strong textenter image description here

My take on question-

  1. All hormone are not water soluble, some are fat soluble also so this option is definiely wrong.

  2. Thyroxine Hormone is do stored in the body in Follicle of thyroid gland, All is not mentioned so we can say this option is not wrong.

  3. Hormones are destroyed after use, and that's a fact, so this option is also correct.

Now here comes the tough part

  1. Hormone do not participate in the metabolic activities, well signaling is not participating as far as I think, Hormones do not act as A Substrate or as A enzyme, so this option seems correct to me, but I am not sure, Does Signalling means Participating??

  2. The molecules of most of the hormones are small. I don't know what to make of it, well if compare simple one molecule Hormones like Epinephrine and Melatonin to Peptide hormone, Peptide hormone seems large,this options is so Ambiguous I need help in this


Ah, good old bad exam questions. Invoking subjective, arbitrary and ambiguous adjectives and verbs. My very rough and blunt appraisal would be that many hormones are indeed widely and relatively small -ish. They are often 're-usable' after binding since their binding to receptors is often reversible. Some endocrine cells store hormones, while other hormones are entirely in flux. Some hormones are soluble, others aren't, yet others are not but are emulsified by things like micelles (e.g. casein). Some hormones certainly participate in metabolism; think insulin's role in glucose metabolism.

First, let's just acknowledge the lax definition of hormone before we go into each one-by-one.

  • Most hormones are small molecules

Generally correct. I think most biologists would be okay with saying this is generally true. They are necessarily small in many cases because they function in long-range endocrine or paracrine signaling and must satisfy preconditions for such functions. Consequently, it's easier to make a long list with small molecular weight hormones than it is to make a list of large molecular weight hormones.

  • Hormones are destroyed after use

Generally incorrect. That depends what destroyed and use mean. If by use one means binding to a receptor to transduce a cascade, then a single hormone molecule typically can be re-bound to the same receptor on one cell, and/or can be received by different cells. Some hormones are 'destroyed' by endocytosis and subsequent lysis within the endomembrane system, others have to be inactivated by proteases or filtered from bodily fluids by, say, kidneys.

  • Hormones are stored in the body

Some are, others are not. Steroid hormones, being lipophilic, cannot be stored in vesicles, and so are synthesized in mitochondria and smooth endoplasmic reticulum as precursors. I would be cautious to claim that precursors are hormones, so let's say with confidence that these cannot be stored. However, many other hormones that are usually not lipophilic, such as amino-acid based hormones, are typically stored in secretory granules. See here or here.

  • All hormones are soluble in water

False. Counterexample: steroid hormones are insoluble in water, which is why they are carried by transport proteins in the aqueous medium of the blood.

  • Hormones do not participate in metabolic activities

False. Counterexample: insulin.

  • $\begingroup$ Hormones do not participate in metabolic activities False. Counterexample: insulin , Isnt the participation means, being the substrate or enzyme, Insulin does signal transduction by kinases , which ultimately leads to GLUT 4 to insert in cell membrane, this is isn't metabolism , anbolic or catabolic, as the signal transduction only lead to influx of glucose, not in metabolism of glucose, in short i am not able to digest that signal transduction is also a paraticpitation in metabolism, it is facilitating metabolism $\endgroup$ Aug 18 at 13:25
  • 1
    $\begingroup$ You are right that insulin does not directly participate in chemical pathways. It is a central player in the metabolism of glucose. It directly influences the availability of glucose for glycolysis! ATP is catabolically consumed to begin glycolysis. How about the case of adrenaline? Does adrenaline not increase the availability of oxygen? This is semantic confusion that the question leaves open to interpretation, hence the preface. But certainly one can reason that metabolism, defined as the total set of life-sustaining chemical reactions in organisms, excludes insulin as a participant! $\endgroup$
    – S Pr
    Aug 19 at 8:57

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.