This set of Molecular Endocrinology Multiple Choice Questions & Answers (MCQs) focuses on “Hormones are Chemically Diverse”.
1. What are the three classifications of hormones based on their mode of release into the target tissue?
a) Peptide, Catecholamines and eicosanoids
b) Endocrine, Paracrine and Autocrine
c) Steroids, Vitamins and Retinoids
d) Exocrine, Autocrine and Paracrine
View Answer
Explanation: Endocrine hormones are directly released into the blood stream and are carried to the target tissues in the body. Paracrine hormones are released and diffused into the target tissue through the extracellular space. Autocrine hormones are the ones that bind to the receptors in the same cell/tissue that release them.
2. What is an example of endocrine hormones among the options given below?
a) Steroid hormones
b) Insulin and glucagon
c) Oxytocin and Vasopressin
d) Thyroid hormones
View Answer
Explanation: It is also possible to distinguish hormones by the way they get to their target tissue from their point of release. Endocrine hormones are released into the blood and transported across the body to target cells. Examples are insulin and glucagon.
3. Eicosanoid hormone is an example of which class of releasing hormones?
a) Autocrine hormones
b) Endocrine hormones
c) Paracrine hormones
d) Water-soluble hormones
View Answer
Explanation: Eicosanoid hormones are an example of paracrine hormones. In the extracellular space, paracrine hormones are released and diffused to adjacent target cells. This classification of hormones is based on the way they get into their target tissues.
4. State whether True or False. Insects have highly developed system for hormonal regulation.
a) True
b) False
View Answer
Explanation: Insects and nematode worms, with basic mechanisms similar to those in humans, have strongly evolved structures for hormonal control. The study of hormone action is not as advanced in plants as in animals, but we do recognize that such pathways are shared between them. Plants often use hormonal signals to coordinate the actions of their tissues.
5. Peptide hormones are synthesized on which organelle in the cell?
a) Ribosomes
b) Endoplasmic Reticulum
c) Lysosomes
d) Golgi bodies
View Answer
Explanation: Peptide hormones are synthesized in the form of longer precursor proteins (prohormones) on ribosomes. They are then packaged into secretory vesicles and proteolytically separated to form active peptides.
6. Which of the following is an example of multiple hormones encoded by a single gene?
a) Insulin
b) Pro-opiomelanocortin
c) Thyrotropin Releasing Hormone (TRH)
d) Oxytocin
View Answer
Explanation: A perfect example of many hormones encoded by a single gene is pro-opiomelanocortin (POMC). A large polypeptide that is eventually carved into at least nine biologically active peptides encodes the POMC gene.
7. The concentration of peptide hormones in secretory granules is generally low. State whether True or False.
a) True
b) False
View Answer
Explanation: The accumulation of peptide hormones in secretory granules is so high that the substance of the vesicle is practically crystalline. A significant quantity of hormone is unexpectedly released by exocytosis. The capillaries that support endocrine glands which produce peptide hormones are permeable, so that the hormone molecules enter the bloodstream for transport to other target cells.
8. What molecules are produced when a peptide hormone binds to the receptors in the plasma membrane?
a) An intracellular enzyme is produced in the cytosol
b) Second messengers are produced in the plasma membrane
c) An intracellular enzyme is produced in the plasma membrane
d) Second messengers are produced in the cytosol
View Answer
Explanation: All peptide hormones function by binding to receptors in the plasma membrane. They allow a second messenger to be produced in the cytosol, which alters the function of an intracellular enzyme, which in turn changes the metabolism of the cell.
9. Which hormones among the following are collectively called catecholamines?
a) Epinephrine and norepinephrine
b) Insulin and glucagon
c) Thyroid hormones
d) Calcitonin and parathormone
View Answer
Explanation: Catecholamines, named after the structurally related compound catechol, are mainly the water-soluble compounds epinephrine (adrenaline) and norepinephrine (noradrenaline). They are synthesized from the amino acid tyrosine.
10. What is an example of molecules that can directly act both as a neurotransmitter and hormones?
a) Glucose
b) Epinephrine and norepinephrine
c) Parathormone and calcitonin
d) Estrogen and progesterone
View Answer
Explanation: Epinephrine and norepinephrine act as neurotransmitters at the smooth muscle neuromuscular junction as well as at the synapses of the brain. They also act as flight/fight hormones and a regulator of fuel metabolism in liver and muscle. Except for the anatomic difference in the chemical signaling of neuronal and hormonal signals, sometimes the same molecule act as neurotransmitter as well as hormones.
11. Prostaglandins, thromboxane, and leukotrienes are collectively known as which class of hormones?
a) Peptide hormones
b) Steroid hormones
c) Eicosanoid Hormones
d) Catecholamines
View Answer
Explanation: Prostaglandins, thromboxanes, and leukotrienes are collectively known as Eicosanoid Hormones. These hormones are obtained from the polyunsaturated fatty acid namely Arachidonate. This fatty acid has 20 carbon atoms in its parent chain.
12. Which enzyme helps in the release of eicosanoid hormones from the membrane phospholipids?
a) Protein kinase A
b) Glycogen phosphorylase b
c) Phosphatases
d) Phospholipase A2
View Answer
Explanation: Eicosanoids, unlike other hormone types, are not synthesized and processed in advance. They are produced from arachidonate when necessary and released enzymatically from membrane phospholipids by phospholipase A2.
13. Which hormone helps in the contraction of smooth muscles?
a) Prostaglandins
b) Thromboxanes
c) Eicosanoid
d) Steroids
View Answer
Explanation: Prostaglandins facilitate smooth muscle contraction, including that of the intestine and uterus (and can also be used to induce labor medically). Pressure and inflammation of all tissues are also mediated by them. Many anti-inflammatory drugs act by inhibiting steps in the synthetic process of prostaglandin.
14. Which class of Leukotrienes helps in the contraction of smooth muscles in the small intestine and pulmonary airways?
a) Cysteinyl leukotrienes
b) LTC4 and LTD4
c) D4 and E4
d) LTB4
View Answer
Explanation: Leukotrienes LTC4 and LTD4 work via plasma membrane receptors in order to induce contraction of smooth muscle in the intestine, pulmonary airways, and trachea. They are anaphylaxis mediators, which is a serious adverse immune reaction.
15. Which organic molecule present in the cell, helps in the formations of steroid hormones?
a) Phospholipids
b) Glycolipids
c) Cholesterol
d) Fats
View Answer
Explanation: The steroid hormones in most of the endocrine tissues are synthesized from cholesterol. They migrate across the bloodstream to their target cells attached to carrier proteins. All steroid hormones function to modify the level of expression of particular genes via nuclear receptors.
Sanfoundry Global Education & Learning Series – Molecular Endocrinology.
To practice all areas of Molecular Endocrinology, here is complete set of 1000+ Multiple Choice Questions and Answers.
If you find a mistake in question / option / answer, kindly take a screenshot and email to [email protected]
