25 Questions
What is the metabolic role of tyrosine in the body?
Synthesis of dopamine
Which amino acid is synthesized from phenylalanine in the liver?
Tyrosine
Which amino acid is an essential amino acid?
Phenylalanine
What is the main function of melanin synthesized from tyrosine?
Protecting the skin from UV rays
What is the metabolic disorder characterized by an absence of the enzyme required for phenylalanine metabolism?
Phenylketonuria
Which of the following is a feature of albinism?
Deficiency in melanin production
What is the main cause of Hyperphenylalaninemia type 1?
Genetic deficiency of phenylalanine hydroxylase
What is the alternative pathway for oxidation of phenylalanine in Hyperphenylalaninemia type 1?
Conversion into phenylacetate, phenylpyruvate, and phenylactate
In Hyperphenylalaninemia type 1, what is the clinical manifestation related to skin color?
Light color of hair & skin
What is the diagnosis test for phenylketonuria?
Urine ferric chloride test
What is the recommended treatment for phenylketonuria in children?
Low concentrations of phenylalanine in the diet after age 6 years
What is the main cause of albinism?
Genetic deficiency of tyrosinase
What causes mental retardation and seizures in Hyperphenylalaninemia type 1?
Competitive inhibition of pyruvate transport to mitochondria by phenylpyruvate
What is the specific clinical manifestation in alkaptonuria related to urine color?
Blackish-brown urine when fresh
What is the most likely cause of ochronosis and a form of arthritis in alkaptonuria?
Build-up of homogentisate in connective tissues
What is the main biological function of protein synthesis in adults?
To replace constantly turning over proteins
Which compounds are synthesized from amino acids?
Purines and pyrimidines
What is the role of Krebs cycle in amino acid metabolism?
It provides missing elements for protein synthesis
Which enzyme is responsible for cleaving the basic amino acids from the C-terminal end of the peptide during protein digestion?
Pancreatic carboxypeptidases
What is the main function of large peptides and free amino acids in protein digestion?
Replacement of constantly turning over proteins
What is the main fate of the absorbed amino acids?
Incorporation into tissue proteins
Where does oxidative deamination of amino acids mainly occur?
Liver and kidney
What is the significance of L-glutamate dehydrogenase in oxidative deamination?
Conversion of alpha-ketoglutaric acid to glutamic acid
What is the primary metabolic fate of non-essential amino acids in the body?
Incorporation into tissue proteins
What is the main function of transamination in amino acid metabolism?
Transfer of the amino group to a suitable keto acid acceptor
This quiz covers the functions of tyrosine amino acid, phenylketonuria including its etiology, clinical presentation, diagnosis, and treatment, as well as the definition and etiology of albinism. It also explores the metabolic characteristics of phenylalanine and tyrosine amino acids.
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