Lecture 21: Nitrogen Metabolism Flashcards Preview

Year 1: 09. CPR Exam 2 > Lecture 21: Nitrogen Metabolism > Flashcards

Flashcards in Lecture 21: Nitrogen Metabolism Deck (14)
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1
Q

With Hartnup’s disease, what amino acids are not properly reabsorbed?

A

Nonpolar amino acids

-mostly tryptophan

2
Q

With cystinuria, what amino acids are not properly reabsorbed?

A

Dibasic amino acids (COAL)

  • Cystine
  • Ornithine
  • Arginine
  • Lysine
3
Q

In Hartnup’s disease and cystinuria, where do you find decreased reabsorption?

A

Intestinal Lumen

Kidneys

4
Q

What is tryptophan a precursor to?

A

Serotonin
Melatonin
Niacin

5
Q

Describe symptoms of Hartnup’s disease.

A

Pellagra-like skin lesions

Neurologic manifestations

6
Q

Which vitamin deficiency can produce symptoms similar to Hartnup’s disease?

A

Niacin

7
Q

Describe symptoms of cystinuria.

A

Precipitation of cystine –> renal, ureteral, and bladder stones
Hematuria
Flank pain
Renal colic

8
Q

Describe phenylketonuria.

A

Lack of phenylalanine hydroxylase to convert phenylalanine to tyrosine
-Impairment of brain function

9
Q

Describe non-classical PKU.

A

Defects in cofactor for phenylalanine hydroxylase (PAH)

10
Q

Describe alkaproteinuria.

A

Black urine disease

-lack of homogentisic acid

11
Q

Describe ammonia toxicity.

A

Excessive ammonia due to disorders in urea cycle or liver failure –> highly toxic to brain and CNS

  • disrupt pH balance
  • depletion of glutamate
12
Q

Describe gout.

A

High levels of uric acid in blood

  • due to diet rich in purines (meat, seafood, lentils) and alcohol
  • Acidemia stimulates reabsorption
13
Q

Describe hyperammonemia.

A

Defects in any of the enzymes associated with urea cycle

14
Q

What is the role of carbamoyl phosphate synthetase II?

A

First step of de novo pyrimidine synthesis