Molecules of Life

• Covalent Bond: Type of chemical bonf which two atoms share a pair of electrons, to create a full outer shell.
• Ionic Bond: A bond between a positive ion which has lost an electron(s) and a negative ion which has gained an electron(s).
• Hydrogen Bond: Chemical bond between the positive charge on a hydrogen atom and the negative charge of another atom of an adjacent molecule.
• Polar Molecule: A molecule which has a partially positive charge in one part of the molecule and a completely negative charge in another part (a dipole).
• Monomer: One of many small molecules that combine together to form a polymer.
• Polymer: Large molecule made up of many repeating smaller molecules (monomers).
• The process by which polymers are formed is called polymerisation.
• Carbohydrates, proteins and nucleic acids are examples of polymers.
• Monosaccharides, amino acids and nucleotides are examples of monomers.
• Condensation Reations: Chemical process in which two molecules combine to form a more complex one with the elimination of a simple substance, usually water.
• Many biological polymers are formed by condenarion reactions.
• Hydrolysis: The breaking down of large molecules into smaller ones by the addition of water molecules.
• Metabolism: All the chemical processes that take place in living organisms.
• Mole: The mass of a substance containing the same number of fundamental units as there are atoms in exactly 12g of C12.
• Molar (M) Solution: An aqueous solution that contains 1 mole of solute in 1 litre of solution.
• Atoms: Atoms are the smallest units of chemical element to exist independently.
• Neutrons: Occur in the nucleus of an atom and have the same mass as protons, but no electrical charge.
• Protons: Occur in the nucleus of an atom and have the same mass as neutrons, but have a positive charge.
• Electrons: Orbit in shells around the nucleus. They have an extremely small mass and they are negatively charged. Also, their number determines the chemical properties of an atom.
• An atom has no overall charge.
• The atomic number is the number of protons in an atom (the smaller number).
• The mass number is the total number of protons and neutrons in an atom (bigger number).
• Isotopes: Have the same number of protons, but a different number of neutrons. They have the same chemical properties but are different in mass.
• The loss of an electron leads to the formation of a positive ion.
• The gaining of an electron leads to the formation of a negative ion.