Lesson Overview Carbon Compounds Lesson Overview 2.3 Carbon Compounds Lesson Overview Carbon Compounds THINK ABOUT IT In the early 1800s, many chemists called the compounds created by organisms “organic,” believing they were fundamentally different from compounds in nonliving things. We now understand that the principles governing the chemistry of living and nonliving things are the same, but the term “organic chemistry” is still around. Today, organic chemistry means the study of compounds that contain bonds between carbon atoms, while inorganic chemistry is the study of all other compounds. Lesson Overview Carbon Compounds The Chemistry of Carbon Carbon atoms have four valence electrons, allowing them to form strong covalent bonds with many other elements (including hydrogen, oxygen, phosphorus, sulfur, and nitrogen). Carbon atoms can also bond to each other (this gives carbon the ability to form millions of different large and complex structures). Living organisms are made up of molecules that consist of carbon and these other elements. Lesson Overview Carbon Compounds The Chemistry of Carbon Carbon-carbon bonds can be single , double , or triple covalent bonds. METHANE BUTADIENE ACETYLENE Lesson Overview Carbon Compounds The Chemistry of Carbon Chains of carbon atoms can be straight , branched , or even close up on themselves to form rings . BUTANE ISOOCTANE BENZENE Lesson Overview Carbon Compounds Macromolecules Many of the organic compounds in living cells are macromolecules. Macromolecule means “giant molecule” Macromolecules are made from thousands or even hundreds of thousands of smaller molecules. Lesson Overview Carbon Compounds Macromolecules Most macromolecules are formed by a process known as polymerization , in which large compounds are built by joining smaller ones together. The smaller units, or monomers , join together to form polymers . The monomers in a polymer may be identical or different. Lesson Overview Carbon Compounds Macromolecules Biochemists sort the macromolecules found in living things into groups based on their chemical composition. The four major groups of macromolecules found in living things are carbohydrates, lipids, nucleic acids, and proteins. Lesson Overview Carbon Compounds Carbohydrates – Elements Carbon Hydrogen Oxygen The ratio is usually 1 : 2 : 1 (C:H:O) Lesson Overview Carbon Compounds Carbohydrates – Monomer Monosaccharides (single sugar / simple sugar) Glucose Galactose (a component of milk) Fructose (found in many fruits) Lesson Overview Carbon Compounds Carbohydrates – Uses Living things use carbohydrates as their main source of energy. The breakdown of sugars, such as glucose, supplies immediate energy for cell activities. Plants, some animals, and other organisms also use carbohydrates for structural purposes. Lesson Overview Carbon Compounds Carbohydrates – Examples Disaccharide (two single sugar molecules) Sucrose (table sugar) – Glucose and fructose joined together Lesson Overview Carbon Compounds Carbohydrates – Examples Polysaccharides (many single sugar molecules) Glycogen (excess sugar storage in animals) o When the level of glucose in your blood runs low, glycogen is broken down into glucose, which is then released into the blood Starch (excess sugar storage in plants) Cellulose (polysaccharide found in plant cell walls that give the cells strength and rigidity) Lesson Overview Carbon Compounds Lipids – Elements Carbon Hydrogen Oxygen Lipids have a large number of C-H bonds and less oxygen than carbohydrates (Ex. C 57 H110 O6) Lesson Overview Carbon Compounds Lipids – Structure Unlike carbohydrates, lipids do not have a monomer . Lipids are formed when a glycerol molecule (backbone) combines with compounds called fatty acids. Lesson Overview Carbon Compounds Lipids – Structure If each carbon atom in a lipid’s fatty acid chains is joined to another carbon atom by a single bond, the lipid is said to be saturated. If there is at least one carbon -carbon double bond in a fatty acid, the fatty acid is said to be unsaturated. Lipids whose fatty acids contain more than one double bond are said to be polyunsaturated. Lesson Overview Carbon Compounds Lipids – Uses and Examples Lipids can be used to story energy, as insulation, or as a protective coating (cell membrane) Steroids synthesized by the body are lipids as well. Many steroids, such as hormones, serve as chemical messengers Examples of lipids include fats, oils, and waxes Lipids are nonpolar molecules; therefore, they are water insoluble Lesson Overview Carbon Compounds Nucleic Acids – Elements Carbon Hydrogen Oxygen Nitrogen Phosphorus Lesson Overview Carbon Compounds Nucleic Acids – Monomer Nucleotides Nucleic acids are polymers assembled from individual monomers known as nucleotides Nucleotides consist of a 5-carbon sugar, a phosphate group (–PO 4), and a nitrogenous base. Individual nucleotides can be joined by covalent bonds to form a polynucleotide, or nucleic acid. Lesson Overview Carbon Compounds Nucleic Acids – Uses and Examples Nucleic acids store and transmit hereditary, or genetic, information. Examples include ribonucleic acid (RNA) and deoxyribonucleic acid (DNA). RNA contains the sugar ribose and DNA contains the sugar deoxyribose. Lesson Overview Carbon Compounds Protein – Elements Carbon Hydrogen Oxygen Nitrogen Lesson Overview Carbon Compounds Protein – Monomer Amino acids Amino acids are compounds with an amino group (–NH 2) on one end and a carboxyl group (–COOH) on the other end. Lesson Overview Carbon Compounds Protein – Monomer All amino acids are identical in the amino and carboxyl groups. Any amino acid can be joined to any other amino acid by a peptide bond formed between these amino and carboxyl groups. Amino acids differ from each other in a side chain called the R-group (or variable group), which have a range of different properties. Some R-groups are acidic and some are basic Some R-groups are polar and some are nonpolar Lesson Overview Carbon Compounds Protein – Monomer Covalent bonds called peptide bonds link amino acids together to form a polypeptide. A protein is a functional molecule built from one or more polypeptides. Lesson Overview Carbon Compounds Protein – Uses and Examples Proteins perform many varied functions, such as controlling the rate of reactions and regulating cell processes (enzymes), forming cellular structures, transporting substances into or out of cells, and helping to fight disease. Examples include enzymes, hemoglobin (transports oxygen), and actin / myosin (in muscle cells) Lesson Overview Carbon Compounds Proteins – Levels of Organization Proteins have four levels of structure. A protein’s primary structure is the sequence of its amino acids. Secondary structure is the folding or coiling of the polypeptide chain. Lesson Overview Carbon Compounds Proteins – Levels of Organization Tertiary structure is the complete, three-dimensional arrangement of a polypeptide chain. Proteins with more than one chain have a fourth level of structure, which describes the way in which the different polypeptide chains are arranged with respect to each other. For example, the protein shown, hemoglobin, consists of four subunits..