| A | B |
|---|
| atom | smallest unit of matter |
| proton | positive part of the atom |
| neutron | neutral part of the atom- no charge |
| electron | negative part of the atom |
| element | pure substance made of only one kind of atom |
| DNA | stores hereditary information |
| ion | an atom or molecule that has gained or lost one or more elctrons |
| ionic bonds | form when molecules have opposite charges |
| covalent bonds | bond formed when 2 atoms share electrons |
| compound | substance made of two or more different elements |
| molecule | group of atoms held together by covalent bonds |
| hydrogen bond | weak chemical attraction between polar molecules |
| polar molecule | has both negative and positive poles |
| nonpolar molecule | have no negative or positive poles |
| organic compounds | all contain carbon |
| carbohydrates | include sugars |
| polysaccharides | are carbohydrates |
| sugars | organic molecules classified as carbohydrates |
| acids | have pH less than 7 |
| bases | have pH greater than 7 |
| lipids | nonpolar molecules not soluble or mostly insoluble in water |
| lipids include | saturated fats and ear wax |
| lipids | ARE soluble in oil |
| enzymes | increase speed of chemical reactions |
| enzymes | lower activation energy of a reaction |
| ATP | stores energy for cells to use in bonds between its phosphates |
| Sodium Chloride | is an example of an ionic compound |
| reactants | starting materials for chemical reactions |
| products | new substances formed during chemical reactions |
| Water helps cells maintain homeostasis | because it has the ability to hold in heat |
