Amino Acid Synthesis

Question 1

where is nitrogen found?

Answer 1

nucleic acids/nucleotides 
proteins/amino acids
cofactors
small hormones
neurotransmitters 
pigments 
defense chemicals

Question 2

most bio-useful form of nitrogen

Answer 2

ammonia

Question 3

nitrogenase complex

Answer 3

enzyme that catalyzes the nitrogen fixation reaction
present in some archea, plants, and animals
made up of dinitrogenase reductase and dinitrogenase (2 copies of each)

Question 4

dinitrogenase reductase

Answer 4

provides high energy electrons as reducing power
each is a homodimer bridged by a [4Fe-4S] cluster
each subunit has an ATP binding site

Question 5

dinitrogenase

Answer 5

uses high-energy electrons to reduce nitrogen to ammonia 
each module is an alpha/beta heterodimer with a P cluster and FeMo cofactor

Question 6

how many electrons are required for each nitrogen molecule fixed?

Answer 6

8 (6 for generation of 2 ammonia molecules, 2 for generation of a hydrogen molecule)

Question 7

how many ATP are hydrolyzed for every nitrogen molecule fixed?

Answer 7

16

ATP hydrolysis drives the transfer of electrons from the reductase complex to dinitrogenase!

Question 8

how many ATP are hydrolyzed for every electron transferred?

Answer 8

2

Question 9

flow of electrons in the nitrogenase complex

Answer 9

pyruvate → ferredoxin → dinitrogenase reductase → P cluster of dinitrogenase → FeMo center (where nitrogen is reduced to ammonia)