Transcribed Image Text: Remember that hexose kinase is an enzyme required for hexose metabolism, a process that takes a 6-carbon sugar and breaks it down into 2 pyruvate molecules. You

Transcribed Image Text: Remember that hexose kinase is an enzyme required for hexose metabolism, a process that takes a
6-carbon sugar and breaks it down into 2 pyruvate molecules.
You discover that rather than being hormonally regulated (as seen above in humans), hexose kinase
is part of an operon in prokaryotic organisms. This operon is known as the “hexose operon” and it
regulates expression of the complete set of enzymes needed to convert a hexose sugar into 2
pyruvate molecules.
Like the lac operon, the hexose operon is controlled by a separate regulatory protein under the control
of its own promoter (see the schematic of the operon below). The hexose regulatory protein is
sensitive to fatty acyl CoA levels. When all hexose fuel sources are depleted, the bacteria switch to
lipid metabolism and fatty acyl COA levels increase. This turns expression of the hexose operon off.
+1
+1
Regulatory Gene
Pregulator
Por
operon
Hexose Operon Genes
regulator promoter
operon promoter
Question 5
E) The regulatory protein that controls expression of the hexose operons is a transcriptional
ACTIVTOR or REPRESSOR (circle one).