In developing the cell theory, Virchow proposed the idea that cells come from pre existing cells. This was contradictory to the beliefs of most scientists at the time. Louis Pasteur provided proof of this when he performed an experiment with sterilized nutrient broth.
The broth in straight neck flasks grew bacteria, but the flasks with curved necks did not grow bacteria.
How are scientific theories formed?
A)
from the opinions of very educated people
B)
from one experiment of a famous scientist
from evidence gained by many experiments of many scientists
D)
ignoring any experimental evidence that does not fit the theory

it provides an alternative energy pathway for the reaction to proceed.

a catalyst is a substance that speeds up the rate of a chemical reaction but is not consumed during the course of the reaction.

catalysts increase the rate of reaction without being used up. they do this by lowering the activation energy needed. with a catalyst, more collisions result in a reaction, so the rate of reaction increases. different reactions need different catalysts.

a catalyst works by providing an alternative reaction pathway to the reaction product. the rate of the reaction is increased as this alternative route has a lower activation energy than the reaction route not mediated by the catalyst.

measured, submerged.