Grade 11 : Biology - Excretion System (Set 6)

Question 1

Nitrogenous metabolic wastes generated from protein and nucleic acid catabolism differ significantly in toxicity, water solubility, and metabolic synthesis costs among animal taxa.

Which of the following correctly arranges the major nitrogenous wastes in decreasing order of toxicity and in increasing order of energy requirement for synthesis?

Accepted Answer

A) Toxicity: Ammonia > Urea > Uric acid; Energy: Uric acid > Urea > Ammonia

Answer

B) Toxicity: Uric acid > Urea > Ammonia; Energy: Ammonia > Urea > Uric acid

Answer

C) Toxicity: Urea > Ammonia > Uric acid; Energy: Urea > Uric acid > Ammonia

Answer

D) Toxicity: Ammonia > Uric acid > Urea; Energy: Uric acid > Ammonia > Urea

Question 2

Nephron Type X: Short loop of Henle extending only slightly into the outer medulla; constitutes ~85% of human nephrons; vasa recta is absent or highly reduced.
Nephron Type Y: Long loop of Henle extending deep into the inner medulla; constitutes ~15% of human nephrons; highly developed vasa recta present.

Based on the structural characteristics described above, identify Nephron Type X and Nephron Type Y respectively.

Accepted Answer

A) Cortical nephron, Juxtamedullary nephron

Answer

B) Juxtamedullary nephron, Cortical nephron

Answer

C) Medullary nephron, Glomerular nephron

Answer

D) Primary nephron, Secondary nephron

Question 3

In a human kidney physiology study, the pressures governing ultrafiltration in Bowman's capsule were measured as: Glomerular Hydrostatic Pressure (GHP) = 60 mmHg, Blood Colloidal Osmotic Pressure (BCOP) = 32 mmHg, and Capsular Hydrostatic Pressure (CHP) = 18 mmHg.

Calculate the Net Filtration Pressure (NFP) driving fluid into Bowman's space.

Accepted Answer

B) 10 mmHg

Answer

A) 28 mmHg

Answer

C) 50 mmHg

Answer

D) 42 mmHg

Question 4

Tubule Segment	Water Permeability	Solute Transport Properties	Primary Physiological Function
Segment A	High	Active reabsorption of $Na^+$, $K^+$, glucose	~70–80% electrolyte & water reabsorption
Segment B	High	Impermeable to salts	Passive water reabsorption (concentrates filtrate)
Segment C	Impermeable	Active/passive transport of $Na^+$, $Cl^-$	Dilution of filtrate (salt reabsorption)
Segment D	Variable (ADH dependent)	Conditional $Na^+$ reabsorption	Fine-tuning water & pH balance

Which sequence correctly identifies Segments A, B, C, and D of the renal tubule?

Accepted Answer

A) A: Proximal Convoluted Tubule, B: Descending limb of Henle's loop, C: Ascending limb of Henle's loop, D: Distal Convoluted Tubule

Answer

B) A: Distal Convoluted Tubule, B: Ascending limb of Henle's loop, C: Descending limb of Henle's loop, D: Proximal Convoluted Tubule

Answer

C) A: Proximal Convoluted Tubule, B: Ascending limb of Henle's loop, C: Descending limb of Henle's loop, D: Collecting Duct

Answer

D) A: Bowman's capsule, B: Proximal Convoluted Tubule, C: Loop of Henle, D: Collecting Duct

Question 5

As tubular fluid moves down the descending limb of Henle's loop, its osmolality progressively increases from 300 mOsmol/L at the cortex to 1200 mOsmol/L at the hairpin bend deep in the medulla.

What is the primary physical process causing this hypertonicity of filtrate in the descending limb?

Accepted Answer

B) Outward passive osmosis of water into the hyperosmotic medullary interstitium

Answer

A) Active transport of sodium ions out of the descending limb into the interstitium

Answer

C) Active secretion of urea and uric acid into the descending limb lumen

Answer

D) Passive diffusion of glucose from interstitial fluid into the tubular lumen

Question 6

Statement 1: Podocytes are specialized visceral epithelial cells surrounding the glomerular capillaries.
Statement 2: Slit pores or filtration slits are micro-gaps formed between neighboring podocyte foot processes (pedicels).
Statement 3: Plasma proteins with molecular weight greater than 70 kDa readily pass through the filtration membrane into the capsular space.

