Indicate which of the following statements about gluconeogenesis is TRUE or FALS
ID: 530720 • Letter: I
Question
Indicate which of the following statements about gluconeogenesis is TRUE or FALSE
a) it occurs only in the mitochondiral mebrane
b) Precursors for hexoses include lactate, pyruvate, glycerol and alanine
c) The tree bypasses have G values near zero, whereas other GNG reactions have large negative G values
d) some reactions occur in the mitochondrial matix
Indicate whch of the following descriptions of glycogen and it synthesis and breakdown are TRUE and FALSE
1) branching increases the solubility of glycogen
2)glycogen phosphorylase and glycogen synthase are usually active simultaneously
3) glycogen synthess reuires conversion of glucose 1-phosphate to UDP glucose
4) the primer protein glycogenin is ruired for initiation of glycogen synthesis
Explanation / Answer
Ans 1 a) Gluconeogenesis occurs in cytoplasm and mitochondria so it does not occur only in the mitochondrial membrane. Therefore the given statement is false.
b) Gluconeogenesis is nothing but the formation of glucose , fructose and glucose is the major product of lactate ,pyruvate glycerol and alanine.Therefore precursor of hexose include lactate,pyruvate,alanine. The given statement is true .
c) Glucogenesis have three irreversible steps which are bypassed and we make glucogenesis spontaneous by adding 6 NTP so its gibbs free energy is negative but not near to zero. Therefore the given statement is false.
d) Some reaction occurs in the mitochondrial matrix as we can find the pyruvate carboxylase which is necessary for gluconeogenesis is found in the mitochondrial matrix. Therefore the given statement is true.
Ans 2 a) Branching increases the solubility of glycogen as branching increases the amount of glycogen and it can easily reach the enzyme involved in glycolysis.Therefore the statement is true.
b) glycogen phosphorylase is less active than glycogen synthase so they cannotbe active simultaneously. Therefore the given statement is false.
c) Yes , glycogen synthesis requires conversion of glucose 1-phosphate to UDP (uridine diphosphate ) which is an active form of glucose.Therefore the given statement is true.