Question

A polysaccharide that is used to determine the glomerular filtration rate is inulin, is extracted from the roots of
A. Dahlia
B. Gladiolus
C. Chrysanthemum
D. Sunflower

Answer 1

Hint:- Urine formation begins when a large amount of fluid that is virtually free of proteins is filtered from the glomerular capillaries into the Bowman's capsule. This process of filtration is termed as Glomerular filtration. As filtered fluid leaves Bowman's capsule and passes through the tubules, it is modified by tubular reabsorption and tubular secretion.

Complete step-by-step solution:-
● Most of the substances which are not being reabsorbed by the kidneys into the blood are
excreted through the urine completely.
● If a substance is freely filtered and is not reabsorbed by the renal tubules, then the rate at which
The substance excreted in urine is equal to the filtration rate of the substance by the kidneys.
● A substance that fits these criteria is Inulin, a polysaccharide molecule.
● Inulin is a linear polymer of Fructose.
● It is a water-soluble polysaccharide, and also the smallest storage polysaccharide.
● Inulin is found commonly in the roots of Dahlia and sometimes in the roots of Artichoke.
● The rate at which Inulin is cleared from blood plasma by the kidneys per unit time is called Inulin
clearance.
● Approximately 125 ml of plasma flowing through the kidneys must be filtered to deliver the 1
mg/ml of inulin that appears in the urine.
Thus the correct answer is option A.

Note:- Inulin is not being produced in the body, rather it is administered intravenously to a patient to measure GFR. It is considered a 'gold standard ' for estimating the glomerular filtration rate. If the amount of inulin administered is equal to the amount released then the kidneys are properly functioning otherwise severe renal complications may have occurred.