Biochemistry: Amino Acid Conversion
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Questions and Answers

Which of the following is NOT a catecholamine mentioned in the overview?

  • Serotonin (correct)
  • Dopamine
  • Epinephrine
  • Norepinephrine

    • What is the primary location where epinephrine is synthesized?

  • Pancreas
  • Pituitary gland
  • Adrenal medulla (correct)
  • Liver

    • Catecholamines function primarily as neurotransmitters in which two systems?

  • Cardiovascular and digestive systems
  • Endocrine and immune systems
  • Muscular and integumentary systems
  • Central nervous system and peripheral nervous system (correct)

    • Which of the following functions is NOT listed for catecholamines?

    <p>Synthesis of neurotransmitters</p> Signup and view all the answers

    Which of the following is a characteristic feature of norepinephrine?

    <p>It has excitatory and inhibitory functions.</p> Signup and view all the answers

    What is the primary neurotransmitter that experiences decreased synthesis leading to movement disorders in the degenerative process?

    <p>Dopamine</p> Signup and view all the answers

    Which enzyme is responsible for the oxidative deamination in the context of dopamine metabolism?

    <p>Monoamine Oxidase</p> Signup and view all the answers

    What genetic factor is associated with the pathophysiology of Parkinson’s Disease?

    <p>Mutation in the gene encoding α-synuclein</p> Signup and view all the answers

    At what percentage decrease in dopamine levels do the signs of Parkinson's disease typically begin to appear?

    <p>80%</p> Signup and view all the answers

    What is the primary role of T3 in the thyroid hormone context?

    <p>Binding to receptors in cell nuclei</p> Signup and view all the answers

    Which of the following is NOT a proposed cause of Parkinsonism mentioned in the content?

    <p>Chronic alcohol consumption</p> Signup and view all the answers

    Which of the following is synthesized from tryptophan?

    <p>Melatonin</p> Signup and view all the answers

    Where is the majority of serotonin found in the body?

    <p>In intestinal mucosal cells</p> Signup and view all the answers

    What is the metabolic fate of T4 in the liver?

    <p>Deiodinated to form T3</p> Signup and view all the answers

    Which type of cells are primarily responsible for the synthesis of serotonin?

    <p>Neurons in the hypothalamus and brain stem</p> Signup and view all the answers

    What physiological role does serotonin NOT play?

    <p>Regulation of respiratory rate</p> Signup and view all the answers

    Which precursor is responsible for the formation of histamine?

    <p>Histidine</p> Signup and view all the answers

    Which neurotransmitter is identified as an inhibitory transmitter in the brain and spinal cord?

    <p>GABA</p> Signup and view all the answers

    What is the primary product formed when 5-hydroxyindoleacetaldehyde is oxidized by aldehyde dehydrogenase?

    <p>5-hydroxyindoleacetic acid (5-HIAA)</p> Signup and view all the answers

    Which functional group in antihistamine drugs contributes to their structural similarity to histamine?

    <p>Imidazole ring</p> Signup and view all the answers

    What co-factor is required for the enzymatic reaction involved in amino acid conversion to specialized products?

    <p>Pyridoxal phosphate</p> Signup and view all the answers

    How is creatinine excreted in relation to muscle mass in the body?

    <p>It is directly proportional to creatine phosphate content.</p> Signup and view all the answers

    What is the primary method through which creatinine is cleared from the plasma?

    <p>Filtration by the kidneys</p> Signup and view all the answers

    What is required as a reductant for the conversion of tryptophan to 5-hydroxytryptophan?

    <p>Tetrahydrobiopterin</p> Signup and view all the answers

    Which of the following functions predominantly involve serotonin?

    <p>All of the above</p> Signup and view all the answers

    What is the primary product of the oxidative deamination of 5-hydroxytryptamine (5-HT)?

    <p>5-hydroxyindoleacetaldehyde</p> Signup and view all the answers

    What role does histamine primarily serve in allergic reactions?

    <p>It acts as a potent vasodilator</p> Signup and view all the answers

    In what manner is histamine stored in the body?

    <p>In granules associated with ATP</p> Signup and view all the answers

    Which physiological process is NOT typically associated with serotonin?

    <p>Histamine degradation</p> Signup and view all the answers

    Which type of messenger is serotonin primarily classified as?

    <p>Chemical messenger mediating cellular responses</p> Signup and view all the answers

    What diseases or conditions can agents that interfere with histamine largely address?

    <p>Allergic reactions</p> Signup and view all the answers

    Study Notes

    Catecholamines

    • Biologically active amines, including dopamine, norepinephrine, and epinephrine.
    • Serve as neurotransmitters in the brain and autonomic nervous system (ANS).
    • Functions:
      • Building blocks for proteins.
      • Involved in degenerative processes.
    • Inactivation by:
      • Monoamine Oxidase (MAO): oxidative deamination occurring in neural tissues, gut, and liver.
      • Catechol-O-Methyltransferase (COMT): performs O-methylation using S-adenosylmethionine.
    • Genetic mutations affecting dopamine synthesis can lead to movement disorders, such as Parkinson’s disease.
    • Signs of Parkinson’s appear after an 80% decrease in dopamine levels in the nigrostriatal system.

    Glutamate

    • Precursor of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the brain and spinal cord.
    • GABA metabolism bypasses the α-ketoglutarate dehydrogenase step of the TCA cycle, leading to succinate.

    Tryptophan

    • Precursor of serotonin, melatonin, and oxidized NAD+.
    • Major serotonin concentration in intestinal mucosal cells, smaller amounts in platelets and the central nervous system.
    • Physiologic roles include pain perception, regulation of sleep, temperature, blood pressure, and smooth muscle contraction.
    • Synthesis involves Tryptophan Hydroxylase, requiring tetrahydrobiopterin and catalyzing the formation of 5-hydroxytryptophan (5-HTP).

    Histidine

    • Precursor of histamine.
    • Functions of histamine:
      • Potent vasodilator and neurotransmitter.
      • Mediates allergic and inflammatory responses as well as gastric acid secretion.
    • Secreted by mast cells in response to allergic reactions and trauma.
    • Antihistamine drugs counteract the effects of histamine by having structural similarities.

    General Notes on Amino Acid Derivatives

    • Degradation pathways often involve oxidative deamination via MAO.
    • Creatinine levels in urine can estimate muscle mass, correlated with creatine phosphate content.
    • Creatinine is efficiently cleared from plasma by kidneys; increased levels can indicate various physical conditions, including muscle atrophy.

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    Biochemistry Amino Acid Conversion PDF

    Description

    This quiz explores the conversion of amino acids into specialized products, focusing on catecholamines and their biological relevance. It covers the role of dopamine as a neurotransmitter and other biologically active amines. Engage with the content to deepen your understanding of biochemistry.

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