Answer:
Proteins are large molecules that cannot be transported efficiently across the membrane via transport proteins.
Step-by-step explanation:
Insulin is a protein hormone or a peptide hormone.
The pancreas in the body secretes insulin hormone. Insulin hormone is used to absorb the glucose or sugar from the carbohydrates that are provided from the food we eat in the form of energy for our body. This energy is used by the body to perform different functions. Insulin also stores this energy for future use.
Pancreas secrete insulin by the process of exocytosis. It is a transport process where the cell transport molecules through a energy dependent process.
Thus the answer is
Proteins are large molecules that cannot be transported efficiently across the membrane via transport proteins.