Tadpoles of frog can be made to grow as giant sized tadpoles, if they are
administered antithyroid substance like thiourea
administered large amounts of thyroxine
reared on a diet rich in egg yolk
reared on a diet rich in both egg yolk and glucose.
A.
administered antithyroid substance like thiourea
Thyroxine, the principal hormone, of thyroid gland, is required for tissue differentiation and metamorphosis (the rapid transformation from the larval to the adult form) in amphibians. Thyroxine triggers a response from the hypothalamus, (probably by a genetic mechanism) followed by the production and release of TSH (Thyroid stimulating hormone), thus metamorphosis begins and tadpoles metamorphose into frogs. Thiourea is an organic compound of carbon, nitrogen, sulphur and hydrogen, with the formula CSN2H4, or (NH2)2CS. It is similar to urea, except that oxygen atom is replaced by a sulphur atom.
The source of somatostatin is same as that of
thyroxine and calcitonin
insulin and glucagon
somatotropin and prolactin
vasopresin and oxytocin
Which one of the following four secretions is correctly matched with its source, target and nature of action?
| Secretion | Source | Target | Action |
| Gastrin | Stomach lining | Oxyntic cells | Production of HCl |
| Inhibin | Sertoli cells | Hypothalamus | Inhibition of secretion of gonadotropin releasing hormone |
| Enterokinase | Duodenum | Gall bladder | Release of bile juice |
| Atrial Natiuretic Factor (ANF) | Sinu atrial node (SAN) M- cells of Atria | Juxta- glomerular apparatus (JGA) | Inhibition of release of renin |
Assertion: Diabetes insipidus is marked by excessive urination and too much thirst of water.
Reason: Anti-diuretic hormone (ADH) is secreted by the posterior lobe of pituitary gland,
If both Assertion and Reason are true and Reason is the correct explanation of Assertion
If both Assertion and Reason are true but Reason is not the correct explanation of Assertion
If Assertion is true but Reason is false
If both Assertion and Reason are false.
Which one of the following four glands is correctly matched with the accompanying description ?
Thyroid - hyperactivity in young children causes cretinism
Thymus - starts undergoing atrophy after puberty
Parathyroid - secretes parathormone which promotes movement of calcium ions from blood into bones during calcification
Pancreas - Delta cells of the Islets of Langerhans secrete a hormone which stimulates glycolysis in liver
Assertion : Aldosterone is a steroid hormone and is important in the control of sodium and potassium ion concentration in mammals.
Reason : It upgrades sodium ion concentration in the ECF by promoting reabsorption of sodium ions from renal tubules and excretion of potassium ions in urine.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false
Assertion: Our body secretes adrenaline in intense cold.
Reason: Adrenaline raises metabolic rate.
If both assertion and reason are true and reason is the correct explanation of assertion
If both assertion and reason are true but reason is not the correct explanation of assertion
If assertion is true but reason is false
If both assertion and reason are false.
