: genetic alteration of a gene or its expression that is inferred to take place from the observation that certain genes are expressed differently depending on whether they are inherited from the paternal or maternal parentâcalled also genetic imprinting, imprinting. genetic alteration of a gene or its expression that is inferred to take place from the observation that certain genes are expressed differently depending on whether they are inherited from the paternal or maternal parentâcalled also genetic imprinting, imprinting.
Atoms vs. Ions. Atoms are neutral; they contain the same number of protons as electrons. By definition, an ion is an electrically charged particle produced by either removing electrons from a neutral atom to give a positive ion or adding electrons to a neutral atom to give a negative ion. When an ion is formed, the number of protons does not change. Neutral atoms can be turned into positively charged ions by removing one or more electrons. A neutral sodium atom, for example, contains 11 protons and 11 electrons. By removing an electron from this atom we get a positively charged Na + ion that has a net charge of +1. Atoms that gain extra electrons become negatively charged.
Definition of electron. : an elementary particle consisting of a charge of negative electricity equal to about 1.602 Ã 10â19 coulomb and having a mass when at rest of about 9.109 Ã 10â31 kilogram or about 1â1836 that of a proton.