poisoning.

Question 7

Name two diseases that affect citric acid cycle?

Answer 7

Pyruvate carboxylase deficiency and pyruvate dehydrogenase deficiency.

Question 8

What is pyruvate carboxylase deficiency? What intermediate does this affect? What pathways does this disease affects? What are the potential symptoms?

Answer 8

A loss of the pyruvate carboxylase enzyme effects production of oxaloacetate. Oxaloacetate is used in the citric acid cycle and gluconeogenesis. Pyruvate builds up which leads to a lack of ATP production. This also leads to lactic acidosis. A lack of gluconeogenesis leads to hypoglycemia.

Question 9

What is pyruvate dehydrogenase deficiency? What intermediate does this affect? What are the potential symptoms? What are the treatments?

Answer 9

A lack of the pyruvate dehydrogenase enzyme. This enzyme turns pyruvate to acetyl coA. This leads to lactic acidosis and potential neurological problems in the less severe form. The treatment is a high fat low carb diet and thiamine supplement

Question 10

What is the treatment for cyanide poisoning?

Answer 10

Nitrite is used to oxidized hemoglobin to methemoglobin which binds CN.

Question 11

Name three mitochondrial mutation diseases that affect oxidative phosphorylation? In general, what types of diseases present?

Answer 11

MERRF - Myoclonic epilepsy and ragged red fiber disease Lebers hereditary optic neuropathy Leigh syndrome All of these diseases lead to some type of neurological or neurodegenerative problems

Question 12

What is myoclonic epilepsy and Ragged red fiber disease? (MERRF) What are the symptoms of the disease? What are the treatments of the disease?

Answer 12

A point mutation in mitochondrial DNA that could encodes lysine in tRNA. Symptoms include epilepsy and dementia. Treatment none.

Question 13

What is Lebers hereditary optic neuropathy? What are the symptoms?

Answer 13

Mutation in complex one of oxidative phosphorylation. Blindness and young adults due to the degeneration of the optic nerve. The optic nerve requires a great deal of ATP.

Question 14

What is Leigh syndrome? What are the symptoms?

Answer 14

A mutation to complex one and four of oxidative phosphorylation. Effect central nervous system, movement disorders, breathing, and dystonia.

Question 15

Name some diseases that affect fatty acid oxidation?

Answer 15

MCAD deficiency Carnitine defects Jamaican vomiting sickness Propinoyl coA carboxylase deficiency Methylmalonyl mutase

Question 16

Name three peroxisomal associated disorders?

Answer 16

Zellweger syndrome Adrenoleukodystrophy Resum disease

Question 17

What is Jamaican vomiting sickness and what does it inhibit? What occurs in the body as a result?

Answer 17

Ingestion of hypoglycin toxin inhibits short and medium chain acyl-CoA dehydrogenases in the fatty acid oxidation pathway. Blood glucose levels fall fast, fatty acid levels rise.

Question 18

Name one carnitine defect? What does carnitine do In the fatty acid pathway? What are the potential treatments?

Answer 18

CPT II deficiency Carnitine allows for the transfer of fatty acids in and out of the mitochondrial matrix Avoid fasting lipid intake and excessive exercise

Question 19

What is MCAD deficiency? What are the potential treatments?

Answer 19

Defect in medium chain acyl-CoA dehydrogenase. Avoid fasting. Eat a high carb and a low-fat diet.

Question 20

What is propionyl coA carboxylase defect? What does this enzyme do and what are the potential consequences of losing its function? Name one Treatment.

Answer 20

One of four organic acidemias. Defect in enzyme that converts propionyl coA into methylmalonyl coA. Leads to build up of pripionate and acidemia. Symptoms include vomiting, protein intolerant, metabolic acidosis, lethargy, development delay, mental retardation, hypoglycemia. Treatment includes bicarbonate to correct acidosis.

Question 21

What is Zellweger syndrome and what does it affect? What are the symptoms?

Answer 21

Defect in peroxisomal biogenesis. mutation leads to cumulation of very long chain fatty acids in blood. Symptoms- hypotonia, facial dysmorpism, seizures, liver dysfunction.

Question 22

What is adrenoleukodystrophy?

Answer 22

Defect in ABCD1 gene. Leads to accumulation and damage to myelin sheath.

Question 23

What is resum disease? Symptoms? Treatment?

Answer 23

A defective alpha oxidation enzymes leads to accumulation of fatty acids. Symptoms include blindness, deafness, sensory neuropathy, cerebral ataxia. Dietary restrictions

Question 24

In general, what do the accumulation of very long chain fatty acids result in?

Answer 24

Myelin sheath damage

Question 25

Describe Zellwegers Syndrome?

Answer 25

A peroxisomal disorder where there are no peroxisomes. Without peroxisomes the body can not break down VLCFA. This leads to a build up of VLCFA i the blood.

Hyptonia, facial dysmorphoism, seizures, liver disfunction

Question 26

What is Adrenoleuckodystrophy?

Answer 26

Adrenoleuckodystrophy is a peroxisomal disorder that effects the transport of VLCFA into the peroxisome.

Damage to myelin sheath and motor disfunction

Question 27

What is Refsum Disease?

Answer 27

A peroxisomal disorder the effects the enzyme that breaks down phytanic acid ( a branched chain fatty acid).

Phytanic acids is found in dairy products and fats of ruminant animals.

Question 28

What is the role of peroxisomes in fatty acid metabolism

Answer 28

Peroxisomes break down Very long chain fatty acids and branched chain fatty acids. Once broken down these smaller fatty acids proceed to the mitochondria for beta oxidation.