(N/A) The $EMP$ pathway,commonly known as glycolysis,is the process of breaking down one molecule of glucose into two molecules of pyruvic acid. It occurs in the cytoplasm of the cell.
Key steps of the $EMP$ pathway:
$1$. Phosphorylation: Glucose is phosphorylated to Glucose-$6$-phosphate by the enzyme hexokinase,consuming one $ATP$.
$2$. Isomerization: Glucose-$6$-phosphate isomerizes to Fructose-$6$-phosphate.
$3$. Second Phosphorylation: Fructose-$6$-phosphate is converted to Fructose-$1,6$-bisphosphate,consuming another $ATP$.
$4$. Cleavage: Fructose-$1,6$-bisphosphate splits into two $3$-carbon molecules: Dihydroxyacetone phosphate $(DHAP)$ and $3$-phosphoglyceraldehyde ($PGAL$ or $G3P$).
$5$. Oxidation and Phosphorylation: $PGAL$ is oxidized to $1,3$-bisphosphoglycerate $(BPGA)$,reducing $NAD^+$ to $NADH + H^+$.
$6$. $ATP$ Generation: $BPGA$ is converted to $3$-phosphoglyceric acid $(PGA)$,generating $ATP$.
$7$. Final Steps: Through a series of reactions,$PGA$ is converted to Phosphoenolpyruvate $(PEP)$,and finally to Pyruvic acid,generating another $ATP$ per molecule.
Net yield per glucose molecule: $2$ Pyruvic acid,$2$ $ATP$ (net),and $2$ $NADH + H^+$.