Organic Chemistry Organic compounds contain the element carbon Occur naturally only in living organisms or in their products Out of the 92 elements found in nature, only a few are in organic compounds

Inorganic compounds do not contain carbon –Exception – carbon dioxide (CO 2 ) and other carbonate compounds (CO 3 ) –Examples – water, salts, acids, bases Living organisms contain both organic and inorganic compounds –Water is the most important inorganic compound

Macromolecules Carbon atoms can be joined covalent into long chains –Straight chained molecules –Branched molecules –Ring molecules Most cells store small carbon compounds which serve as building blocks for larger molecules

Macromolecules – large molecules formed from smaller organic molecules bonded together –Four major categories: Carbohydrates Lipids Proteins Nucleic Acids Polymer – molecules made from repeating units of identical compounds (monomers) which are bonded together

Carbohydrates Composed of: –Carbon –Hydrogen –Oxygen Ratio of hydrogen to oxygen for each carbon atom (2 H : 1 O) – same as water General formula – (CH 2 O) n –N represents the number of repeating units in the chain

Carbohydrate function –Energy source –Cellular structural support Ex. Cellulose in plant walls Ex. Chitin in exoskeletons of insects

Simple sugars –Have 3-7 repeating units –Also known as a monosaccharide –Chemical names ALWAYS end in -ose –Ex. Glucose (C 6 H 12 O 6 ) – essential energy source for organisms

Disaccharide –Two simple sugars linked together –Ex. Sucrose (table sugar) – additional energy source for organisms –Ex. Lactose – component of milk

Dehydration Synthesis – sugar molecules are bonded together by removing water –Brought on in living cells by the action of enzymes –Important in forming the complex organic compounds an organism needs

Polysaccharide –Three or more simple sugars linked together (polymer) –Ex. Glycogen – molecule form for storage of glucose found in liver and skeletal muscle

Hydrolysis –Breakdown of disaccharides or polysaccharides to yield simple sugars

Lipids Composed of: –Carbon –Hydrogen –Oxygen (less than found in carbohydrates) Triglycerides: –Fats Solid at room temperature –Oils Liquid at room temperature –Waxes

Contains fatty acids and glycerol components –Glycerol – 3 carbon chain with an OH group bonded to each carbon –Fatty acid – chain of carbon atoms with a hydrogen or a carboxyl (-COOH) group bonded to each carbon Dehydration (loss of water) combines 3 fatty acid molecules and 1 glycerol molecule to produce a fat or oil molecule

Primary function – reserve of stored energy Examples: –Stored in fat cells of your body –Used on leaves as waxes to prevent water loss –Used to compose structural elements like honeycomb in a beehive (beeswax)

Saturated versus unsaturated fats: –Lipids can contain single or double bonds –Saturated fats Solid at room temperature (fats or waxes) Contain SINGLE bonds between carbon atoms

–Unsaturated fats Contain DOUBLE or TRIPLE bonds between carbon atoms Liquids at room temperature (oils) Polyunsaturated – more than one double bond –Doctors recommend more unsaturated and less saturated fats in your diet

Phospholipids –Plasma membrane component –Have hydrophobic and hydrophilic regions Steroids –Building block for vitamin D and large hormones like testosterone and estrogen –Ex. Cholesterol

Proteins Composed of –Carbon –Hydrogen –Oxygen –Nitrogen

Amino Acids –Building block of a protein –Consist of a central carbon atom bonded to 1 carboxyl group (COOH) 1 amino group (NH 2 ) 1 hydrogen atom 1 side chain (R) – different for every amino acid –20 different amino acids Simplest  glycine (side chain is H) Alanine  CH 3 side chain

Peptide Bond –Bond used to connect two amino acids together through dehydration synthesis –Forms between the amino group (-NH 2 ) of one amino acid and the carboxyl group (-COOH) of another, resulting in the loss of one water molecule

–Resulting molecule is called a dipeptide –Long chains of amino acids are called polypeptides –All proteins are made of one or more polypeptides bonded together

Protein structure (four levels) –Primary Depends on what amino acids are used and how many –Secondary Amino acid chain can fold into a helix or pleat –Tertiary Considered to be globular or form long chains –Quaternary Combination of long polypeptide chains to form a protein

The first protein structure identified was insulin, a hormone that controls blood glucose levels (1954)

Protein Function –Make up 15% of your body mass (10,000 different proteins in a single cell!) –Involved in almost every function of your body Structural support Cellular transport Cell communication Speeding up chemical reactions Cell growth –Ex. Muscle, skin, hair, enzymes, hormones, antibodies

Nucleic Acids Composed of –Carbon –Hydrogen –Oxygen –Nitrogen –Phosphorus Function –Store and transmit genetic information

Nucleotides –Basic structural unit –Contain a phosphate group (PO 4 ), nitrogenous base and a 5-carbon sugar (ribose or deoxyribose)

–Nitrogenous base is an organic base which contains nitrogen Four types: –Adenine –Thymine –Cytosine –Guanine –Attached in a sequence along the length of the molecule (even up to 3 billion pairs!)

Two forms of nucleic acids in living things –DNA – Deoxyribonucleic acid Hereditary material that is passed on from generation to generation through reproduction –RNA – Ribonucleic acid Found within the cells nucleus –Directs and controls the development and activities of all the cells in an organism

Structure of DNA –Resembles the shape of a ladder Two sides (sugar- phosphate backbone) connected to each other by rungs (nitrogenous bases) –Double stranded

–Sugar used is deoxyribose –DNA molecule is coiled into the form of a double helix One human DNA molecule if stretched out straight could be 4 cm long!

Structure of RNA –Similar in chemical composition to DNA but consists of only one chain of bases attached to a sugar-phosphate backbone –Sugar used is ribose –The base thymine is replaced by uracil –RNA is involved in protein synthesis

Main Ideas Carbon compounds are the basic building blocks of living organisms Biological macromolecules are formed by joining small carbon compounds into polymers There are four types of biological macromolecules Peptide bonds join amino acids in proteins Chains of nucleotides form nucleic acids