Question

1. elevated levels of insulin favors glycolysis and inhibits gluconeogenesis because:

there is increased transcription of the gene for pepck
there is decreased availability of gluconeogenic substrates
fatty acid oxidation is increased, thereby producing more acetyl co - enzyme a which is an allosteric regulator
pyruvate kinase undergoes dephosphorylation; hence, its action is inhibited.

Explanation:

Insulin reduces gluconeogenesis by decreasing gluconeogenic substrate availability and also promotes glycolysis. High insulin levels do not increase PEP - CK gene transcription, fatty acid oxidation is not increased in a way to inhibit gluconeogenesis as described here, and pyruvate kinase is activated (phosphorylated) by insulin - related pathways, not inhibited by dephosphorylation in this context.

Answer:

There is decreased availability of gluconeogenic substrates