[thedoc (OP)]

JOHN CONDON  asked the Naked Scientists:
   
Do bacteria grow by breaking down and building up the cell wall or membrane?

Or do the building block components just get inserted into the wall? If the first idea is correct then presumably enzymes must be involved. If these 'breaking down' enzymes be isolated and synthesised to make antibiotics to 'dissolve' the bacteria wall/membrane.

This enzyme would be specific for each bacteria & would not lead to bacteria becoming resistant?

John Condon

What do you think?

[schneebfloob]

Bacterial cell walls are polymers of a molecule called peptidoglycan. One of the main modes of action by antibiotics is disrupting cell wall synthesis, by preventing the polymerization of peptidoglycan chains. This stops cell wall formation, and is of no use against pre-existing cells. The antibiotics that do this are called the beta-lactam antibiotics, and many are penicillin derivatives.

Bacteria have developed resistance to them by acquiring a gene encoding an enzyme called beta-lactamase. This targets and inhibits the antibiotics.

[Cindy Hang]

Bacteria usually grows in dark, moist, and warm places. It can form also in food or liquids left out to long. When people refer to bacteria growth it is actually about the amount of bacterium in a colony rather than the actual size of an individual bacterium increasing. Bacterium reproduce asexually through binary fission. This is when they basically just make a copy of their chromosome and then split. They reproduce sexually through conjunction. This is when they attach to one another using their pili, which are short hairlike structures on the outside of the cell.

Thanks a lot,
Cindy