Biochemistry The Chemistry of Life

Is chemistry really that important to learn about? Of course it is!!! Chemicals make up EVERYTHING in our bodies, as well as everything we eat! Chemicals are EvERYwHErE!!! 4 important types of organic molecules are: Carbohydrates, Lipids, Proteins and Nucleic Acids

But first….a little review Elements: simplest form of a substance - cannot be broken down any further without changing what it is Atom: the actual basic unit - composed of protons, neutrons, and electrons

Atomic structure Just like cells are the basic unit of life, the ATOM is the basic unit of matter. They are very small. If placed side by side one million would stretch a distance of 1cm. The atom is made up of 3 particles. Particle Charge PROTON + NEUTRON NEUTRAL ELECTRON -

Isotopes atoms of the same element that HAVE A DIFFERENT NUMBER OF NEUTRONS Some isotopes are radioactive. This means that their nuclei is unstable and will break down at a CONSTANT RATE over time. There are several practical uses for radioactive isotopes: CARBON DATING TRACERS KILL BACTERIA / CANCER CELLS

Ionic Bonds Occur when 1 or more electrons are TRANSFERRED from one atom to another. When an atom loses an electron it is a POSITIVE charge. When an atom gains an electron it is a NEGATIVE charge These newly charged atoms are now called IONS Example: NaCl (SALT)

Covalent bonds Occur when electrons are SHARED by atoms. These new structures that result from covalent bonds are called MOLECULES ** In general, the more chemical bonds a molecule has the more energy it contains

Water—The Mysterious Molecule Because water (H20) is a polar molecule, it has many unique properties. Slightly +Hydrogens are attracted to slightly –Oxygens These attractions are called hydrogen bonds and are the reason water: is the only substance that is less dense as a solid Has a high specific heat/heat capacity Is attracted to itself (cohesion) and other substances (adhesion)

pH scale In water, some H20 breaks apart into H+ and OH- If the amount of each ion is equal, the solution has a pH of 7 The more H+, the more acidic the solution 0 – 6 acid 6-7 neutral 8-14 base

Carbon chemistry 4 valence electrons, Can form 4 bonds Readily bonds with other carbons Can form long carbon chains, or carbon rings Can form single, double or even triple bonds

Molecules of Life Carbohydrates (CHO) Sugars and starches Lipids (CHO) Polymer: Large molecule made up of repeating subunits Monomer: smaller molecules that make up polymers Carbohydrates (CHO) Sugars and starches Lipids (CHO) Fats, oils, waxes and steroids Proteins (CHONS) Amino acids and enzymes Nucleic Acids (CHONP) DNA and RNA

Carbohydrates Monosaccharides (1C:2H:1O) Glucose (made by plants during photosynthesis) Fructose Galactose

Carbohydrates, cont’ Disaccharides Polysaccharides Two monosaccharides Sucrose (fructose + glucose) Lactose (glucose + galactose) Polysaccharides 3 or more monosaccharades Starch (plant energy storage) Glycogen (animal energy storage) Cellulose (plant structure)

Lipids More C, less H and O Insoluble in water Used for long term energy storage and insulation Fatty Acids, Triglycerides, Waxes and Steroids

Lipids, cont’ Fatty Acids Make up most lipids Long hydrocarbon chain with a carboxyl group (COOH) on one end Carboxyl group is polar (hydrophilic) Hydrocarbon chain is nonpolar (hydrophobic) In a cell membrane, fatty acids are arranged in a double layer, with chains pointing towards eachother

Saturated fats vs Unsaturated fats Hydrocarbon chain is ‘saturated’ with hydrogens (all single bonds) Solid at room temperature Usually animal based                                                              

Unsaturated Fats Contain one or more double bonds Liquid at room temperature Usually plant based                                                                        

Proteins Contain H, O, C and Nitrogen Main component of our body tissue Made up of chains of amino acids Amino acids = monomers Polypeptide/protein = polymer

Proteins, cont’ Amino acids Monomers that form proteins Basic structure: C with a carboxyl (COOH), amino (NH2), H and ‘R’ groups attached

Proteins, cont’ Enzymes Specific proteins that speed up chemical reactions Not affected by the reaction “Induced fit” model (used to be called ‘lock and key’)

Nucleic Acids Complex polymers made of monomers called nucleotides Store important information in the cell Deoxyribonucleic acid (DNA) Stores most of the information necessary for cell function Ribonucleic acid (RNA) Stores and transfers information for making proteins

Vocabulary check… Macromolecule Polymer Carbohydrate Lipid Protein Amino acid Nucleic acid Nucleotide

FUNCTIONAL GROUPS Functional groups are structural building blocks that determine the characteristics of a compound. One functional group important to living things is the hydroxyl, represented by --OH. (Table 3-1) An alcohol is an organic compound with a Hydroxyl Group attached to one of its Carbon Atoms. The hydroxyl group makes alcohol a polar molecule, which means it is soluble in water Other functional groups important to living things are shown in Table 3-1.

A little more about enzymes… Most of the reactions that take place in our body require enzymes.

OUCH!!!!!!!

**EXTRA CREDIT OPPORTUNITY** Speaking of fatty acids… Find out: What trans-fatty acids are (trans fats) How they are formed Why they are not good for us What kind of foods have them Turn in by Friday for 5 EC points

How are they formed? Dehydration Synthesis Sometimes called a condensation reaction 2 monomers + energy + enzymes  polymer + H2O

How are they broken down? Hydrolysis reaction Reverse of a dehydration synthesis reaction Hydro = water Lysis = breaking apart Requires enzymes Releases energy (heat)

Lipids, cont’ Triglycerides Three fatty acid chains joined to one molecule of glycerol Either oil or fat depending on state at room temperature

Lipids, Cont’ Waxes Long fatty acid chain joined to a long alcohol chain Highly waterproof Protective barrier in plants and animals (earwax)

Lipids, cont’ Steroids Unlike other lipids, composed of 4 carbon rings Considered lipids because they are insoluble in water Ex. Hormones, nerve tissues, venoms, plant poisons