Excretory Products and Their Elimination MCQs for NEET — Zoology Questions with Answers

Urea formation occurs through the Ornithine cycle, also known as the urea cycle. The cycle converts ammonia, which is toxic to the body, into urea, which can be excreted in urine. This process primarily takes place in the liver.

The primary function of the loop of Henle in the kidney is the conservation of water. It creates a concentration gradient in the medulla of the kidney, which helps the body to reabsorb water and concentrate urine, thus conserving water.

The proboscis gland in Balanoglossus is associated with excretion. It plays a role in the removal of metabolic wastes from the body, functioning similarly to a primitive excretory system.

The appearance of albumin in the urine, a condition known as albuminuria, is most likely due to damage to the Malpighian corpuscles (glomeruli). The glomeruli are responsible for filtering blood, and damage to them can lead to the leakage of proteins like albumin into the urine.

The kidneys filter waste products from the blood while retaining essential constituents. Glucose and proteins are typically not lost in the urine. Glucose is reabsorbed in the proximal tubule, and proteins are usually too large to pass through the glomerular filter. Hence, their levels remain unchanged after the blood circulates through the kidneys.

The process of urine formation in the nephron includes three main mechanisms: ultrafiltration, reabsorption, and secretion. Ultrafiltration occurs in the glomerulus, reabsorption occurs primarily in the proximal tubule, and secretion happens in the distal tubule and collecting duct.

Deamination is the process by which amino acids are broken down in the body to release ammonia (NH4) and carbon dioxide (CO2). This process primarily occurs in the liver. The ammonia released is then converted into urea, which is less toxic and is excreted from the body via the kidneys.

Transamination is a process that occurs primarily in the liver. It involves the transfer of an amino group from one amino acid to a keto acid, forming a new amino acid and a new keto acid. This process is crucial for the synthesis of non-essential amino acids.

The solubility of substances in water can be ranked as follows: NH3 (ammonia) > urea > uric acid. Ammonia is highly soluble in water, followed by urea, and uric acid is the least soluble among the three.