Correctly order the steps as they occur during the transport of glucose via the
ID: 147606 • Letter: C
Question
Correctly order the steps as they occur during the transport of glucose via the phosphotransferase system (PTS):
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As it enters the cell, glucose is phosphorylated by EIIB.
HPr donates the phosphate group to Enzyme IIA (EIIA).
EIIA passes its phosphate group to Enzyme IIB (EIIB).
Phosphoenolpyruvate is produced as an intermediate of glycolysis.
Phosphoenolpyruvate donates its high-energy phosphate group to Enzyme I (EI).
The end product, glucose-6-phosphate, is now chemically different from the parent solute.
EI donates the phosphate group to a histidine-rich protein (HPr).
Glucose is transported across the membrane by Enzyme IIC (EIIC).
Explanation / Answer
The phosphoenolpyruvate (PEP)-dependent phosphotransferase system (PTS) is an important mechanism in bacteria used for the uptake of carbohydrates (hexoses, hexitols and disaccharides). The source of energy is from PEP. The PTS constitutes two components- Enzyme I (EI) and Histidine phosphocarrier protein (HPr). It also contains Enzyme II (EII) or the membrane-bound sugar-specific permeases.
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. EI 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.