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Gadolinium is the chemical element with atomic number 64 and symbol . It is a lanthanide. The ion has seven unpaired 4f electrons, giving it strong paramagnetism. This connects atomic electron configuration with magnetic behavior and with the effect of coordinated gadolinium on nearby nuclear-spin relaxation.[ref]
Neptunium is the chemical element with atomic number 93. Its isotope neptunium-239 occurs between uranium-239 and plutonium-239 in a neutron-capture and beta decay production chain.
Antimony is the chemical element with atomic number 51 and symbol . It is a metalloid. Its common oxidation states include and . Elemental antimony is brittle, while its compounds and alloys have distinct materials applications; potassium antimony tartrate is an example of a coordination compound rather than the free element.[ref]
Malonate is the dianion of malonic acid, with two carboxylate groups separated by one methylene group. Its three-carbon skeleton resembles part of the four-carbon skeleton of succinate.
Malonate is a classical inhibitor of succinate dehydrogenase: structural similarity allows binding without the normal substrate transformation. The example illustrates how an enzyme inhibitor can probe the contribution of a particular reaction to a metabolic pathway.
Ubiquinol is the reduced form of ubiquinone. Its quinone headgroup has accepted two electrons and two protons, while its hydrophobic side chain anchors it in a cell membrane.
In the mitochondrial respiratory chain, diffusion of ubiquinol within the membrane transfers reducing equivalents between protein complexes. Oxidation back to ubiquinone releases the carried electrons and protons through a controlled sequence of steps.
Flavin adenine dinucleotide is a redox coenzyme with a flavin ring system linked to an adenine-containing nucleotide unit. Reduction of the flavin gives FADH2.
In succinate dehydrogenase, an enzyme-bound flavin accepts reducing equivalents during conversion of succinate to fumarate. The flavin is reoxidized through the respiratory electron-transfer machinery, connecting a carbon-metabolism reaction with the mitochondrial respiratory chain.
Fumarate is the dianion of fumaric acid, a four-carbon dicarboxylic acid with a trans carbon-carbon double bond. The geometry distinguishes it from its cis isomer.
In the citric acid cycle, oxidation of succinate yields fumarate, and addition of water across the double bond yields malate. This sequence changes the functional groups while preserving the four-carbon framework.[ref]
Succinyl-CoA is coenzyme A carrying a four-carbon succinyl group through a thioester linkage. It is formed during oxidative decarboxylation of 2-Oxoglutarate in the citric acid cycle.
Conversion of succinyl-CoA to succinate can be coupled to formation of a nucleoside triphosphate. This is a direct energy-conserving step in the cycle, distinct from the later use of respiratory electron carriers to produce ATP.[ref]
The citric acid cycle by Hans Adolf Krebs. Discussion of succinyl coenzyme A and energy conservation
Alpha-ketoglutarate is another name for 2-Oxoglutarate, a five-carbon dicarboxylate containing a ketone adjacent to a carboxylate group. The names describe the same carbon skeleton using two positional naming conventions.
Alpha-ketoglutarate links the citric acid cycle with amino acid metabolism: transamination interconverts its carbon skeleton with that of glutamic acid. Its oxidative decarboxylation yields succinyl-CoA and carbon dioxide.[ref]
Isocitrate is a six-carbon tricarboxylate related to citrate by the position of a hydroxyl group. This change makes the hydroxyl-bearing carbon available for oxidation.
In the citric acid cycle, oxidative decarboxylation of isocitrate produces 2-Oxoglutarate, releases carbon dioxide, and reduces a nicotinamide cofactor. Isomerization therefore prepares a carbon skeleton for a reaction that its original arrangement does not readily undergo.[ref]
Oxaloacetate is a four-carbon dicarboxylate with a ketone group adjacent to one carboxylate. It is regenerated in the citric acid cycle rather than consumed as a net reactant on every turn.
Condensation with acetyl-CoA forms citrate; later oxidation of malate regenerates oxaloacetate. Removing oxaloacetate for biosynthesis therefore requires replenishing the cycle's intermediates to sustain flux.[ref]
Acetyl-CoA is coenzyme A carrying an acetyl group through a thioester linkage. It is a central two-carbon donor in metabolism.
Condensation of acetyl-CoA with oxaloacetate forms citrate at the beginning of the citric acid cycle. The same carrier also supplies carbon for biosynthetic pathways, so its fate depends on the cell's metabolic state.[ref]
Coenzyme A is a coenzyme with a terminal thiol group that can carry an acyl group as a thioester. Its nucleotide-containing portion is recognized by enzymes, while the sulfur-linked group participates in chemical transformations.
