Question

2. which of the following correctly identifies active transport?

Answer 1

Active transport is a phenomena of the movement of molecules move from a region of lower concentration to a region of higher concentration across a cell membrane. Osmosis follows the same scheme of movement of the molecules through the membrane. The difference is that diffusion does not need a membrane to transfer the molecules across.

Answer 2

Answer: 2) Active transport can be defined as the movement of molecules across a membrane from a lower concentration region to higher concentration region in the direction against a concentration gradient. Active transport spend cellular energy to achieve this movement.

The active transport is of two types namely primary active transport and secondary active transport. Primary active transport use ATP as a energy for the movement while secondary active transport uses electrochemical energy for their transport.

Answer: 3) Osmosis is the movement of solvent particles across a semi-permeable membrane from dilute solution in to a concentrated solution.

Diffusion is the movement of particle from area of higher concentration to lower concentration without any semi-permeable membrane. The overall effect is to equalize the concentration throughout the medium.