Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Many amphibians excrete mainly ammonia when they are aquatic tadpoles and switch largely to urea excretion when they become land dwelling adults. |
Reason (R): | The main disadvantage of urea is its energy cost and the main advantage is its low toxicity. |
In the light of the above statements choose the correct answer from the options given below
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. |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Excreting uric acid in birds and reptiles with shelled eggs conveys a selective advantage. |
Reason (R): | Uric acid is more energetically expensive than urea. |
In the light of the above statements choose the correct answer from the options given below:
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. |
Assertion (A): | The filtration step common to other excretory systems in Malpighian tubules is absent. |
Reason (R): | Malpighian tubules in insects serve in excretion and osmoregulation. |
In the light of the above statements choose the correct answer from the options given below
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. |
Assertion (A): | Juxtamedullary nephrons are key adaptation for water conservation in mammals. |
Reason (R): | Juxtamedullary nephrons constitute about 85% of all nephrons in the mammalian kidney. |
In the light of the above statements choose the correct answer from the options given below:
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. |
Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R):
Assertion (A): | Anti diuretic hormone release is increased when blood osmolarity increases such as after eating salty foods or losing water through sweating. |
Reason (R): | ADH temporarily decreases the number of aquaporins inserted in the membranes of collecting duct cells. |
In the light of the above statements choose the correct answer from the options given below:
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. |
Which area actually secretes renin into the blood?
1. macula densa | 2. juxtaglomerular apparatus |
3. juxtaglomerular cells | 4. cortical nephron |
What adaptation would be seen in the kidneys of a mammal living in desert when compared to the kidneys in aquatic mammals?
1. | A higher percentage of cortical nephrons with short loop of Henle extending slightly into the medulla |
2. | A higher percentage of cortical nephrons with long loop of Henle extending deep into the medulla |
3. | A higher percentage of juxtamedullary nephrons with long loop of Henle extending deep into the medulla |
4. | Presence of only juxtamedullary nephrons with long loop of Henle extending deep into the medulla |
Refer the given figure of nephron.
Identify A, B, C, and D and select the correct option regarding them.
1. | A - Glomerulus - a tuft of capillaries formed by afferent arteriole. |
2. | B - PCT- reabsorption of \(HCO^-_3\) and selective secretion of H+ and K+ occurs here. |
3. | C - DCT- almost all glucose, amino acids, water, Na+, K+, and uric acid are absorbed here. |
4. | D - collecting duct - extends from the cortex of the kidney to the inner parts of the medulla; a large amount of water is secreted in this region. |
The hormone produced by the adrenal cortex, when stimulated by angiotensin II, that causes increased sodium and water reabsorption in the distal convoluted tubules, is:
1. renin | 2. aldosterone |
3. antidiuretic hormone | 4. cortisol |
Specialized smooth muscle cells mainly in the walls of the afferent arterioles called the Juxtaglomerular cells secrete:
1. ADH | 2. angiotensin |
3. aldosterone | 4. renin |