Acetyl-CoA and succinyl-CoA carry different acyl units on the same coenzyme framework. This reuse of a molecular carrier connects fatty acid metabolism with the citric acid cycle.[ref]
https://www.ebi.ac.uk/chebi/CHEBI:15346. ChEBI: coenzyme A, structure and classification
p-xylene is 1,4-dimethylbenzene, . Its two methyl substituents occupy opposite positions on the benzene ring.
It has the same molecular formula as the ortho and meta isomers but a different molecular symmetry and packing behavior. Comparing these isomers illustrates why a formula is insufficient to predict every physical property of an aromatic compound.
Cyclohexane is the cyclic alkane . Its preferred chair conformation allows near-tetrahedral bond angles and largely staggered neighboring bonds.
Ring flips exchange axial and equatorial positions. Consequently a substituent can retain its up/down orientation while changing the steric interactions that determine conformational preference and reaction accessibility.
Alcohols such as ethanol and glycerol contain hydroxy groups on carbon chemical atoms with only single covalent bonds.
Succinate is the dianion of succinic acid, a four-carbon dicarboxylic acid with structure . It is an intermediate of the citric acid cycle.
Ubiquinone is a membrane-soluble quinone electron carrier with a hydrophobic isoprenoid side chain. Reduction of the quinone headgroup gives ubiquinol.
In the mitochondrial respiratory chain, movement within the membrane transfers reducing equivalents between protein complexes. The hydrophobic chain controls localization, while the headgroup carries out the redox chemistry.
Propidium iodide is a nucleic acid stain used in a flow cytometric DNA-content assay; ribonuclease A removes interfering RNA.[ref]
Cell Cycle Analysis by Propidium Iodide Staining by UCL Institute of Child Health Flow Cytometry Core Facility. Cell Cycle Analysis by Propidium Iodide Staining, p. 2, Procedure steps 6–9
Sodium thiosulfate is the salt , often encountered as a hydrate. Its thiosulfate ion can participate in both oxidation-reduction reactions and metal-ion complex formation.
In photographic fixing, thiosulfate binds silver and helps dissolve residual silver halide. In analytical chemistry, reaction with iodine supports quantitative titration. These applications use different aspects of the same anion's chemistry.
Pinned article: Introduction to the OurBigBook Project
Welcome to the OurBigBook Project! Our goal is to create the perfect publishing platform for STEM subjects, and get university-level students to write the best free STEM tutorials ever.
Everyone is welcome to create an account and play with the site: ourbigbook.com/go/register. We belive that students themselves can write amazing tutorials, but teachers are welcome too. You can write about anything you want, it doesn't have to be STEM or even educational. Silly test content is very welcome and you won't be penalized in any way. Just keep it legal!
Intro to OurBigBook
. Source. We have two killer features:
- topics: topics group articles by different users with the same title, e.g. here is the topic for the "Fundamental Theorem of Calculus" ourbigbook.com/go/topic/fundamental-theorem-of-calculusArticles of different users are sorted by upvote within each article page. This feature is a bit like:
- a Wikipedia where each user can have their own version of each article
- a Q&A website like Stack Overflow, where multiple people can give their views on a given topic, and the best ones are sorted by upvote. Except you don't need to wait for someone to ask first, and any topic goes, no matter how narrow or broad
This feature makes it possible for readers to find better explanations of any topic created by other writers. And it allows writers to create an explanation in a place that readers might actually find it.
Figure 1. Screenshot of the "Derivative" topic page. View it live at: ourbigbook.com/go/topic/derivativeVideo 2. OurBigBook Web topics demo. Source. - local editing: you can store all your personal knowledge base content locally in a plaintext markup format that can be edited locally and published either:This way you can be sure that even if OurBigBook.com were to go down one day (which we have no plans to do as it is quite cheap to host!), your content will still be perfectly readable as a static site.
- to OurBigBook.com to get awesome multi-user features like topics and likes
- as HTML files to a static website, which you can host yourself for free on many external providers like GitHub Pages, and remain in full control
Figure 2. You can publish local OurBigBook lightweight markup files to either OurBigBook.com or as a static website.
Figure 3. Visual Studio Code extension installation.
Figure 5. . You can also edit articles on the Web editor without installing anything locally. Video 3. Edit locally and publish demo. Source. This shows editing OurBigBook Markup and publishing it using the Visual Studio Code extension. 
- Infinitely deep tables of contents:
All our software is open source and hosted at: github.com/ourbigbook/ourbigbook
Further documentation can be found at: docs.ourbigbook.com
Feel free to reach our to us for any help or suggestions: docs.ourbigbook.com/#contact