Many different activated carriers that help cell metabolism

Many different activated carriers that help cell metabolism

ATP

In my last essay, I mentioned how enzyme catalyzed reactions, which is energetically unfavourable, occur in the cell. However, there is another way to promote energetically unfavourable reactions in the cell: ATP. ATP is one of the most famous activated carriers and promotes condensation reactions using its energy stored in the phosphoanhydride bond(because when ATP hydrolysis occurs ΔG is negative). This process occurs when it generates other activated carriers, or links subunits together  by bonds formed during the condensation reaction(and produces the nucleic acids, proteins and polysaccharides). 

NADPH and NADH

They carry energy in the form of hydride ions(two high energy electrons plus a proton). The difference between them is that they differ in conformation, which makes it possible to bind as substrates to different sets of enzymes. Thus, they have different rolls. NADH is used in catabolic reactions which occurs when the cell is synthesizing ATP. On the other hand, NADPH is needed in anabolic reactions. In other words, NADH acts as a oxidizing agent while NADPH acts as a reducing agent. Basically, inside the cell the ratio of NAD＋to NADH is kept high whereas the ratio of NADP＋to NADPH is kept low(for the reason above)

Acetyl CoA

This is also one of the activated carriers but i won’t explain it cuz i don’t know much about it!(but it was kind of surprising when i found out it is an activated carrier) it carries acetyl groups.

In activated carriers, the transferable group makes up only a small part of the molecule. the rest serves as a convenient handle facilitating the recognition of the carrier molecule by specific enzymes. This handle mostly contains a nucleotide, which may be a relic from an early stage of cell evolution(it is said the main catalysts for early life forms on earth were RNA molecules)