Glyphosate is a herbicide that looks a little like an amino acid. Remember
this as it is important later. I'm not sure of your educational background
so I'll start at the begining. Plants take carbon dioxide, water, and a
few other nutrients and make more complex substances. To do this takes a
series of chemical reactions. For the reactions to take place, energy must
be expended. Initially the sun provides the energy for the water and
carbon dioxide to make sugar and other high energy compounds. After that,
plants make more complex substances using the energy in the sugars and
other compounds (there are also other things like pH gradients and proton
fluxes, but I will ignore these).
Chemical reactions take a lot of energy. Some very complex compounds,
called enzymes help reduce the energy required to make the reaction work.
They do this in a number of ways, but basically, one compound binds to the
enzyme, the enzyme stretchs, bends, and/or reduces or increases charges,
such that a second compound can now easily combine with the first, with
much less energy required. The new compound that is formed is released and
then modified futher by another enzyme or used for something else by the
plant.