Class II MHC glycoproteins expressed predominantly on pAPCs, where they primarily present exogenous antigenic peptides to CD4+ T cells.

#Id: 7753

#Unit 1. Molecules and their Interaction Relevant to Biology

Electron affinity: The enthalpy change that results from adding an electron to a gaseous atom.

Electron affinity is becoming less negative (less exothermic) and less likely to gain an electron. 

#Id: 7754

#Unit 1. Molecules and their Interaction Relevant to Biology

#Id: 7755

#Unit 1. Molecules and their Interaction Relevant to Biology

Electronegativity is a measure of the tendency of an atom to attract a bonding pair of electrons. The Pauling scale is the most commonly used.

#Id: 7756

#Unit 1. Molecules and their Interaction Relevant to Biology

Fluorine (the most electronegative element) is assigned a value of 4.0, and values range down to cesium and francium which are the least electronegative at 0.7

#Id: 7757

#Unit 1. Molecules and their Interaction Relevant to Biology

Molecules are groups of atoms that behave as a single unit.

#Id: 7758

#Unit 1. Molecules and their Interaction Relevant to Biology

A molecule is the smallest part of a substance that has the physical and chemical properties of that substance. In some respects, a molecule is similar to an atom. A molecule, however, is composed of more than one atom.