Chapter 6.1

Biochemistry

AtomsAtoms: 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 atomAtomic number = # of Proton

Neutrons: no charge and are also found in the nucleus of an atomAtomic mass (Mass #) –Atomic Number = # of Neutron

Electrons: Negative charged particles found outside the nucleus of an atom Number of Protons = Number of electronsHave energy levels 1-8 (electron cloud or shells)Valence electrons: the number of electrons found in

the outermost shellQuarks: 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 H2OMixture: Combination of two or more

components that retain their identities. *Can be broken down by physical means.*Saltwater NaCl + H2O

Elements92 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 bodyTrace elements are present in living

things in very small quantities.Ex. Cu and Fe

Isotopes and RadiationIsotopes: 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 MixturesHeterogeneous 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

CovalentIonicHydrogenMetallic

Covalent BondsCovalent 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 H2O 2 H + 1 O

Polar covalent bond: Covalent bonds that the atoms do not share the electrons equally. Ex. waterWhile Nonpolar bonds do share equally Ex.

N=N & F-F

Ionic BondsIonic BondsIonic 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 levelEx. Na+ + Cl- yields NaCl (table salt)

Chemical ReactionsChemical ReactionsChemical 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 waterEx. 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 waterNaOH 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