Question

What is an example of active transport in the human body?

Answer 1

Hint: Active transport is the process in which molecules are moved across the cell membrane with the help of cellular energy. This kind of transport takes place from a lower to a higher concentration place for cellular energy. It takes place in the cells of the human to get the energy that is needed for performing various activities.

Complete answer:
Active transport is used by the cells for the accumulation of molecules that are required by the cell-like amino acids and glucose generally from the region of lower concentration to higher concentration. The transportation which is powered by adenosine triphosphate (ATP) is called primary active transport whereas the transport that uses electrochemical gradient is called secondary transport.

Primary transport is carried out by the transmembrane ATPase which is an enzyme that crosses the cell membrane which is mainly found in animal cells. This helps in maintaining the cell membrane potential by pumping 3 sodium ions out of the cell for every 2 potassium ions it moves into the cell. Secondary active transport is done through the electrochemical potential that is built up by the pumping of ions in and out of the cell. This potential is needed for providing energy for metabolism.

One of the best examples of active transport are:
a. Transportation of calcium ions out of the cells of the cardiac muscle cells.
b. Secretion of proteins like enzymes, antibodies and many other peptide hormones by cells.
c. Transportation of the amino acid taking place in between the intestinal lining of the human gut.

Note: Transmembrane proteins are those proteins that cross the cell membrane. They usually have one or more transmembrane domains that cross the membrane made of the lipid bilayer and the domain which binds with the ligands inside and outside of the membrane. The proteins help in the recognition of the molecules to be transported and pass in through the transmembrane.