Question

Which of the following characteristics best determines the composition of the initial filtrate produced in the nephron?

Group of answer choices

All molecules freely enter the nephron

Only wastes enter the nephron

Only small molecules enter the nephron

Only water enters the nephron

Only large molecules enter the nephron

Answer 1

Only small molecules enter the nephron, if I need to choose only one option.

If more than one is correct then, only small molecules enter the nephron & only water enters the nephron will I choose.

EXPLANATION

The initial filtrate produced in the nephron is from the glomerular filtration. It is a passive process. The filtration is based on the size of the molecule. Here, the water and solutes of lower size is filtered into the nephron.

From the options given,

All molecules freely enter the nephron is not correct so this statement is wrong.

Only waste enter the nephron is also not correct. The solutes of lower size and water enters freely and some of them are reabsorbed. So this statement is also false.

Only water enters the nephron is also not right because other solutes are also being filtered and being added as initial filtrate in nephron. So this statement is also wrong.

Large molecules are not filtered as it cannot pass through glomerular membrane. So this statement is also wrong.

So from the options given, in my opinion most appropriate one is the only small molecules enter the nephron.

If more than one correct answer is there. Then the answer would be only small molecules enter the nephron & only water enters the nephron.