Biochemistry Exam 3: Hemostasis and Clotting
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Questions and Answers

What unique amino acid is found in elastin and results from lysine modifications?

  • Hydroxyapatite
  • Collagen
  • Desmosine (correct)
  • Fibrillin

    • What primary function do fibrillin microfibrils serve in the body?

  • Facilitate chemical signaling
  • Store calcium for bone health
  • Assist in the elastic fiber formation (correct)
  • Provide structural strength in bones

    • Which disease is associated with defects in elastin-related components?

  • Ehlers-Danlos syndrome
  • Scurvy
  • Osteoporosis
  • Marfan syndrome (correct)

    • What is the role of osteoblasts in bone formation?

    <p>Build bone tissue</p> Signup and view all the answers

    What is a major component that provides hardness to bones?

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

    How are the collagen fibers organized in bone structure?

    <p>In brick-like shapes</p> Signup and view all the answers

    What prevents the formation of hydroxyapatite crystals in bones?

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

    What is the primary role of heparin in the blood coagulation process?

    <p>Binds to antithrombin to enhance its action</p> Signup and view all the answers

    What type of bone is focused on structural support and contains osteons?

    <p>Cortical bone</p> Signup and view all the answers

    Which test evaluates the extrinsic pathway in the coagulation process?

    <p>PT test</p> Signup and view all the answers

    What does a prolonged prothrombin time indicate?

    <p>Deficiency in extrinsic pathway factors or vitamin K</p> Signup and view all the answers

    What is the effect of warfarin on blood coagulation?

    <p>Acts on liver cells to reduce clotting factors</p> Signup and view all the answers

    What effect does lead have on heme synthesis?

    <p>Replaces Fe2+ in ferrochelatase</p> Signup and view all the answers

    Which condition is characterized by a deficiency of platelets?

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

    What is the role of calcium chloride in the PT test?

    <p>To start the coagulation process</p> Signup and view all the answers

    What happens to d-ala levels in the case of lead poisoning?

    <p>d-ala is overproduced</p> Signup and view all the answers

    Which factor primarily regulates the transfer of iron from intestinal cells into the bloodstream?

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

    Which of the following describes fibrinolysis?

    <p>The breakdown of vascular clots</p> Signup and view all the answers

    Why is the bleeding time test not commonly used anymore?

    <p>It has high variability in results</p> Signup and view all the answers

    What is the outcome of high hepcidin levels in the body?

    <p>Decreased iron uptake</p> Signup and view all the answers

    What is bilirubin a product of?

    <p>Conversion of hemoglobin</p> Signup and view all the answers

    How is iron stored within cells?

    <p>As ferritin</p> Signup and view all the answers

    What occurs to bilirubin when it accumulates in the body?

    <p>It leads to jaundice</p> Signup and view all the answers

    Which condition leads to low heme production due to depressed d-ala synthesis?

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

    What role does estrogen play in bone density regulation?

    <p>Decreases interleukin-6 production</p> Signup and view all the answers

    What is the primary role of calcium in bone and teeth?

    <p>Forms calcium phosphate, a structural component</p> Signup and view all the answers

    Which hormone is primarily responsible for stimulating bone resorption?

    <p>Parathyroid hormone (PTH)</p> Signup and view all the answers

    Which statement best describes the function of osteoblasts?

    <p>They are involved in bone formation.</p> Signup and view all the answers

    How does calcitonin affect calcium levels in the body?

    <p>It inhibits osteoclastic activity.</p> Signup and view all the answers

    What triggers the release of parathyroid hormone (PTH)?

    <p>Low blood calcium levels</p> Signup and view all the answers

    What is the role of vitamin D in calcium homeostasis?

    <p>It promotes calcium reabsorption in the kidney.</p> Signup and view all the answers

    What cellular effect does Ca2+ have regarding muscle function?

    <p>Activates blood platelets</p> Signup and view all the answers

    What is the immediate response of parathyroid glands to low serum calcium levels?

    <p>Release parathyroid hormone (PTH)</p> Signup and view all the answers

    How does hyperparathyroidism primarily affect bone health?

    <p>Stimulates osteoclast activity to degrade bone</p> Signup and view all the answers

    What role does calcitonin play in calcium homeostasis?

    <p>Inhibits bone resorption and stimulates calcium excretion</p> Signup and view all the answers

    What occurs when plasma calcium levels are high?

    <p>Osteoclast activity is decreased</p> Signup and view all the answers

    Which of the following is NOT a consequence of hypoparathyroidism?

    <p>Increased bone resorption</p> Signup and view all the answers

    What effect does excessive vitamin D intake have on calcium homeostasis?

    <p>Increases calcium resorption from bones</p> Signup and view all the answers

    What happens during chronic low extracellular calcium levels?

