Cards (47)

    • What are the two main endogenous energy stores?
      Carbohydrates and lipids
    • What is the primary form of carbohydrate storage in the body?
      Glycogen
    • What is the structure of glycogen?
      It is a branched polymer of glucose
    • How is glycogen made easily accessible as an energy store?
      Through 1,4 and 1,6 linkages
    • What is the role of glycogen in the liver?
      To supply glucose to the brain and tissues
    • What is the role of glycogen in muscles?
      For energy needs during exercise
    • How long can glycogen supply energy?
      Up to 24 hours
    • What are the three stages of glycogen synthesis?
      1. Activation
      2. Polymerisation
      3. Formation of branched molecule
    • What is the first step in glycogen activation?
      Conversion to glucose-1-phosphate
    • Which enzyme is responsible for the conversion to glucose-1-phosphate?
      Phosphoglucomutase
    • What drives the formation of UDP-glucose?
      Hydrolysis of PPi
    • What enzyme is used to form UDP-glucose?
      UDP-glucose pyrophosphorylase
    • What is needed for the polymerisation of glycogen?
      A primer of small polysaccharide unit
    • What enzyme is responsible for glycogen polymerisation?
      Glycogen synthase
    • What does the branching enzyme do during glycogen synthesis?
      Transfers a block of residues to form a branch
    • What are the steps involved in glycogen mobilisation?
      1. Phosphorolysis
      2. Debranching
      3. Further phosphorolysis
    • What is the final product of glycogen mobilisation?
      Glucose 6-phosphate
    • How is glucose 6-phosphate used in the body?
      In glycolysis and pentose phosphate pathway
    • What happens to glucose 6-phosphate in the liver?
      It is dephosphorylated and released into blood
    • Which enzyme is used in the phosphorolysis of glycogen?
      Glycogen phosphorylase
    • What are the two functions of the bifunctional enzyme in debranching?
      Transferase and α-1,6-glucosidase
    • What are glycogen storage diseases caused by?
      • Defective enzymes
      • 13 well-documented types
    • What is Type I glycogen storage disease known as?
      Von Gierke’s disease
    • What defect is associated with Von Gierke’s disease?
      Defect in phosphatase for glucose-6-phosphate
    • What is Type V glycogen storage disease known as?
      McArdle disease
    • What defect is associated with McArdle disease?
      Defect in muscle phosphorylase
    • What are triglycerides composed of?
      Three fatty acids and glycerol
    • What is another name for triglycerides?
      Triacylglycerols
    • Where are triglycerides primarily stored?
      In adipose tissue
    • Where are triglycerides mainly synthesised?
      In the liver
    • What initiates triglyceride synthesis?
      On the endoplasmic reticulum or mitochondrial membrane
    • What is the starting point for triglyceride synthesis?
      Glycerol-3-phosphate
    • From where is glycerol-3-phosphate mainly derived?
      From dihydroxyacetone phosphate (DHAP)
    • What is the first step in the formation of phosphatidate?
      Transfer of 2 fatty acids from fatty acyl CoA
    • What enzyme is used to form phosphatidate?
      Glycerol phosphate acyl transferase
    • What is the product of the first step in triglyceride formation?
      Diacylglycerol-3-phosphate
    • What are the two reactions involved in the formation of triglyceride?
      Removal of phosphate and addition of third fatty acid
    • What is the intermediate in triglyceride formation?
      Diacylglycerol (DAG)
    • What enzyme complexes are involved in triglyceride formation?
      Specific phosphatase and diglyceride acyltransferase
    • What are the steps involved in fat mobilisation for energy?
      1. Mobilisation by degradation to fatty acids and glycerol
      2. Fatty acids activated and transported into mitochondria
      3. Undergo β-oxidation
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