NEET Practice Questions (MCQs) with Answers & Solutions

The text states: 'The classical definition of hormone as a chemical produced by endocrine glands and released into the blood and transported to a distantly located target organ has current scientific definition as follows: Hormones are non-nutrient chemicals which act as intercellular messengers and are produced in trace amounts. The new definition covers a number of new molecules in addition to the hormones secreted by the organised endocrine glands.'

The NCERT text lists 'second messengers (e.g., cyclic AMP, IP3, Ca++ etc)'. Insulin and estrogen are hormones, and DNA is the genetic material, not a second messenger.

The text states: 'Hormones which interact with intracellular receptors (e.g., steroid hormones, iodothyronines, etc.) mostly regulate gene expression or chromosome function by the interaction of hormone-receptor complex with the genome.' Intracellular receptors are 'mostly nuclear receptors (present in the nucleus)'.

The NCERT text mentions: 'The juxtaglomerular cells of kidney produce a peptide hormone called erythropoietin'. This directly classifies it as a peptide hormone.

The NCERT text clearly states: 'Each receptor is specific to one hormone only and hence receptors are specific'.

The NCERT context lists 'steroids (e.g., cortisol, testosterone, estradiol and progesterone)' as a category of hormones based on their chemical nature.

The text states: 'The neural coordination is fast but short-lived... a special kind of coordination and integration has to be provided. This function is carried out by hormones.'

The NCERT text mentions: 'Hormone receptors present on the cell membrane of the target cells are called membrane-bound receptors and the receptors present inside the target cell are called intracellular receptors, mostly nuclear receptors (present in the nucleus)'.

The NCERT text states: 'The branch of knowledge dealing with these aspects [identification, nomenclature and classification of organisms] is referred to as taxonomy.'

The context mentions: 'The scope of systematics was later enlarged to include identification, nomenclature and classification. Systematics takes into account evolutionary relationships between organisms.'