| Assertion (A): | Urea is the primary nitrogenous waste in humans. |
| Reason (R): | It is less toxic and more soluble in water compared to ammonia. |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A) |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | (A) is False but (R) is True. |
To maintain the pH and ionic balance of the body fluids, the proximal convoluted tubule selectively secretes all the following into the filtrate except:
| I. | Hydrogen ion | II. | Potassium ion |
| III. | Ammonia | IV. | Bicarbonate ion |
| I: | They are located at the level of T12 – L2-L3 vertebrae |
| II: | Left kidney is slightly lower placed than the right kidney |
| I: | is a fine capillary network around the renal tubule formed by efferent arteriole. |
| II: | runs parallel to the Henle’s loop in juxtamedullary nephrons. |
| III: | is absent or highly reduced in cortical nephrons. |
| I: | Each kidney of an adult human measures 10-12 cm in length, 5-7 cm in width and 2-3 cm in thickness. |
| II: | The DCTs of many nephrons open into a straight tube called collecting duct. |
| III: | Each nephron has two parts – the glomerulus and the renal tubule. |
| IV: | The renal tubule begins with the proximal convoluted tubule. |
| 1. | Only I and II | 2. | Only I, II and III |
| 3. | Only II and III | 4. | I, II, III and IV |
Potassium ions:
| I: | are filtered at the glomerulus |
| II: | are reabsorbed at the PCT |
| III: | are secreted at DCT |
| 1. | I & II only | 2. | I & III only |
| 3. | II & III only | 4. | I, II & III |
| Assertion (A): | Na+ reabsorption from glomerular filtrate occurs in PCT, ascending limb of loop of Henle and collecting duct |
| Reason (R): | Na+ is always reabsorbed by passive process in PCT, ascending limb of loop of Henle and collecting duct |
| 1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
| 3. | (A) is True but (R) is False. |
| 4. | Both (A) and (R) are False. |
Complete the analogy with respect to reabsorption
PCT : Glucose and amino acids :: DCT : _____
1. K+ and H+
2. H+ and
3. NaCl and
4. K+ and H2O
Excretion of dilute urine requires
| 1. | relative permeability of the distal tubule to water |
| 2. | transport of sodium and chloride ions out of the descending loop of Henle |
| 3. | the presence of ADH |
| 4. | impermeability of the collecting tubule to water |
| Assertion (A): | The ascending limb of loop of Henle is also called the diluting segment of the nephron. |
| Reason (R): | In the ascending portion, the loop becomes impermeable to water and the cells of the loop actively reabsorb solutes from the luminal fluid. |
| 1. | (A) is True but (R) is False. |
| 2. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
| 3. | (A) is False but (R) is True. |
| 4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |