Question

Question #bc898

Answer 1

Active transport is movement of ions & molecules against their concentration or electrochemical gradient i.e from lower concentration to the higher one.

Explanation:

As it would be bit tricky for the molecules & ions to escape from the area where they are in lower concentration and to get in the one with higher concentration. So, they definitely would need energy `(ATP)`. This required energy input is provided by mitochondria of cell.
Active transport basically require two things `to` carrier proteins and energy.

One of the best example of active transport is sodium-potassium pump that takes place in plasma membranes of all animal cells.

Video below gives an amazing elucidation of `Na^+"/"K^+` pump.

Other examples are:

• In small intestine, glucose is absorbed by active transport into villi so that it get it's way into blood stream and can be taken around the body.

• Proximal convoluted tubule of nephron reabsorbs all the useful molecules i.e glucose, amino acids and salts via active transport.

• Calcium pump use active transport etc...

`Note:`
Active transport has two types:

• Primary active transport `to` obtain energy directly as a result of breakdown of `ATP`.

• Secondary active transport `to` obtain energy from concentration gradient of driving ions and also from primary active transport.

Hope it helps...