Antibiotics kill bacteria, not viruses

0:00Many people think antibiotics cure a cold. Do they?

0:05An antibiotic is a medicine that kills bacteria or stops them from growing.

0:10A bacterium is a tiny living cell. Some bacteria can make us ill.

0:16Like all cells, it has a cell membrane. Most bacteria also have a tough cell wall around it.

0:24Our own cells have a nucleus and a cell membrane, but no cell wall.

0:31One antibiotic, penicillin, was discovered by Alexander Fleming in 1928.

0:38Penicillin attacks something bacteria have and our cells lack: the cell wall.

0:45It stops the bacterium from building its wall, so the wall grows weak, the cell bursts and the bacterium dies.

0:53Our cells have no cell wall, so penicillin has nothing there to attack.

0:59A virus is not a cell, so it has no cell wall. This drawing is not to scale: real viruses are much smaller.

1:08It gets inside one of our cells and makes that cell build copies of the virus.

1:14Penicillin finds no cell wall to attack, and the virus is hidden inside our own cell.

1:20Colds and flu are caused by viruses, so antibiotics cannot cure them.

1:26Antibiotics kill bacteria, but they do not work on viruses, so they cannot cure a cold.