Question

Blood plasma contains proteins but glomerular filtrate does not. Why does this difference in composition occur?

(a) Blood osmotic pressure is maintained by the presence of plasma proteins

(b) Proteins are actively transported from the kidney tubule back into the blood capillaries

(c) Proteins cannot pass through the membranes of the glomerular capillaries.

(d) There is a high hydrostatic pressure in the blood within the glomerular capillaries.

Answer 1

Correct option: (c) Proteins cannot pass through the membranes of the glomerular capillaries.

Explanation:

The filtration slits in the epithelium of the renal corpuscle are about 25nm wide, too small for most of the proteins to pass through. Only small solute molecules like glucose may be filtered out.