    <p>Increased production of PTH mRNA</p> Signup and view all the answers

    What is the primary function of vitamin D in relation to calcium homeostasis?

    <p>Stimulates calcium absorption from the gut</p> Signup and view all the answers

    What is the primary component of the polysaccharides found in dental plaque?

    <p>Glucose polymers</p> Signup and view all the answers

    Which of the following statements accurately describes the anaerobic environment in fully developed dental plaque?

    <p>It limits access to oxygen for bacteria.</p> Signup and view all the answers

    Which cancer is the most common type of oral cancer?

    <p>Squamous cell carcinoma</p> Signup and view all the answers

    What is a major risk factor associated with the development of oral cancer?

    <p>Tobacco use</p> Signup and view all the answers

    How does fluoride contribute to dental health?

    <p>It inhibits demineralization.</p> Signup and view all the answers

    Which area is NOT typically associated with the development of squamous cell carcinoma?

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

    What is the consequence of metabolic acids not diffusing out of dental plaque quickly?

    <p>Acidic environment contributing to tooth demineralization</p> Signup and view all the answers

    How is oral cancer occurrence related to age and gender?

    <p>More common in older people than younger people</p> Signup and view all the answers

    Study Notes

    Biochemistry Exam 3 Study Notes

    • Hemostasis and Blood Clotting:

      • Clotting begins with physical aggregation of platelets, which are small, non-nucleated cells circulating in the blood.
      • Platelet activation occurs upon contact with subendothelium and is triggered by several molecules (collagen, thromboxane A2, ADP).
      • Platelet activation involves a cascade of events including the production of second messengers, such as IP3, leading to calcium release, and platelet activation.
      • Inactive platelets have surface receptors for molecules like PGI2, which antagonizes platelet activation by inhibiting calcium release, and TXA2 and ADP, which facilitate aggregation and coagulation.
      • Blood clotting is triggered by external or internal injury to the endothelial cells.
      • The main processes of hemostasis include: vasoconstriction, platelet plug formation (adhesion, activation, and aggregation), and the coagulation cascade.
      • Platelet aggregation is a fragile process, relying on non-covalent bonds to hold platelets together.
      • The coagulation cascade is complex, involving various clotting factors that interact in a specific sequence.
      • Calcium, and vitamin K, play critical roles in the clotting cascade; they are cofactors for specific clotting factors, including factors II, VII, IX, and X.

    • Calcium and Vitamin K in Blood Clotting:

      • Clotting factors require calcium for proper functioning.
      • Vitamin K is crucial in several steps of the blood coagulation cascade. It converts specific amino acids into carboxylated forms to allow them to bind calcium properly allowing clotting to occur.

    • Natural and Pharmacological Anticoagulants:

      • Antithrombin III is a natural anticoagulant. Heparin works by accelerating the action of antithrombin III.
      • Aspirin and warfarin are pharmacological inhibitors of coagulation that interfere with platelet aggregation and coagulation pathways respectively.
      • Heparin is an anticoagulant which helps with fibrinolysis, preventing blood clots.

    • Blood Clotting Tests:

      • Prothrombin time (PT) tests for the extrinsic pathway. Activated partial thromboplastin time (PTT) tests for the intrinsic pathway. Bleeding time measures primary hemostasis.

    • Heme Biosynthesis:

      • Heme is a prosthetic group for several proteins, including hemoglobin and myoglobin, crucial for oxygen transport.
      • Heme synthesis involves sequential steps in mitochondria and cytoplasm in cells.
      • Heme synthesis is regulated depending on the need level for the cell needing it.
      • Lead poisoning can interfere with the synthesis of heme. This is very harmful as it affects the bone marrow specifically where red blood cells and blood cells are produced.

    • Iron Metabolism:

      • Iron is an essential component for heme synthesis, and plays an important part in the absorption, transport and storage of iron.
      • Iron balance is maintained by regulatory mechanisms involving peptides such as hepcidin, transferrin and ferritin

    • Bilirubin Metabolism:

      • During heme degradation, bilirubin is produced from hemoglobin breakdown (as byproduct).
      • Bilirubin is further processed and excreted in the bile, where it is eventually converted to stercobilin and excreted in feces.

    • Neonatal Jaundice and UV light:

      • Bilirubin is toxic to infants who lack a blood-brain barrier. Accumulating bilirubin in fatty tissues of newborns can be treated through phototherapy, using UV light.

    • Other Details:

      • Hemoglobin is broken down to cause the breakdown of biliverdin, which is further reduced to bilirubin.
      • Bilirubin is a yellow pigment and is excreted in the urine.

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    Description

    Prepare for Biochemistry Exam 3 with this focused quiz on hemostasis and blood clotting. Explore the intricate processes of platelet activation, aggregation, and the coagulation cascade essential for understanding blood function. Test your knowledge and ensure you're ready for the exam!

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