Small molecules, such as drugs, go unnoticed.
Those proteins are much-needed molecules such as hormones, digestive enzymes and neurotransmitters.
Other similar-sized molecules – such as ammonia (NH3) and hydrogen chloride (HCl) – are also gases.
Watson believes that rather than being wholly bad, oxidising molecules, such as hydrogen peroxide, are crucial for the body's health.
The pore size of the wood is such that small molecules such as water move through the wood more easily than larger molecules such as alcohol.
Diatomic molecules (such as oxygen) and polyatomic molecules (such as water) have additional rotational motions that also store thermal energy in their kinetic energy of rotation.
Hydrogen is usually tied up in more complex molecules, such as hydrocarbons.
Complicated molecules such as enzymes and drugs can be modelled fairly easily.
Water-soluble molecules, such as the polypeptide hormone insulin, bind to receptors at cell surfaces.
The walled cells of plants and fungi are held together by other molecules, such as pectin.
Atoms may combine further into molecules such as the water molecule, H2O.
