Chapter 4 – Carbon Chemistry

Section 1: Properties of Carbon Because of its unique ability to combine in many ways with itself and other elements, carbon has a central role in the chemistry of living organisms

Carbon Atoms and Bonding Carbon atoms can form single, double or triple bonds with other carbon atoms. Carbon can form up to 4 bonds This allows carbon atoms to form long chains, almost unlimited in length. Carbon can bond with other carbons, form straight chains, branched chains and rings

The Chemistry of Carbon “organic”: must contain at least one carbon. CH 4 = simplest organic molecule Carbon has 4 valence electrons Therefore, carbon will always make 4 bonds with other atoms Ability to form millions of different compounds with other elements

Forms of Pure Carbon Diamond, graphite, fullerenes and nanotubes are four forms of the element carbon (How diamonds are made) Diamond – crystalline form of carbon in which each carbon atom is bonded strongly to four other carbon atoms Formed from high temps and pressure Melting point is more than 3500 C Can be made artificially and are used in industry as cutting tools

Forms of Pure Carbon Graphite – each carbon atom is bonded tightly to three other carbon atoms in flat layers Bonds are very weak “Lead” in pencils is mostly graphite Used as a lubricant in machines

Forms of Pure Carbon Fullerenes – consists of carbon atoms arranged in the shape of a hollow sphere Called buckyballs after an architect Nanotube – carbon atoms are arranged in the shape of a long hollow cylinder Tiny, light, flexible and extremely strong Good conductors of heat and electricity.

Chapter 4 – Carbon Chemistry Section 2 – Carbon Compounds

Organic Compounds Organic compounds – compounds that contain carbon Many organic compounds have similar properties in terms of melting and boiling points, odor, electrical conductivity and solubility Many are gases at room temperature Many have a strong odor Many do not dissolve in water

Hydrocarbons Hydrocarbon – compound that contains only the elements carbon and hydrogen Hydrocarbons mix poorly with water All hydrocarbons are flammable; CH4 (methane), C 2 H 6 (ethane), C 3 H 8 (propane)

Structure of Hydrocarbons The carbon chains in the hydrocarbon may be straight, branched or ring-shaped Structural formula – shows the kind, number and arrangement of atoms in a molecule Isomer – compounds that have the same chemical formula but different structural formulas which makes them have different properties C 4 H 10

Structure of Hydrocarbons Saturated hydrocarbons – only single bonds, has maximum number a hydrogen atoms attached Unsaturated hydrocarbons – has double or triple bonds, have fewer hydrogen than saturated hydrocarbons

Structure of Hydrocarbons Substituted hydrocarbon – atoms of other elements replace one or more hydrogen atoms in a hydrocarbon Include halogen-containing compounds, alcohols, and organic compounds Alcohol – a substituted hydrocarbon that contains one or more hydroxyl groups hydroxyl group –OH Alcohols dissolve well in water, have higher boiling points than other Hydrocarbons with similar numbers of carbon

Organic acid – a substituted hydrocarbon that contains one or more carboxyl groups Example: citric acid (lemons) acetic acid (vinegar), malic acid (apples), butyric acid (butter) carboxyl group –COOH Ester – compound made by chemically combining an alcohol and an organic acid Have pleasant, fruity smells Responsible for smells of pineapple, bananas, strawberries

Polymers Polymer – large molecule made of a chain of many smaller molecules bonded together Monomer – smaller molecules that make up polymers

There are 4 classes of organic compounds required by all living things called macromolecules. Foods provide these organic compounds which cells of living things use, change, and store These 4 classes are nutrients-substances that provide the energy and raw materials the body needs to grow, repair worn parts, and function properly. Section 3– Life with Carbon

The Four Macromolecules of Life Macromolecule (polymer) made by joining many monomers (single unit) Polymerization: chemical rxn which joins monomers to make polymers The four main classes of biological molecules: 1. Carbohydrates (sugar, starches, cellulose) 2. Lipids (wax, fats, oils, steroids) 3. Proteins (muscle, hair, hormones, enzymes) 4. Nucleic acids (DNA and RNA)

