Refer the given figure of nephron.

Identify A, B, C and D and select the correct option regarding them

• A-Glomerulus -a tuft of capillaries formed by afferent arteriole.

• B-PCT-reabsorption of HCO₃ and selective secretion of H and K⁺ occurs here.

• C-DCT-almost all glucose, amino acids, water, Na, K and uric acid are absorbed here.

• D-collecting duct-extends from the cortex of the kidney to the inner parts of medulla. Large amount of water is secreted in this region.

Which of the following is true for excretion in humans?

• Glucose and amino acids are reabsorbed in PCT by simple diffusion.

• OCT is impermeable to water.

• Or an average, 25-30 gm of urea is excreted out per day.

• Maximum reabsorption occurs in the loop of Henle.

Assertion: In proximal convoluted tubule glomerular filtrate becomes hypertonic to blood plasma.

Reason: HCO₃^- is absorbed only in the proximal convoluted tubule.

• 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 : While on going down the loop of Henle, the filtrate becomes hypotonic.

Reason : The descending limb of loop of Henle is impermeable to both water and electrolytes.

• 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 is correct regarding the excretion

• Large amount of water from renal filtrate is reabsorbed in DCT and a less amount is reabsorbed by PCT.

• The descending limb of loop of Henle is completely impermeable to salts.

• Malpighian corpuscle is found in medulla region of kidney.

• The colour of urine is pale yellow and is slightly alkaline in nature.

Assertion : Secreting hypotonic urine is effective in reducing urinary loss of water.

Reason : Hypotonic urine is more concentrated and higher in osmotic pressure than the blood.

• 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 statements is correct with respect to salt water balance inside the body of living organisms?

• when water is not available camels do not produce urine but store urea in tissues.

• Salmon fish excretes lot of stored salt through gill membrane when in fresh water

• Paramecium discharges concentrated salt solution by contractile vacuoles

• The body fluids of fresh water animals are generally hypotonic to surrounding water

A person passes much urine and drinks much water but his blood glucose level is normal. This condition may be the result of:

• a reduction in insulin secretion from pancreas

• a reduction in vasopressin secretion from posterior pituitary

• a fall in the glucose concentration in urine

• an increase in secretion of glucagon

The amount of liquid filtered by glomeruli of kidney in 24 hours period is

• 170 L

• 100 L

• 200-250 cc

• 500-1000 cc

Average pH of human urine is :

• 6.0

• 9.0

• 3.0

• 7.0