Definition

Noun: - A univalent alkyl radical: The methyl group is a fundamental chemical unit with the formula CH₃⁻. It consists of one carbon atom bonded to three hydrogen atoms and has one free valence, allowing it to attach to other atoms or molecules. It is derived from methane (CH₄) by the removal of one hydrogen atom.

Usage and Examples

• As a constituent part of larger molecules:
  • In organic chemistry, a methyl group is often added to or removed from compounds in reactions called methylation and demethylation.
  • The addition of a methyl group to the DNA molecule can affect gene expression.
• Describing molecular structure:
  • The compound toluene contains a methyl group attached to a benzene ring.
  • The difference between ethanol and methanol is that methanol has only a methyl group bonded to a hydroxyl group.

Advanced Usage

• In biochemistry and genetics: Methyl groups play a critical role in epigenetic regulation, where they modify DNA and histones.
  • Hypermethylation of a gene promoter, involving many methyl groups, can silence that gene.
• As a reference in spectroscopy: The presence of methyl groups in a molecule gives characteristic signals in techniques like NMR (Nuclear Magnetic Resonance).
  • The NMR spectrum showed a distinct peak for the protons in the methyl group.

Variants and Related Words

• Methylate (verb): To introduce a methyl group into a compound.
  • Scientists methylate the compound to study its new properties.
• Methylation (noun): The chemical process of adding a methyl group to a substrate.
  • DNA methylation is a common epigenetic modification.
• Methylated (adjective): Describing a compound that has had a methyl group added.
  • Methylated spirits are ethanol denatured by the addition of methanol.

Synonyms

• Methyl radical: A less common but technically accurate synonym.
• CH₃ group: A formulaic synonym used in chemical notation.

Related Phrases and Concepts

• Methyl donor: A molecule, such as S-adenosyl methionine (SAM), that can transfer a methyl group to another molecule.
  • SAM serves as the primary methyl donor in biological systems.
• Methyl terminus: Refers to the end of a hydrocarbon chain that is a methyl group.
  • The fatty acid has a methyl terminus at one end and a carboxyl group at the other.

Noun

1. the univalent radical CH3- derived from methane