In nutrient-rich environments (like your mouth), bacteria can use the provided amino acids to synthesize their proteins. however, should the environmental conditions change and become nutrient-poor, bacteria would need to synthesize their amino acids. they can do this using

citric acid cycle intermediates

Explanation:

Many citric acid cycle intermediates can be siphoned off and thus can be used to generate the amino acids. The intermediates which can provide carbon skeletons for the synthesis of the amino acids are oxaloacetate which helps in the formation of aspartate as well as asparagine; and alpha-ketoglutarate which helps in the formation of the glutamine, proline, as well as arginine.

giant impact theory - the moon was formed from the collision between earth and another mars-sized body.

colliding planetesimals hypothesis - the moon was formed from the same cloud of material as earth.

capture hypothesis - the moon was locked into orbit by earths gravity as it was passing by it.

accretion hypothesis - the moon was formed from collisions and combining of planetesimals.

i think this is right, if not and you know better let me know.