Final answer:
Glycated hemoglobin, or HbA1c, is the protein used to measure glucose levels over a period of about 3 months, which reflects the average blood sugar level and is important for diabetes management.
Step-by-step explanation:
The protein used to measure glucose levels over a period of about 3 months is glycated hemoglobin, also known as HbA1c. Through a process known as glycosylation, glucose molecules in the blood non-enzymatically attach to the hemoglobin in red blood cells. The amount of glucose that has attached to hemoglobin molecules over the lifespan of red blood cells (approximately 120 days) reflects the average level of blood sugar over that period. Because red blood cells have a lifespan of about 120 days, the measure of glycated hemoglobin provides an estimate of blood sugar levels over that timeframe, which is useful for the diagnosis and monitoring of diabetes mellitus.
Oligosaccharides, which form part of the glycosylation process, begin their synthesis in the rough endoplasmic reticulum (RER). As proteins travel through the Golgi vesicles, they receive terminal glycosylation which finalizes the glycoprotein synthesis, ultimately affecting the composition of the exterior cell surface.