Urea Cycle

Question 1

Regulation

Answer 1

The liver has a vast capacity to convert AAs to urea. Ammonia is fatal if built up and not converted. Arginine and Glutamate are important factors in this cycle.

Question 2

Arginine

Answer 2

Main amino acid in the urea cycle production. The carbons from AA are important for making glucose through gluconeogenesis and the NH3 thats produced needs to be eliminated. The cycle starts in the mitochondria (1/2) and ends in the cytosol

Question 3

Totals

Answer 3

Four high energy phosphates are consumed in the synthesis of each molecule of urea. 2 ATP are needed to restore 2 ADP to 2 ATP plus 2 to restore AMP to ATP

Question 4

Phenylketonuria

Answer 4

conversion of Phe to Tyr is defective. Phenyalanine accumulates and is converted to compounds such as phenylketones (developmental delay) which gives the urine a musty odor. Mental retardation occurs.

Question 5

Alcaptornuria

Answer 5

Very rare disease that is a product of Phe and Tyr metabolism. Homogentistic acid autooxidizes and forms dark colored pigments that accumulate in tissues. This leads to degenerative arthritits.

Question 6

Parkinsons Disease

Answer 6

dopamine levels are decreased due to the deficiency in conversion of Dopa. This is shown by tremors, initiating voluntary movements, starting expression, shuffling gait.

Question 7

Albinism

Answer 7

tyronsinase is defective and Tyr cant be converted to skin pigment melanin. Characteristics include light colored skin, hair and eyes.