AP BIOLOGY

Detailed explanation-1: -Urea is filtered across the glomerulus and enters the proximal tubule. The concentration of urea in the ultrafiltrate is similar to plasma, so the amount of urea entering the proximal tubule is controlled by the GFR. In general, 30%–50% of the filtered load of urea is excreted.

Detailed explanation-2: -The urea and water are released from the liver cells to the bloodstream and transported to the kidneys where the blood is filtered and the urea is passed out of the body in the urine.

Detailed explanation-3: -Summary. Urea is a waste product of metabolism that is excreted by the kidneys in urine.

Detailed explanation-4: -On an average, 25−30 grams of urea is excreted out per day by a healthy individual.

Detailed explanation-5: -Urea is freely filtered by the glomerulus and then passively reabsorbed in both the proximal and distal nephrons.