Which of the statements given above are CORRECT regarding ultrafiltration in the mammalian kidney?

Accepted Answer

A) Statements 1 and 2 only

Answer

B) Statements 2 and 3 only

Answer

C) Statement 1 only

Answer

D) Statements 1, 2, and 3

Question 7

Consider the following key biological events involved in the physiological regulation of blood pressure and renal hemodynamics:
1. Juxtaglomerular (JG) cells release Renin.
2. Renin converts Angiotensinogen into Angiotensin I.
3. ACE converts Angiotensin I into Angiotensin II.
4. Angiotensin II triggers Aldosterone release from the adrenal cortex.
5. Reabsorption of $Na^+$ and water increases in DCT/Collecting Duct.

Which of the following represents the correct step-by-step cascade of the RAAS mechanism triggered by a fall in GFR?

Accepted Answer

B) $1 \rightarrow 2 \rightarrow 3 \rightarrow 4 \rightarrow 5$

Answer

A) $2 \rightarrow 1 \rightarrow 4 \rightarrow 3 \rightarrow 5$

Answer

C) $3 \rightarrow 1 \rightarrow 2 \rightarrow 5 \rightarrow 4$

Answer

D) $1 \rightarrow 3 \rightarrow 2 \rightarrow 4 \rightarrow 5$

Question 8

An individual experiences excessive sweating during intense athletic activity without water intake, leading to dehydration and increased plasma osmolality.

How do osmoreceptors and the neurohypophysis respond to restore fluid homeostasis?

Accepted Answer

A) Osmoreceptors trigger ADH release, increasing water permeability of DCT and Collecting Duct to produce hypertonic urine.

Answer

B) Osmoreceptors inhibit ADH release, decreasing water permeability of PCT to produce hypotonic urine.

Answer

C) Osmoreceptors stimulate ANF release, inducing vasodilation and increased excretion of dilute urine.

Answer

D) Osmoreceptors trigger Renin inhibition, decreasing sodium retention in the loop of Henle.

Question 9

An increase in blood flow to the atria of the heart causes stretching of cardiac atrial walls, stimulating the release of Atrial Natriuretic Factor (ANF).

How does ANF act as a physiological antagonist (check) to the Renin-Angiotensin System?

Accepted Answer

B) By causing vasodilation and inhibiting the secretion of Renin from Juxtaglomerular cells.

Answer

A) By causing systemic vasoconstriction and enhancing aldosterone release from the adrenal gland.

Answer

C) By increasing sodium reabsorption in the ascending loop of Henle to raise blood volume.

Answer

D) By stimulating ADH release from the neurohypophysis to concentrate filtrate.

Question 10

Location: Zone of cellular contact where the Distal Convoluted Tubule passes adjacent to the Afferent Arteriole of the same nephron.

Which two specialized cellular modifications form the functional Juxtaglomerular Apparatus (JGA)?

Accepted Answer

A) Macula densa cells of DCT and Juxtaglomerular (JG) cells of afferent arteriole

Answer

B) Podocytes of Bowman's capsule and Endothelial cells of glomerulus

Answer

C) Intercalated cells of collecting duct and Chief cells of loop of Henle

Answer

D) Mesangial cells and Kupffer cells of hepatic sinusoids

Question 11

Which specific ionic species are actively secreted into tubular filtrate by PCT and DCT epithelial cells to maintain systemic pH and acid-base equilibrium?

Accepted Answer

A) Hydrogen ions ($H^+$), Potassium ions ($K^+$), and Ammonia ($NH_3$)

Answer

B) Sodium ions ($Na^+$) and Bicarbonate ions ($HCO_3^-$)

Answer

C) Calcium ions ($Ca^{2+}$) and Chloride ions ($Cl^-$)

Answer

D) Glucose, Amino acids, and $HCO_3^-$

Question 12

The ascending limb of Henle's loop is impermeable to water but actively transports NaCl into the surrounding medullary interstitial fluid.

What happens to the osmotic concentration of filtrate as it ascends towards the distal convoluted tubule?

Accepted Answer

C) It becomes progressively hypotonic because electrolytes are removed while water stays behind.

Answer

A) It becomes hypertonic relative to blood plasma (1200 mOsmol/L).

