All Free Biology MCQs with Answers

• A. Higher ionic concentration inside vacuoles
• B. Higher osmotic pressure of the cell vacuole
• C. Large number of vacuoles in a plant cell
• D. Both a and b

Explanation: Option D is correct.Higher ionic concentration means water does not leave the vacuole, and the higher osmotic pressure of the vacuole…

• A. Aldosterone
• B. Thyroxine
• C. ADH
• D. Cortisone

Explanation: As a general principle, Sodium-Ion Concentration in the body is maintained by the hormone Aldosterone.

• A. The ascending limb of the loop of gentle
• B. The collecting duct
• C. The descending limb of the loop of gentle
• D. The proximal convoluted tubule

Explanation: ADH receptors are present on the collecting duct and thus ADH hormone acts on the collecting duct cells.

• A. I
• B. II
• C. III
• D. IV
• E. V

Explanation: Urinary bladder is the part of the urinary system that temporarily stores urine and releases it when filled.

• A. Glomerulus and Bowman's Capsule
• B. Proximal and distal end
• C. Ascending and descending arm
• D. Loop of henle

Explanation: The Glomerulus and Bowman's capsule are sited of filtration in the nephron while ascending/descending loop of Henle carries out…

• A. Renal pelvis
• B. Hilus
• C. Medulla
• D. Pyramid

Explanation: The medial concave border of a kidney contains a notch known as hilus through which the renal artery enters and the renal vein and ureter…

• A. Renin
• B. Atrial­ natriuretic factor
• C. Alcohol
• D. Caffeine

Explanation: Blood pressure regulation is the main function of renin. It works together with angiotensin and aldosterone to manage the levels of sodium…

• A. Urea in tadpole and ammonia in adult frog
• B. Ammonia in tadpole and urea in adult frog
• C. Urea in both tadpole and adult frog
• D. Urea in tadpole and uric acid in adult frog

Explanation: Ammonia is highly soluble in water, so in aquatic animals e.g., tadpole of frog, the nitrogenous waste products are excreted in the form…

• A. No Supply of Water
• B. Sufficient Supply of Water
• C. Excess Supply of Water
• D. Restriced Supply of Water

Explanation: When supply of water to the body is restricted the water inside the body is conserved to compensate it and vice versa.

• A. Homeothermic organisms
• B. Hyperthermic organisms
• C. Poikilothermic organisms
• D. None of these

Explanation: Homeothermic organisms are those which maintain their body tempareture when exposed to changing surrounding temperature.

• A. Sweat - Temperature regulation
• B. Saliva - Sense of food taste
• C. Sebum - Sexual attraction
• D. Humerus - Hindleg

Explanation: Sweat is secreted by sweat glands of skin and helps in regulating body temperature.

• A. When someone drinks a large amount of water, ADH release is suppressed.
• B. Exposure to cold temperatures stimulates ADH release.
• C. An increase in glomerular blood flow stimulates formation of angiotensin II.
• D. During summer when the body loses a lot of water due to evaporation, the release of ADH is suppressed.

Explanation: Antidiuretic hormone (ADH) or vasopressin increases the reabsorption of water in the distal convoluted tubule, collecting tubules and…

• A. Anuria
• B. Deamination
• C. Uremia
• D. Oliguria

Explanation: Anuria is the medical term for the complete cessation of urine production by the kidneys, often resulting from severe kidney damage or…

• A. 99.0%
• B. 99.1%
• C. 99.5%
• D. Approximately 99.5%

Explanation: More than 99.5% water from filtrate is reabsorbed in human and mammalian kidney.

• A. Glomerulus
• B. Convoluted Tubule
• C. Loop of Henle
• D. Bowman's Capsule

Explanation: The correct answer is the glomerulus because it is the primary site of filtration within the nephron, making it particularly vulnerable to…

• A. Sweat - Temperature regulation
• B. Saliva - Sense of taste
• C. Sebum - Sexual attraction
• D. Humerus - Hindleg

Explanation: Sweat is secreted by sweat glands of skin and helps in regulating body temperature.

• A. Tendency to change with environmental changes
• B. Tendency to resist change and maintain stability
• C. Disturbance in regulatory control
• D. Use of plants and animal extracts in homeopathy

Explanation: Homoeostasis is the regulation, by an organism, of the chemical composition of its body fluids and other aspects of its internal…

• A. Flow of solvent (water) through a semipermeable membrane from a higher to a less concentrated solution
• B. Flow of solvent (water) through a semipermeable membrane from a less to a higher concentrated solution
• C. Flow of a solute through a semipermeable membrane
• D. Flow of water without a membrane

Explanation: Osmosis is the process by which water, the solvent, moves across a semipermeable membrane from an area of low solute concentration to an…

• A. Aldosterone
• B. Parathormone
• C. Anti-diuretic hormone
• D. Vasopressin

Explanation: Parathormone, or parathyroid hormone, is responsible for increasing the reabsorption of calcium ions in the nephron, particularly in the…

• A. An artificial kidney
• B. Filtering it within abdomen
• C. Both A and B
• D. Removing waste products and excess fluid from blood

Explanation: Dialysis serves the function of the kidneys when they fail by removing waste products, excess salts, and excess water from the blood.