Question

PART A

Correctly order the steps 1-8 as they occur during the transport of glucose via the phosphotransferase system (PTS):

HPr donates the phosphate group to enzyme IIA (EIIA); phosphoenolpyruvate is produced as an intermediate of glycolysis; EI donates the phosphate group to a histidine-rich protein (HPr); as it enters the cell glucose is phosphorylated by EIIB; phosphoenolpyruvate donates its high-energy phosphate group to enzyme I (EI); EIIA passes its phosphate group to Enzyme IIB (EIIB); glucose is transported across the membrane by enzyme IIC (EIIC); and the end product glucose-6-phosphate is now chemically different from the parent solute.

PART B

the phosphotransferase system is classified as a form of active transport because :

A. energy is in fact not required, because the solute is not being moved against its concentration gradient

B. it requires energy to chemically modify the transported solute

C. energy from the proton motive force is expended to bring the solute into the cell

D. ATP is hydrolyzed to effect a conformational change in the solute as it enters the cell

E. energy for the membrane transporter is provided by the electron transport chain

PART C

Over 20 different carbohydrates are transported by bacterial phosphotransferase systems. Some system components are shared, while others are specific to the sugar being transported. Sort the following system elements based on whether they are shared or unique. Items (6 items) (Drag and drop into the appropriate area below) EIIC EIIB EIIA HPr EI PEP

Answer 1

PART A: The sequence of events occurring during the transports of glucose via the phosphotransferase system (PTS) is as follows: 1. Phosphoenolpyruvate is produced as an intermediate of glycolysis. 2. Phosphoenolpyruvate donates its high-energy phosphate group to Enzyme I (EI). 3. El donates the phosphate group to a histidine-rich protein (HPr). 4. HPr donates the phosphate group to Enzyme IIA (EIIA). 5. EIIA passes its phosphate group to Enzyme IIB (EIIB). 6. Glucose is transported across the membrane by Enzyme IIC (EIIC). 7. As it enters the cell, glucose is phosphorylated by EIIB. 8. The end product, glucose-6-phosphate, is now chemically different from the parent solute. Part B: The phosphotransferase system is classified as a form of active transport because it requires energy to chemically modify the transported solute. Part C: Shared components Specific to each sugar HPT EIIB ΕΠΑ PEP EIIC