Answer

B) Its osmolality remains strictly constant at 300 mOsmol/L.

Answer

D) It undergoes complete solute precipitation forming kidney stones.

Question 13

Under resting physiological conditions, human lungs continuously eliminate metabolic carbon dioxide ($CO_2$) at a rate of approximately 200 mL/min.

Calculate the total volume of $CO_2$ expelled by the lungs in a 1 -hour period.

Accepted Answer

C) 12.0 Litres

Answer

A) 1.2 Litres

Answer

B) 2.0 Litres

Answer

D) 120.0 Litres

Question 14

In hemodialysis for renal failure patients, arterial blood is pumped through a dialyzer containing cellophane tubes immersed in dialyzing fluid.

How does the chemical composition of dialyzing fluid compare with normal blood plasma?

Accepted Answer

A) It has an identical solute concentration to plasma, except that it completely lacks nitrogenous wastes.

Answer

B) It contains higher urea and uric acid concentration than plasma to draw solutes via active transport.

Answer

C) It is entirely hypertonic distilled water containing zero electrolytes.

Answer

D) It contains elevated concentrations of plasma proteins to increase oncotic pressure.

Question 15

A patient exhibits severe sharp lumbar back pain radiating to the groin, hematuria, and painful micturition. Clinical diagnostics reveal insoluble micro-crystalline masses lodged in the renal pelvis.

Identify this renal pathology and the most common chemical component of these kidney deposits.

Accepted Answer

B) Renal Calculi, composed primarily of Calcium Oxalates

Answer

A) Uremia, caused by excessive glucose crystals

Answer

C) Glomerulonephritis, caused by bacterial immune complexes

Answer

D) Diabetes Insipidus, caused by urea precipitation

Question 16

Which clinical condition is defined by the toxic accumulation of high concentrations of urea in the blood due to kidney failure?

Accepted Answer

A) Uremia

Answer

B) Glycosuria

Answer

C) Ketonuria

Answer

D) Glomerulonephritis

Question 17

Excretory Structures:
1. Protonephridia (Flame cells)
2. Nephridia
3. Malpighian tubules
4. Antennal glands (Green glands)

Which option correctly matches structures 1–4 with their respective animal groups?

Accepted Answer

A) 1: Platyhelminthes, 2: Annelids, 3: Cockroaches, 4: Crustaceans

Answer

B) 1: Annelids, 2: Platyhelminthes, 3: Crustaceans, 4: Cockroaches

Answer

C) 1: Cockroaches, 2: Crustaceans, 3: Platyhelminthes, 4: Annelids

Answer

D) 1: Crustaceans, 2: Cockroaches, 3: Annelids, 4: Platyhelminthes

Question 18

Statement I: Sweat produced by sweat glands is a watery fluid containing NaCl, small amounts of urea, and lactic acid.
Statement II: Sebaceous glands eliminate excess lipids, sterols, hydrocarbons, and waxes through sebum output.

Which evaluation of the above statements regarding human integumentary excretion is correct?

Accepted Answer

C) Both Statement I and Statement II are correct.

Answer

A) Statement I is correct, but Statement II is incorrect.

Answer

B) Statement II is correct, but Statement I is incorrect.

Answer

D) Both Statement I and Statement II are incorrect.

Question 19

Ingestion of ethyl alcohol (ethanol) chemically suppresses the release of Antidiuretic Hormone (ADH) from the posterior pituitary gland.

What direct physiological outcome does alcohol consumption have on urinary output and urine concentration?

Accepted Answer

A) Diuresis (increased urine volume) with low urine osmolality (dilute urine)

Answer

B) Oliguria (decreased urine volume) with high urine osmolality (concentrated urine)

Answer

C) Complete cessation of urine formation (anuria)

Answer

D) Increased excretion of glucose and plasma proteins

Question 20

Which mineralocorticoid hormone acts specifically on the Distal Convoluted Tubule (DCT) to stimulate active reabsorption of $Na^+$ ions and secretion of $K^+$ ions?

Accepted Answer

C) Aldosterone

Answer

A) Antidiuretic Hormone (ADH)

Answer

B) Atrial Natriuretic Factor (ANF)

Answer

D) Parathyroid Hormone (PTH)

Grade 11 : Biology - Excretion System (Set 6)