Question

The yellow colour of urine is due to the presence of (a) urea (b) uric acid (c) urochrome (d) bilirubln.

Short answer

The yellow color of urine is due to the presence of (c) urochrome.

Step-by-step solution

Identify the cause of the yellow color in urine

To identify the chemical responsible for the yellow color of urine, one should know the relevant metabolic products excreted by the kidneys. Urea is a colorless compound, uric acid is generally associated with gout and not the color of urine, bilirubin is a yellow compound but is related to the liver and not directly responsible for the urine's yellow tint. Urochrome, however, is a pigment that is indeed responsible for the yellow color of urine. It is a breakdown product of hemoglobin from destroyed red blood cells and is excreted by the kidneys.

Key concepts

Urochrome

The vibrant yellow hue of urine is primarily attributed to a pigment known as urochrome. This substance originates from the natural breakdown of hemoglobin, the protein that carries oxygen in red blood cells. As red blood cells age and are decommissioned, hemoglobin is decomposed, and one of the resulting components is urochrome.

Discovered in the early 20th century, urochrome is continually produced and is soluble in water, which means it can be easily filtered out by the kidneys and excreted in the urine. The intensity of the yellow color depends on the concentration of urochrome, which can be influenced by factors such as hydration levels; less water intake can lead to darker yellow urine, indicating a higher concentration of urochrome and other waste products.

Urinary System

The urinary system plays a crucial role in maintaining the body's homeostasis, including the regulation of electrolyte balance, blood pressure, and the removal of waste products. It consists of the kidneys, ureters, bladder, and urethra.

The kidneys are the filtration units, where blood is purified and waste extracts are converted into urine. Ureters are tubular structures that carry urine from the kidneys to the bladder, where it is stored until it can be excreted through the urethra. This entire system works seamlessly to ensure that metabolic wastes like urea, uric acid, and excess salts are effectively removed, with urochrome being a visible indicator of this excretory process.

Metabolic Products

Metabolic products are the various substances produced and consumed during metabolism, the chemical processes that are vital to an organism's survival. In the context of urine color, these products include waste materials that result from the breakdown of proteins, nucleic acids, and other substances within the body.

Waste Metabolites

Among these metabolic products, urea and uric acid are significant. Urea is formed in the liver as a byproduct of protein metabolism and is a major component of urine. It is colorless but contributes to the solute load kidneys need to filter. Uric acid, resulting from nucleic acid metabolism, is usually a sign of the body's ability to process purines, and abnormal levels can lead to conditions like gout or kidney stones. Both are efficiently eliminated by the kidneys to maintain health.

Kidney Function

Kidneys are sophisticated organs that perform several functions essential for keeping the body's internal environment stable. One of their primary tasks is to filter and remove waste products from the blood, which includes the regulation of urochrome levels.

Filtration and Excretion

The kidneys adjust the volume and concentration of urine according to the body's needs, conserving water when dehydrated and expelling excess when overhydrated. They interact closely with other systems such as the cardiovascular system to maintain blood pressure and the skeletal system for calcium balance. Proper kidney function ensures that substances like urochrome are excreted in correct amounts, reflecting in the urine's color and contributing to the detection of various metabolic and renal diseases.