Write in brief how plants synthesize amino acids.

Explanation

`NH_4^(+)` is used to synthesize amino acids in plants. There are two main ways in which this can take place :
1) Reductive amination 2) Transamination
1) Reductive amination : In these processes, ammonia reacts with `alpha`-ketoglutaric acid and forms glutamic acid as indicated in the equation given below
`alpha`-ketoglutaric acid + `NH_4^(+) + NADPH underset("Dehydrogenase")overset("Glutanate")(rarr) "Glutamate " + H_2O + NADP`
2) Transamination : It involves the transfer of an amino group from an amino acid to the keto group of a keto acid. Glutamic acid is the main amino acid from which the transfer of `NH_2` the amino group, takes place and other amino acids are formed through transamination. The enzyme transaminase catalyses all such reactions. For example,
`underset("Amino-donor")(R_1-underset(NH_3^(+))underset(|)overset(H)overset(|)(C)-COO^(-))+underset("Amino-acceptor")(R_2-underset(O)underset(||)(C)-COO^(-))