Two paicles have same diameter. The one which will pass easily through glomerular membrane has ?

Ans. is 'a' i.e., Positive chargeThe filtration surface is a three-layered structure : - i) Glomerular capillary endothelium; ii) The basement membrane (Basal lamina); and iii) Visceral epithelium of Bowman's capsule with their foot process (Podocytes).However, even the three layers put together do not provide an adequate structural basis for the degree of sieving achieved during filtration.The fenestration in the endothelium are 50-100 nm in diameter, and the slits between the foot process of epithelial cells (podocytes) are 25 nm wide.That leaves only the basement membrane to account for the selectivity and the filtration function of the glomerular membrane.Basement membrane contains hydrated channels approximately 6 nm wide.A fuher functional barrier in basement membrane is added by the fact that basement membrane glycoproteins are strongly negatively charged.That is why filtration surface is almost impermeable to plasma proteins which are negatively charged, e.g., albumin (size 7 nm).The passage of neutral or positively charged molecules of comparable diameter is not so difficult.Ultimately, molecules less than 4 nm is diameter are freely filtered while molecules larger than 8 nm are not filtered atall and the molecules between 4-8 nm diameter are filtered with difficulty which increases propoionately with size.