Carbohydrates Carbohydrate – an energy-rich organic compound made of the elements carbon, hydrogen and oxygen Simple carbohydrate – the simplest carbs are sugars (glucose is in your body – C 6 H 12 O 6 ) Complex carbohydrate – a polymer made of smaller molecules that are simple carbs bonded to one another

CARBOHYDRATES: Monomer = Monosaccharide Contain C, H, and O in a 1:2:1 ratio Most end with “ose” An animal’s main energy source Carbs are burned first in the body Monosaccharides: (C 6 H 12 O 6 ): glucose, fructose, galactose Disaccharides: sucrose, lactose, maltose Polysaccharides: (complex carbohydrates) A) glycogen (carb storage animal liver) B) starch (carb storage in plants) C) cellulose (cell walls, cotton) “roughage” D) chitin (exoskeletons of arthropods)

Proteins Proteins – formed from smaller molecules called amino acids Amino acid – a monomer that is a building block of proteins Each amino acid molecule has a carboxyl group (–COOH) and an amino group (–NH 3 ) The body uses proteins from food to build and repair body parts and to regulate cell activities

PROTEINS: Monomer = Amino Acid essential to the structures and activities of life Contain C, H, O, N (S, P) 50% of your dry weight examples of groups of proteins: 1. enzymes (amylase, sucrase, maltase, lactase) 2. structural (collagen, elastin) 3. contractile (actin, myosin) 4. transport (hemoglobin, protein channels) 5. hormones (insulin)

Each amino acid has: An amino group (-NH 2 ) A carboxyl group (COOH) An R group, which distinguishes each of the 20 different amino acids AMINO ACID: Structure * Each amino acid has specific properties based on the R-group * Peptide bonds link amino acids together  polypeptide (protein)

Lipids Lipids – energy-rich compounds made of carbon, oxygen and hydrogen Lipids include fats, oils, waxes and cholesterol Gram for gram, lipids release twice as much energy in your body as do carbohydrates Fatty acids – organic compound that is a monomer of a fat or oil Cholesterol – a waxy lipid in animal cells

LIPIDS: Monomer = Fatty Acids * Mostly C and H atoms linked by nonpolar covalent bonds * reserve energy-storage molecules (burned after carbs are gone) * Insoluble in water (polar) * Soluble in nonpolar solvents (ether) * More energy in lipids than in carbs - 9 cal/g Lipid vs. 4 cal/g Carb * Examples: triglycerides, phospholipids, steroids (cholesterol), waxes, oils, fats * Triglyceride = 3 fatty acids + 1 glycerol * Saturated Fats: all single bonds in chain - solid at room temp (ex: butter, lard) * Unsaturated fats: one or more C=C bond in chain - liquid at room temp (ex: all oils)

Nucleic Acids Nucleic acids – very large organic molecules made up of carbon, oxygen, hydrogen, nitrogen and phosphorus Two types – DNA and RNA Elements that make up all living things… C – Carbon H – Hydrogen N – Nitrogen O – Oxygen P – Phosphorus S – Sulfur

NUCLEIC ACIDS: Monomer = Nucleotide Nucleic acids (DNA and RNA) store and transmit genetic information DNA = Deoxyribonucleic acid RNA = Ribonucleic acid Large macromolecules containing C, H, O, N, P One nucleotide = 5-carbon sugar, phosphate (PO 4- ), nitrogenous base The sugars and phosphates are the backbone for the nucleic acid DNA’s sugar = deoxyribose RNA’s sugar = ribose

Other Compounds in Foods Vitamins-organic compounds that serve as helper molecules in a variety of chemical reactions in your body. Minerals-elements in the form of ions in your body. Water-makes up most of your body’s fluids.