There is no limit to the number of carbon atoms that can be linked together, the only limitation being that the molecule is acyclic, is saturated, and is a hydrocarbon.

Alkanes can be viewed as a molecular tree upon which can be hung the more biologically active / reactive portions ( functional groups ) of the molecule.

Likewise, a group of atoms can remain bound to each other, forming a molecule.

The term originally came from antibody generator and was a molecule that binds specifically to an antibody, but the term now also refers to any molecule or molecular fragment that can be bound by a major histocompatibility complex ( MHC ) and presented to a T-cell receptor.

Depending on the antigen presented and the type of the histocompatibility molecule, several types of immune cells can become activated.

Different antibody idiotypes, each having distinctly formed complementarity determining regions, correspond to the various " locks " that can match " the keys " ( epitopes ) presented on the antigen molecule.

The advantage of this technique is that total and background absorption are measured with the same emission profile of the same lamp, so that any kind of background, including background with fine structure can be corrected accurately, unless the molecule responsible for the background is also affected by the magnetic field ; the disadvantage is the increased complexity of the spectrometer.

The molecule can thus be thought of as a two-bladed propeller.

Two monosaccharides can be joined together using dehydration synthesis, in which a hydrogen atom is removed from the end of one molecule and a hydroxyl group (— OH ) is removed from the other ; the remaining residues are then attached at the sites from which the atoms were removed.

The reverse reaction can also occur, using a molecule of water to split up a disaccharide and break the glycosidic bond ; this is termed hydrolysis.

Bonding can be described with three bonding electron pairs and two antibonding electrons, whose spins are aligned, such that the molecule has nonzero total angular momentum.

In organic chemistry a carbonate can also refer to a functional group within a larger molecule that contains a carbon atom bound to three oxygen atoms, one of which is double bonded.

That system can be a single molecule, a group of molecules, or a solid.

The purpose of the CIP system is to assign an R or S descriptor to each stereocenter and an E or Z descriptor to each double bond so that the configuration of the entire molecule can be specified uniquely by including the descriptors in its systematic name.

The DNA molecule may be circular or linear, and can be composed of 100, 000 to over 3, 750, 000, 000 nucleotides in a long chain.

By chemotactic selection we can determine whether a still uncharacterized molecule acts via the long-or the short-term receptor pathway.

The energies involved in the various motions of the molecule can then be broken down into three categories.

For microscopic, atomic-level systems like a molecule, angular momentum can only have specific discrete values given by

Another way a diatomic molecule can move is to have each atom oscillate — or vibrate — along a line ( the bond ) connecting the two atoms.

The energy of formation of a molecule containing only single bonds then can be approximated from an electronegativity table, and depends on the constituents and sum of squares of differences of electronegativities of all pairs of bonded atoms.

Such a formula for estimating energy typically has relative error of order of 10 %, but can be used to get a rough qualitative idea and understanding of a molecule.

The effective nuclear charge, Z * experienced by valence electrons can be estimated using Slater's rules, while the surface area of an atom in a molecule can be taken to be proportional to the square of the covalent radius, r < sub > cov </ sub >.

It is not a coincidence that this happens in the " visible range ," as the mechanism of vision involves the change in bonding of a single molecule ( retinal ) which absorbs light in the rhodopsin the retina of the human eye.

Animals which detect infrared do not use such single molecule processes, but are forced to make use of small packets of water which change temperature, in an essentially thermal process that involves many photons ( see infrared sensing in snakes ).

It was classically argued that the binding of an oxygen molecule placed high-spin iron ( II ) in an octahedral field of strong-field ligands ; this change in field would increase the crystal field splitting energy, causing iron's electrons to pair into the low-spin configuration, which would be diamagnetic in Fe ( II ).

At the lower end of the visible light spectrum, EMR becomes invisible to humansinfrared because its photons no longer have enough individual energy to cause a lasting molecular change ( a change in conformation ) in the visual molecule retinal in the human retina.

If inversion through the center of symmetry in a molecule results in a phase change for the molecular orbital, then the MO is said to have ungerade, u, symmetry.

The various conditions can use one or more physical mechanisms to lower the solubility of the molecule ; for example, some may change the pH, some contain salts of the Hofmeister series or chemicals that lower the dielectric constant of the solution, and still others contain large polymers such as polyethylene glycol that drive the molecule out of solution by entropic effects.

Molecules will absorb infrared light if the frequency of the bond vibration is resonant with ( identical to ) the incident light frequency, where the molecular vibration at hand produces a change in the dipole moment of the molecule.

The difference in energy between that which is necessary to release an ion from its lattice and the energy given off when it combines with a solvent molecule is called the enthalpy change of solution.

The process of vision relies on the light-induced isomerisation of the chromophore from 11-cis to all-trans resulting in a change of the conformation and activation of the photoreceptor molecule.

That is, the numerical charge of an atom or molecule must change sequentially, always moving from one number to an adjacent, or sequential, number.

A change in the molecular polarization potential — or amount of deformation of the electron cloud — with respect to the vibrational coordinate is required for a molecule to exhibit a Raman effect.

Under normal circumstances, it acts by causing a conformational change in a receptor molecule, which results in a change in the binding affinity of the ligand.

Surface pressure can also refer to the change of surface tension as a function of the area of water surface available to each molecule in a solution.

As well as the electronic transitions discussed above, the energy of a molecule can also change via rotational, vibrational, and vibronic ( combined vibrational and electronic ) transitions.

Absorption lines are typically classified by the nature of the quantum mechanical change induced in the molecule or atom.

Electronic lines correspond to a change in the electronic state of an atom or molecule and are typically found in the visible and ultraviolet region.

Phosphorylation is a chemical reaction in which a small phosphate group is added to another molecule to change that molecule's activity.

Although the bond dissociation energy D for a carbon-carbon single bond is relatively high ( about 375 kJ / mol ) and cracking is highly endothermic, the large positive entropy change resulting from the fragmentation of one large molecule into several smaller pieces, together with the extremely high temperature, makes T ∆ S ° term larger than the ∆ H ° term, thereby favoring the cracking reaction.

Conformational changeIt is the retinal molecule that changes its conformation when absorbing a photon, resulting in a conformational change of the surrounding protein and the proton pumping action.

The effect of this release is a conformational change in the molecule that pulls against the actin.

This base pair will change from an A-T to a G-C or from a G-C to an A-T after a number of replication cycles, depending on whether 5-BrU is within the DNA molecule or is an incoming base when it is enolized or ionized.