Disorders of Amino Acid Metabolism and Urea Cycle

These flashcards cover key concepts and terms related to disorders of amino acid metabolism and the urea cycle, based on the provided lecture notes.

Essential Amino Acids

Amino acids that cannot be synthesized by the body and must be obtained from the diet.

Nonessential Amino Acids

Amino acids that can be synthesized by the body and are not required in the diet.

Glucogenic Amino Acids

Amino acids whose carbon skeletons can be converted to glucose precursors.

Ketogenic Amino Acids

Amino acids that can be converted to acetyl CoA or acetoacetate.

TCA Cycle

Krebs cycle, a series of chemical reactions used by all aerobic organisms to generate energy through the oxidation of acetate.

Cystinosis

A metabolic disease characterized by the accumulation of cystine in various organs due to a defective transport mechanism.

Phenylketonuria (PKU)

A genetic disorder caused by a deficiency in phenylalanine hydroxylase leading to high levels of phenylalanine.

Urea Cycle

A series of chemical reactions in the liver that convert ammonia and carbon dioxide to urea.

Transamination

The process by which an amino group is transferred from one amino acid to a keto acid.

Hyperammonemia

A condition characterized by elevated levels of ammonia in the blood.

Arginine

An amino acid involved in the urea cycle and important for protein synthesis and metabolic functions.

Alanine

An amino acid that plays a critical role in glucose-alanine cycle, involved in nitrogen transport.

Oxaloacetate

A four-carbon molecule that plays a crucial role in the TCA cycle and is involved in amino acid synthesis.

Glutamate

An amino acid that serves as a precursor for other amino acids and is a key neurotransmitter.

Homocystinuria

An inherited disorder related to the metabolism of methionine, leading to the accumulation of homocysteine.

Citrulline

An amino acid that is produced in the urea cycle and serves as a precursor for arginine.

Nitrogen Balance

The difference between nitrogen intake and nitrogen excretion.

Disulfide Bonds

Chemical bonds formed between the sulfur atoms of two cysteine residues, which stabilize protein structure.

Alpha-Ketoglutarate

A five-carbon molecule that is a key intermediate in the TCA cycle and also serves as a precursor for several amino acids.

Synthesis of Non-Essential Amino Acids

The process of forming non-essential amino acids from metabolic precursors derived from glucose.

Asparagine Metabolism

Conversion of aspartate to asparagine, which is catalyzed by the enzyme asparagine synthetase.

Albinism

A genetic condition characterized by a lack of melanin, leading to reduced coloration of the skin, hair, and eyes.