Quick Biochemistry - Enzymes (Section 4)

  • 1
    Which of the following enzymes participates in the process of creating glucose from non-carbohydrate precursors?
    Cevap
    (B)
    Pyruvate carboxylase
  • 2
    Where is the enzyme that converts pyruvate to oxaloacetate found?
    Cevap
    (B)
    Mitochondria
  • 3
    What molecule is essential for the conversion of oxaloacetate to phosphoenolpyruvate by phosphoenolpyruvate carboxykinase?
    Cevap
    (D)
    GTP
  • 4
    In which of the following tissues is glucose 6-phosphatase found?
    Cevap
    (A)
    Liver
  • 5
    Which molecule acts as a regulator in the production of oxaloacetate from bicarbonate and pyruvate, a reaction facilitated by pyruvate carboxylase?
    Cevap
    (A)
    Acetyl CoA
  • 6
    How many energy-carrying molecules are needed to turn two lactic acid molecules into glucose in the liver of animals?
    Cevap
    (D)
    6
  • 7
    What compound is provided by the uronic acid pathway to assist in the modification of various substances before they are removed through urine?
    Cevap
    (A)
    Active glucuronate
  • 8
    UDP glucose dehydrogenase utilizes which coenzyme to convert UDP glucose to UDP glucurronate?
    Cevap
    (A)
    NAD+
  • 9
    What substance is found in elevated levels in the urine of individuals with pentosuria, a genetic condition?
    Cevap
    (A)
    L-xylulose
  • 10
    Which type of enzyme is deficient in individuals with essential pentosuria?
    Cevap
    (A)
    Reductase
  • 11
    In which organ does the body create galactose from glucose?
    Cevap
    (A)
    Mammary gland
  • 12
    In which organ is galactose easily changed back into glucose?
    Cevap
    (A)
    Liver
  • 13
    What enzyme facilitates the conversion of galactose 1-phosphate to uridine diphosphate galactose?
    Cevap
    (B)
    Galactose 1-phosphate uridyl transferase
  • 14
    The most common reason for galactosemia is a lack of which of the following?
    Cevap
    (A)
    Galactose 1-phosphate and uridyl transferase
  • 15
    Which enzyme is responsible for converting fructose into sorbitol?
    Cevap
    (B)
    Aldose reductase
  • 16
    Why does the specific fructokinase found in the liver have a high affinity for fructose?
    Cevap
    (B)
    K for fructose is very low
  • 17
    Which enzyme's activity is not influenced by insulin?
    Cevap
    (B)
    Fructokinase
  • 18
    The buildup of which substance is a factor in the development of diabetic cataracts?
    Cevap
    (C)
    Sorbitol
  • 19
    What enzyme is missing in individuals with hereditary fructose intolerance?
    Cevap
    (A)
    Aldalose B
  • 20
    Which liver enzyme is absent in individuals with essential fructosuria?
    Cevap
    (D)
    Fructokinase
  • 21
    In healthy people, when does glucose appear in urine, based on venous blood glucose concentration?
    Cevap
    (D)
    9.5-10 mmol/L
  • 22
    What is the primary action of phlorizin in biological systems?
    Cevap
    (A)
    Renal tubular reabsorption of glucose
  • 23
    Which of the following best describes the typical blood glucose and urine characteristics in renal glycosuria?
    Cevap
    (C)
    Normal blood glucose level with glycosuria
  • 24
    In individuals with a sensitivity to fava beans, which enzyme deficiency is the primary cause of acute hemolytic anemia?
    Cevap
    (B)
    G-6-PD
  • 25
    What enzyme deficiency is linked to hemolytic episodes triggered by the antimalarial drug primaquine?
    Cevap
    (B)
    Glucose-6-phosphate dehydrogenase
  • 26
    What is the optimal pH range for the activity of gastric lipase?
    Cevap
    (A)
    3.0-6.0
  • 27
    What is the ideal pH for pancreatic lipase to function most effectively?
    Cevap
    (C)
    6.0
  • 28
    Which of the following substances activates gastric lipase?
    Cevap
    (A)
    Bile salts
  • 29
    Which of the options below represents a type of enzyme inhibition?
    Cevap
    (D)
    All of these
  • 30
    Which enzyme is responsible for the conversion of acyl-CoA to Δ²-trans-enoyl-CoA?
    Cevap
    (B)
    Acyl-CoA dehydrogenase
  • 31
    Which enzyme splits 3-ketoacyl-CoA at the 2, 3 position during β-oxidation?
    Cevap
    (D)
    Thiolase
  • 32
    What compound is produced alongside acetyl-CoA when fatty acids with an odd number of carbon atoms undergo oxidation?
    Cevap
    (B)
    Propionyl-CoA
  • 33
    Considering the α-oxidation of palmitic acid, what is the approximate yield of high-energy phosphates for each of the initial 7 acetyl-CoA molecules produced?
    Cevap
    (D)
    35
  • 34
    Approximately how many ATP molecules are gained net per mole of palmitic acid upon complete oxidation?
    Cevap
    (C)
    129
  • 35
    What type of enzymes are involved in ω-oxidation, a generally minor pathway?
    Cevap
    (C)
    Cytochrome c
  • 36
    In which tissue has α-oxidation, the process of removing a single carbon atom from the carboxyl end of a molecule, been found?
    Cevap
    (A)
    Brain tissue
  • 37
    In the β-oxidation pathway, what coenzyme is required by acyl-CoA dehydrogenase?
    Cevap
    (D)
    FAD
  • 38
    What coenzyme is essential for the dehydrogenation of 3-hydroxy acyl-CoA?
    Cevap
    (C)
    NAD
  • 39
    Under standard conditions, what is the typical maximum concentration of ketone bodies in the bloodstream?
    Cevap
    (A)
    0.2 mmol/L
  • 40
    Under normal conditions, how much ketone bodies are typically eliminated through urine in humans within a 24-hour period?
    Cevap
    (A)
    1 mg/24 hr
  • 41
    Which organ is primarily responsible for producing ketone bodies in significant amounts for circulation?
    Cevap
    (C)
    Liver
  • 42
    What molecule initiates the process of ketogenesis?
    Cevap
    (C)
    Acetoacetyl-CoA
  • 43
    The enzymes involved in creating ketone bodies are predominantly located within the
    Cevap
    (A)
    Mitochondria
  • 44
    Where can the synthesis of 3-hydroxy-3-methylglutaryl-CoA take place?
    Cevap
    (C)
    In both the cytosol and mitochondria
  • 45
    In the liver's process of making acetoacetate from acetyl-CoA, which molecule directly precedes acetoacetate?
    Cevap
    (A)
    Acetoacetyl-CoA
  • 46
    Ketone bodies provide energy for which type of tissues?
    Cevap
    (A)
    Tissues outside the liver
  • 47
    In tissues other than the liver, how is acetoacetate typically used?
    Cevap
    (B)
    Via Succinyl-CoA
  • 48
    What does ketosis indicate?
    Cevap
    (B)
    Heightened fatty acid breakdown
  • 49
    Which medical condition is linked with ketosis?
    Cevap
    (B)
    Diabetes mellitus
  • 50
    The primary site for new fatty acid synthesis is the
    Cevap
    (A)
    Cytosol