Chemistry of Life

"Organic chemistry is the study of carbon compounds. Biochemistry is the study of carbon compounds that crawl." ~Mike Adams Chemistry of Life Biochemistry is the study of the chemical substances and vital processes occurring in living organisms.

Unit Concepts • Atomic Theory • Chemical Reactions: Bonding • Properties of Water • Macromolecules • Enzymatic reactions

Biochemistryis the study of biologically important interactions between compounds. • Biology is, at its simplest form, the study of chemistry. • Even large-scale events in biology are controlled by some molecular scale chemical action.

Everything in the universe is composed of matter. • Matter consists of atoms. • Atoms are the smallest unit that cannot be broken down by chemical means. • A group of like atoms is called an element (purist form).

Atomic structure is shown as a Bohr model. • The number of protons is written as the atomic number on the Periodic table. • The number of neutrons is usually equal to the number of protons. • The number of neutrons is determined by subtracting the atomic number from the atomic mass. • An atom is an isotope when it has a different number of neutrons than the periodic table predicts. • The nucleus is composed of protons and neutrons. • Electrons surround the nucleus.

Organization of electrons • Electrons exist in energy levels. • The first level (up to 2 electrons ) must be filled before electrons are placed into the next. • The second level (up to 8 electrons) needs to be filled before electrons are placed into the 3rd (up to 8 electrons) 2, 8, 8

Compoundsare groups of 2 or more different type of atoms that are joined together. • Atoms can be joined together using three different types of bonds. • Covalent Bonds • Ionic Bonds • Hydrogen Bonds

Covalent Bonds Covalent bonds occur when two or more atoms share electrons.

Hydrogen bonds occur in water when oxygen shares the electrons unequally. • This causes the water to be more negative on the oxygen side and more positive on the hydrogen sides. • The presence of charges within a molecule causes it to be a polar molecule which will attract other polar molecules and charged particles called ions.

Ions are atoms that have a strange number of electrons (+ or -) and attractions to one another, as well as polar molecules. • Electrons are gained or lost to achieve stability. • Sodium (Na) has one electron in its outer shell while Chlorine (Cl) has 7. Sodium loses its extra and Chlorine picks it up. • Sodium is now positive and is attracted to the negative Chlorine. This is called an Ionic Bond.

The strengths of the 3 different types of bonds give the molecules that use them different properties. • Covalent bonds are very strong and require much energy to break them (strongest). • Ionic bonds are easily broken by the presence of other local charges • Hydrogen bonds are broken when heat causes the molecules to become more active and break apart. (weakest).

Unit 4: Concepts • Atomic structure and bonding (I) • Properties of water (I) • Macromolecules (E) • Enzymatic reactions (E)

Why are 2/3 of the molecules in the human body comprised of H2O? • Water stores heat very efficiently. • The evaporation of water enables organisms to release heat and maintain homeostasis.

The hydrogen bonding of water causes ice to freeze in a crystal lattice (extending the distance between molecules). This causes ice to expand, become less dense and float on top of the more dense water once it freezes.

An additional property of water that makes it biologically important is its ability to bond to itself and other substances. Surface Tension • Cohesionis the attraction between water molecules due to hydrogen bonding (surface tension of water- drops and films). • Adhesion is the attraction of water to other polar substances. • Cohesion and adhesion allow water to crawl up the roots and stems of a plant.

Transpiration and the flow of water through a plant.

A solution is a mixture where one or more substances (solutes) are evenly distributed in another substance (solvent). • Ionic and polar compounds dissolve well in water. • Ions are attracted to the charges on H2O. • Atoms become evenly distributed in the water if their concentration is low enough. • Polar molecules stick together and shove non-polar substances, like oil, together. • Biochemical reactions occur best within a liquid environment which allows molecules to interact with one another.

Water frequently separates into ions: Hydrogen ions (H+) and Hydroxide ions (OH-). • This reaction works in both directions. • In pure water, the concentration of H+ and OH- are always the same.

The pH scale is a measure of the concentrations of H+ and OH-. • Acids have a higher concentration of H+ than pure water. • Bases have a higher concentration of OH- than pure water.

Macromoleculesare large molecules built around a frame of carbon and are referred to as being organic. These carbon-containing molecules have specific properties which make them biologically important . • Macromolecules are covalently bonded giving them strength. • The four major macromolecules constitute the primary biological building blocks. • Macromolecules are composed of the 6 most biologically important atoms: Sulfur, Phosphorus, Oxygen, Nitrogen, Carbon and Hydrogen “SPONCH”

Carbohydrates are a key source of cellular energy. • Ratio = 1:2:1 1 Carbon: 2 Hydrogen: 1 Oxygen (There may be many of each) Example… glucose -> C6H12O6 • A monosaccharide(single sugar) called glucose is produced by photosynthesis. • A disaccharides(double sugar) called sucrose is table sugar. • Polysaccharides(3 or more sugars) are formed for “longer-term” energy storage (starches) or structural purposes (cellulose in plants).

Lipidsare non-polar molecules used for long-term energy storage and as a key component in cell membranes. • Bonds hold energy, so fat molecules which contain many bonds, store lots of energy. • Saturated fats are chains where each carbon is bonded to 2 hydrogen (a lot more hydrogen than a carbohydrate). • Unsaturated fats are chains where some carbons are only bonded to one hydrogen.

Nucleic Acids like DNA and RNA hold and carry an organism's plans for life. • Nucleic acids are composed of chains of nucleotides. • DNAis a double strand of nucleotides, responsible for storing information in the cells nucleus. • RNAis a single strand of nucleotides used to transport information out of the nucleus during the manufacture of proteins.

Proteins are chains of amino acids. • DNA provides instructions on how to assemble the amino acids into specific proteins. • Since some amino acids are polar and others aren't, proteins twist into specific shapes dependent on their sequences. • The shape of a protein determines its functionality and interaction with other molecules. • Proteins have many functions in your body: • Enzymes, support structures, antibodies

Energy is defined as the ability to move or change matter. • Energy comes in 7 forms. • Organisms need to break down chemical energy for their life processes. • Energy can be stored or released by chemical reactions. • Chemical reactions are constantly happening in an organism. • Reactants are chemically altered to produce products.

Chemical reactions absorb or release energy. • Decomposition reactions release energy. • Bond energy is released when large molecules are broken down. • The energy is used, “re-stored” in ATP or released as heat and light.

Chemical reactions absorb or release energy. • Synthesis reactions require energy. • Bond energy must be put in to combine small molecules and make bigger ones. • ATP may be used in heterotrophs. • Sunlight or ATP may be used by autotrophs.

Activation energy is needed to start a chemical reaction. • Even a decomposition reaction needs energy to get it going. Example: A boulder rolling down a hill and releasing energy as it goes, still needed a push to get started.

Enzymes help biochemical reactions occur at usable levels. • Enzymes allow reactions to occur more quickly. • Enzymes allow reactions to occur at lower temperatures. • Enzymes lower the activation energy required to start a reaction. • Most reactions would still occur without their enzymes, but at rates unsuitable to maintain homeostasis.

Chemistry of Life