The energy needed by a system to initiate a process is called as the activation energy. It describes the minimum energy which must be available to a chemical system with potential reactants to result in a chemical reaction. Hope this answers the question.
In photosynthesis, an electron carrier of the light cycles is the nicotinamide adenine dinucleotide phosphate or NADP. This is the oxidized form, because the reduced form of this carrier has the extra H (NADPH). This is somehow related to the electron carrier called nicotinamide adenine dinucleotide or NAD (minus the phosphate).
Cytosine, thiamine, uracil are prima de bases. ade dune and guanche are purine bases.
Answer: Exergonic reaction; Endergonic reaction
In coupled reactions, the energy released by an exergonic reaction is used to drive an endergonic reaction. ATP breakdown is often coupled to cellular reactions that require an input of energy.
Explanation:
Cellular reactions include Exergonic and endergonic reactions. An exergonic reaction is one that occurs spontaneously and brings about the release of energy (in form of ATP). On the other hand, an endergonic reaction proceeds only with the input of energy.
Thus, exergonic reactions are usually coupled to endergonic reactions