Unit 1: Biochemistry 

Matter is anything that has mass and occupies space and is composed of atoms. Atoms are composed of smaller particles. The three subatomic particles are Protons, neutrons and electrons. Protons have a positive charge, is located in the nucleus and has a mass of 1.0u. Neutrons are neutral and are also located in the nucleus and also has a mass of 1.0u. Electron has a negative charge, is located outside the nucleus and has a mass of 0.00054u. An element is defined by the number of protons in the nucleus or the atomic number. A number of protons is equal to the number of electrons. isotopes have the same number of protons or atomic number, but different number of neutrons or atomic mass. All isotopes have the same chemical properties just different masses with the exception of radioactivity. Radio isotopes have an unstable nucleus, and emit subatomic particles or energy as they decay into more stable atoms. The three radioactive emissions are alpha particles, beta particles and gamma rays. Alpha particles are the weakest of the three and they have two protons and two neutrons and can we stop by paper. Beta particles are high speed electrons and can’t be stopped my lead. Gamma rays are electromagnetic radiation that can be stopped by a brick of lead. Alpha decay is the loss of neutrons and protons. They keep decaying and losing particles until they become stable. carbon-14 trace movement of carbon through biological pathways like respiration and photosynthesis. Calcium - 45 measures rate of bone formation. Potassium 40 has a half life of 1.3 billion years and is used to date fossils. Iodine - 131 is taken up by thyroid gland and can be imaged to detect abnormalities. Radium - 226 emits radiation that can destroy living cells so it’s used to treat cancer tumors. Radioisotopes are traceable because of the gamma rays they give off. Chemical bonds are formed between atoms by interaction of their respective electrons, an example would be water or glucose. Intermolecular bonds holds 2 or more molecules together. The three types of intermolecular bonds are london force, dipole dipole forces and hydrogen bonds. London forces are very weak and occur between small nonpolar molecules. Methane is an example of london forces. Dipole-Dipole forces occur between polar molecules.