AP Biology Biochemistry

Atomic Structures Atoms are basic units of matter Protons (+1) , Neutrons (0), Electrons (-1) Depending on their energy levels, they are in different states. Ground state: At lowest possible potential energy. Excited state: At any state where the system is at higher than the minimum. Isotopes: atoms of one element that vary in neutrons. Are all chemically identical Radioisotopes: decay at a rate known as half-life, often used in medicine. Tracers: used to TRACE certain chemicals in natural pathways Ex: Iodine (radioactive) to give information about thyroid gland metabolism. Bonding In biology, the two main types are Ionic and Covalent Ionic Bonds Transfer of electrons Receiver is called anion (a negative ion) Donor is called the cation Covalent Bonds