Question

Chemically hormones are
A. Biogenic amine only
B. Proteins, steroids, and biogenic amines
C. Proteins only
D. Steroid only

Answer 1

Hint: Hormones are chemical messengers released by glands without ducts to perform various functions. They are chemically classified under four categories- proteins and peptides, steroids, amino acids derivatives, and fatty acid derivatives.

Complete answer:
Hormones are chemical messengers because they transfer chemical signals to various body parts for definite functions. They are secreted directly into the blood without going through any ducts. They are produced by different glands of the body known as endocrine glands. It controls the entire system of the body and deficiency of even one can cause serious disorders.
Some hormones are also produced as neuro-transmitting signals which perform a dual function of transmitting messages from one neuron to another and also to the receptor to enable the organ to show its activity. Some neuro-transmitting hormones are Adrenaline.

There are four different categories of hormones-
-Protein and peptides- They are products of translation. Example- insulin,
-Steroid hormone- They are derivatives of cholesterol. Example-testosterone
-Amino acids derivatives-They are tyrosine-derived hormones like thyroid hormones and catecholamines.
-Fatty acid derivatives- prostaglandins, prostacyclins, leukotrienes, and thromboxanes.
Therefore, hormones cannot be only biogenic amines or proteins or steroids but it can be all the three.

Hence, the correct answer is option (B).

Note: The endocrine system has a connection with the nervous system. In the neuroendocrine secretion, the synaptic gap acts as signaling molecules when released into the circulation. Due to their mechanism of signal transmission, they are known as chemical messengers.
The delivery of the message to a particular organ is due to the receptor-ligand mechanism. The hormone acts as the ligand and reaches the receptor for transmitting the message.