Question

What is the difference between NADPH and NADH?

Answer 1

Hint: NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate) are the foremost abundant kinds of coenzymes inside the cell, which are used as electron and hydrogen carriers. NADH and NADPH are the reduced kinds of NAD and NADP, respectively. Though NADH and NADPH are structurally more similar, they differ by their role within the cell. The foremost difference between NADH and NADPH is that NADH is used in respiration whereas NADPH is used in photosynthesis. NADH is produced in glycolysis and Krebs cycle and is used within the electron transport chain to provide ATP via biological processes. NADPH is produced within the chemical reaction of photosynthesis and is used within the Calvin cycle to assimilate $C{O}_2$

Complete answer:
NAD, is altogether living cells, where it functions as a coenzyme. It exists either in an oxidized form $NA{D}^{+}$, which can accept an atom (i.e., a proton), or a reduced form NADH, which can donate an atom.
$NAD{P}^{+}$ is a uniform molecule with an identical function, differing from $NA{D}^{+}$, therein it contains an extra phosphate group. The oxidized form is $NAD{P}^{+}$ and the reduced form is NADPH.
The NADH molecule contains two phosphate groups linked by an oxygen molecule. Every phosphate group joins a five-carbon ribose sugar. One of these successively links to an adenine molecule, while the other links to a nicotinamide molecule. The transition from $NAD{P}^{+}$ to NADH occurs specifically at the nitrogen molecule within the ring structure of nicotinamide.
NADH takes part in metabolism by accepting and donating electrons, with the energy driving this flowing from the cellular acid cycle or tricarboxylic acid (TCA) cycle. This electron transport occurs in cellular mitochondrial membranes. The NADPH molecule also contains two phosphate groups linked by an oxygen molecule. As in the NADH molecule, each phosphate group joins a five-carbon ribose sugar. One of these successively links to an adenine molecule, while the other links to a nicotinamide molecule. Unlike NADH, the same five-carbon ribose sugar that joins adenine carries a second phosphate group, for an entire of three phosphate groups in total. The transition from $NAD{P}^{+}$ to NADPH again occurs at the nitrogen molecule within the ring structure of nicotinamide.
NADPH's main job is participating within the synthesis of carbohydrates in photosynthetic organisms, like plants. It helps power the Calvin cycle. It also has antioxidant functions.

Note:
In addition to the direct contributions to cellular metabolism described above, both NADH and NADPH may participate in other important physiological processes, including mitochondrial functions, calcium regulation, antioxidation and its counterpart (the generation of oxidative stress), natural phenomenon, immune functions, the aging process and necrobiosis.