Chapter 6.1 Biochemistry

Atoms Atoms: The building blocks of matter and the smallest particle of an element that exhibits characteristics of that element.  Parts of an atom:  Protons: Positive charged particles found in the nucleus of an atom Atomic number = # of Proton  Neutrons: no charge and are also found in the nucleus of an atom Atomic mass (Mass #) –Atomic Number = # of Neutron  Electrons: Negative charged particles found outside the nucleus of an atom Number of Protons = Number of electrons Have energy levels 1-8 (electron cloud or shells) Valence electrons: the number of electrons found in the outermost shell Quarks: Are the subatomic particles that make up protons, electrons, and neutrons.

Elements, Compounds, and Mixtures Elements : A pure substance that can not be broken down into simpler substances except by nuclear means. *Example: Carbon (C) and Iron (Fe) Compounds : is a pure substance that is composed of atoms of two or more different elements that are chemically combined. *Each of the elements in the compound lose their chemical characteristics when chemically bond. *Example: water H2O Mixture : Combination of two or more components that retain their identities. *Can be broken down by physical means. *Saltwater NaCl + H2O

Elements 92 elements are natural occurring and the others are made in a lab (synthetic) Most two abundant in the universe is Hydrogen 93.5% and Helium 6.3 % Most two abundant on Earth are Oxygen 46.6 % and Silicon 27.7 %

Most elements are identified by a one or two letter abbreviation called symbol (some have three letters).  The first letter is capitalized and the second (or third) are lower cased.  Some symbols are only one letter Only 25 are essential to living organisms.  C, H, N, and O-together make up 96% of the mass in the human body Trace elements are present in living things in very small quantities.  Ex. Cu and Fe

Isotopes and Radiation Isotopes: Form when atoms of the same element have a different mass numbers because they are different amounts of neutrons but the same amount of protons. Ions: charged particles +(cation), or – (anion) Radioactivity: is the spontaneous process through which unstable nuclei emit radiation. During radiation decay both protons and neutrons can be released changing the identity of the element. Alpha, Beta, or Gamma radiation

Types of Mixtures Heterogeneous mixture: Not evenly distributed and often different parts of the mixture have different properties. Ex. Soil Homogeneous mixture: The substances are uniformly distributed, so all parts have the same properties. Ex. Steel, air, brewed coffee, and Kool-Aid

Homogeneous Mixtures are Solutions Made of two parts #1 solute -What is being dissolved #2 solvent -What is doing the dissolving Most are liquid like salt water and magma, but some are solids like bronze (from Tin and Copper) and brass (from Copper and Zinc) and gases like air (mainly Nitrogen and Oxygen) Concentration of a solution is the ratio of the amount of solute to the amount of solvent Solubility-Is the maximum amount of solute that can be dissolved in a solvent.

Types of Bonds Covalent Ionic Hydrogen Metallic

Covalent Bonds Covalent bonds - 2 atoms sharing an electron in the outer most shell.  Examples: sugars, fats, water, and proteins Molecule - A pure substance that consists of atoms held together by covalent bond.  Ex. Water H 2 O  2 H + 1 O Polar covalent bond: Covalent bonds that the atoms do not share the electrons equally. Ex. water  While Nonpolar bonds do share equally Ex. N=N & F-F

Ionic Bonds Ionic bonds - The attractive force between a (+) metal ion and a (-) nonmetal ion. When atoms combine with each other by gaining or losing electrons in outermost energy level  Ex. Na + + Cl - yields NaCl (table salt)

Chemical Reactions Chemical Reactions occur when bonds are formed or broken. Reactants are the elements or compounds in the beginning of a written chemical equation before the reaction takes place: Na + Cl → NaCl ( → means yield sign) Products are the elements or compounds formed after the chemical reaction takes place: Na + Cl → NaCl

All of the chemical reactions that occur within living organisms are known as metabolism.  Metabolic reactions break down and build molecules that are important for the functioning of organisms.

Acids and Bases-pH Scale Acids are compound that produces H+ when dissolved in water  Ex. HCl is added to water and H+ and Cl- forms and the solution of HCl is called Hydrochloric Acid (pH 2) found in the stomach to break down food. Bases are compound that produces an (OH - ) Hydroxide ion when dissolved in water  NaOH is called Sodium Hydroxide Dissolves in water and forms Na+ and OH- ions. (pH 10) pH: pH scale 0-14 with less than 7 is an acid and greater than a 7 is a base and 7 is neutral