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In organic chemistry, a lactol is a functional group which is the cyclic equivalent of a hemiacetal (−CH(OH)O−) or a hemiketal (>C(OH)O−). The compound is formed by the intramolecular , nucleophilic addition of a hydroxyl group ( −OH ) to the carbonyl group ( C=O ) of an aldehyde ( −CH=O ) or a ketone ( >C=O ).
Right: a lactol of fructose, a cyclic hemiketal. Hemiacetals commonly exist in nature as aldoses such as glucose , and hemiketals commonly exist in nature as ketoses such as fructose . The favorability of the formation of a strain-free six-membered ring and the electrophilicity of an aldehyde combine to strongly favor the acetal form.
In cyclic photophosphorylation, cytochrome b 6 f uses electrons and energy from PSI to create more ATP and to stop the production of NADPH. Cyclic phosphorylation is important to create ATP and maintain NADPH in the right proportion for the light-independent reactions. The net-reaction of all light-dependent reactions in oxygenic photosynthesis ...
Section of a cell wall; hemicellulose in green. Based on the structural difference, like backbone linkages and side groups, as well as other factors, like abundance and distributions in plants, hemicelluloses can be categorized into four groups as following: [4] 1) xylans, 2) mannans; 3) mixed linkage β-glucans; 4) xyloglucans.
It is a common method to make amines and is widely used in green chemistry since it can be done catalytically in one-pot under mild conditions. In biochemistry, dehydrogenase enzymes use reductive amination to produce the amino acid glutamate. Additionally, there is ongoing research on alternative synthesis mechanisms with various metal ...
Following the Green–Davies–Mingos rules, since butadiene is an open π-ligand of even hapticity, nucleophilic attack will occur at one of the terminal positions of the π-system. This occurs because the LUMO of butadiene has larger lobes on the ends rather than the internal positions.
Lactones are usually named according to the precursor acid molecule (aceto = 2 carbon atoms, propio = 3, butyro = 4, valero = 5, capro = 6, etc.), with a -lactone suffix and a Greek letter prefix that specifies the number of carbon atoms in the heterocycle — that is, the distance between the relevant -OH and the -COOH groups along said backbone.
For instance, green light is not strongly adsorbed by mesophyll cells and can preferentially excite bundle sheath cells, or vice versa for blue light. [14] Because bundle sheaths are surrounded by mesophyll, light harvesting in the mesophyll will reduce the light available to reach BS cells.