In which of the following nephron structures does reabsorption of organic substrates such as glucose and amino acids primarily occur?

Identify the primary site of organic substrate reabsorption: The proximal convoluted tubule (PCT) is the main site where the majority of reabsorption occurs. It has specialized cells with microvilli that increase surface area for efficient reabsorption of organic molecules such as glucose and amino acids.

Compare with other nephron structures: The loop of Henle primarily concentrates urine by reabsorbing water and salts, the distal convoluted tubule fine-tunes ion balance and pH, and the collecting duct adjusts water reabsorption based on hormonal signals. None of these structures are primarily responsible for reabsorbing organic substrates like glucose and amino acids.