Question

Insulin is a/an
A. Vitamin
B. Lipid
C. Hormone
D. Enzyme

Answer 1

Hint: Hormones are chemical messengers which are secreted by the ductless glands called endocrine glands. Hormones coordinate different physical and mental activities of the body and maintain a steady-state. Thyroxine, insulin, adrenalin are some of the examples of hormones.

Complete answer:
Since the endocrine gland does not have duct, its secretion is directly poured into the bloodstream which carries them to organs and tissues of the body to exert their functions. There are different types of endocrine glands such as pituitary glands, thyroid glands, pancreas located at different parts in the body.
The pancreas is an organ of an alimentary canal. It is a leaf-like organ located just below the stomach. The pancreas is composed of two major tissues such as the acini and islets of Langerhans. The endocrine part of the pancreas is the islets of Langerhans.The islets of Langerhans are composed of alpha cells and beta cells which secrete hormones glucagon and insulin respectively directly into the bloodstream. Insulin regulates glucose concentrations in the blood. If the blood glucose concentration is too high, the pancreas produces the hormone insulin, this causes glucose to move from the blood into the cells. In liver and muscle cells excess glucose is converted to glycogen to be used later.

Thus option C. Hormone is the correct answer.

Additional information:
The Acini tissue of pancreas is the exocrine part that releases pancreatic juice that contains digestive enzymes into the duodenum of the small intestine. In the final digestion of carbohydrates, protein and fats occur in the duodenum. The enzymes include: Protein digesting enzymes trypsin and chymotrypsin. They break down protein into dipeptides and amino acids. Pancreatic amylase which digests starches into sugar. Lipase in association with bile breaks down fats into fatty acids and cholesterol.

Note:
Insulin is a hormone which promotes glucose utilization by the body cells and stimulates deposition of extra glucose in the blood as glycogen in the liver.