Tiny things within cells that keep them alive - organelles organs tissues biological molecules( organelles, organs, tissues, biological molecules )
Structures that carry out specialized jobs - organs organelles tissues biological molecules( organs, organelles, tissues, biological molecules )
Groups of cells with similar abilities that allow organs to function - tissues organelles organs biological molecules( tissues, organelles, organs, biological molecules )
Chemical compounds that provide physical structure, allow movement, provide energy use - biological molecules organelles organs tissues( biological molecules, organelles, organs, tissues )

An attachment between two atoms that have opposite electrical charges which attract each other - ionic bond covalent bond( ionic bond, covalent bond )
An attachment between two atoms that share one or more pairs of electrons - covalent bond ionic bond( covalent bond, ionic bond )

Store and transfer important information in the cell - nucleic acids carbohydrates lipids proteins( nucleic acids, carbohydrates, lipids, proteins )
Source of energy and structural materials - carbohydrates nucleic acids lipids proteins( carbohydrates, nucleic acids, lipids, proteins )
Store energy, provide insulation, protection - lipids nucleic acids carbohydrates proteins( lipids, nucleic acids, carbohydrates, proteins )
Chains of amino acids that form hair and horns and act as biological catalysts - proteins nucleic acids carbohydrates lipids( proteins, nucleic acids, carbohydrates, lipids )