<prompt> Glucose is absorbed in the intestine along with-1 Na2 Na1K2 K  <response>: Ans. is a i.e., 1 Na In secondary active transport, the energy is derived from the store which has been created orginally by primary active transport. Secondary active transport represents a combination of primary active transport and facilitated diffusion. It is exemplified by glucose transport across intestinal mucosal epithelial cells, the NaK pump operates at the basolateral border of the cell and maintains intracellular concentration of Na very low. The low intracellular Na concentration provides the necessory concentration gradient for Na to diffuse in passively at the luminal border through facilitated cotransport with glucose. Thus, the NaK pump NaK ATPase indirectly powers the movement of glucose into the cell, and glucose can move in against a concentration gradient so long as Na diffuses in along a concentration gradient. It is important to know that at luminal border, Na is transported by facilitated diffusion as it diffuses along a concentration gradient while the glucose is transported actively against a concentration gradient and the energy is provided by NaK ATPase at basolateral border - So, secondary active transport is a combination of active transport glucose transport against concentration gradient and facilitated diffusion Na transport along concentration gradient by carrier protein. 