Explanation

• T₃ (Triiodothyronine) and T₄ (Thyroxine) are thyroid hormones.
• They are produced in the thyroid gland.
• They are formed by iodination of the amino acid tyrosine.
• Iodinated tyrosine molecules (iodotyrosine) combine to form T₃ and T₄.
• Dopamine and GABA are neurotransmitters, not thyroid hormone precursors.

Last updated question 17-02-2026

Explanation

Active transport is a critical process in the nephron used to reabsorb solutes against their concentration gradients

Proximal Tubule:

This is the primary site of active transport, where approximately 65–70% of filtered sodium is reabsorbed via the Na⁺/K⁺-ATPase pump.

It also uses secondary active transport to reabsorb 100% of filtered glucose and amino acids.

Last updated question 17-02-2026

Explanation

•  Mammary glands are modified sweat glands.
•  They produce milk for offspring.
•  Structurally, they retain sweat gland features.
•  They are present in mammals only.
•  Hormones regulate their secretion.

Last updated question 17-02-2026

Explanation

 Sodium is most heavily reabsorbed in the proximal tubule of the kidney,

Accounts for approximately 65% to 70% of the total filtered sodium. 

Last updated question 17-02-2026

Explanation

Humans cannot synthesize essential fatty acids, particularly Omega-3 (like alpha-linolenic acid) and Omega-6 fatty acids.

They must be obtained from the diet (e.g., fish, flaxseed, walnuts).

Palmitic, oleic, and stearic acids can be produced in the human body

Last updated 17-02-2026

Explanation

The kidney is the primary organ responsible for filtering blood in the human body.

Each kidney contains approximately one million microscopic units called nephrons

They actively remove metabolic wastes (such as urea and creatinine)

Explanation

Explanation

Tensile strength refers to a material’s ability to resist being pulled apart.

Bones have collagen fibers that provide high tensile strength.

This allows bones to withstand forces that try to stretch or bend them.

Explanation

Collagen is a structural protein that forms strong fibers in bones.

It provides tensile strength and flexibility, preventing bones from breaking easily.

Collagen works together with calcium phosphate to maintain bone rigidity.

Loss of collagen with age can lead to brittle bones and osteoporosis.

Explanation

Diabetes mellitus is a metabolic disorder where the body cannot properly regulate blood glucose.

It occurs due to insufficient insulin production or poor insulin response.

High blood sugar over time can damage organs like the heart, kidneys, and eyes.

Symptoms include frequent urination, excessive thirst, and unexplained weight loss.