Question

A major regulatory mechanism for multistep reaction is

• A. Presence of inhibitors
• B. Availability of activators
• C. Feed-back mechanism
• D. All of the above

Answer 1

Answer: (C)

Feed-back mechanism

The body has the various regulatory mechanism to control synthesis or secretion of various proteins, hormones etc. Excess of hormones affects the body, so it has a feedback mechanism to control the excess secretion of these hormones. The feedback mechanism is the process wherein the upregulation and downregulation of genes, hormones, homeostasis and other factors are controlled. There is a feedback mechanism of the thyroid hormone, which regulates the hypophyseal output of thyrotrophin and thereby the secretory rate of the thyroid gland. A diminished output of thyroid hormone stimulates the adenohypophysis to release increasing amounts of thyrotropin, and rising levels of thyroid hormone inhibit the adenohypophysis and diminish the secretion of thyrotropin. Thus, the correct answer is option C.