Chapter Three

Key terms:
Organic Compounds: Carbon based molecules.
Carbon Skeleton: chain of carbon atoms in an organic molecule.
Hydrocarbons: compounds composed of only carbon and hydrogen.
Isomers: Compounds with the same formula but different structures.
Macromolecules: molecules that are gigantic.
Polymers: A long molecule consisting of many identical or similar building blocks strung together.
Monomers: The building blocks of polymers.
Dehydration reaction: a reaction that removes a molecule of water that link monomers together to form a polymer.
Hydrolysis: cells break bonds between monomers by adding water to them; reverse dehydration reaction.
Enzymes: specialized macromolecules that speed up chemical reactions in cells.

Reading Journal:
1) What is Lactose intolerance? Lactose intolerance is when people do not have an enzyme called lactase to help break down the lactose.
2) What are the main types of large molecules? Proteins, Lipids, Carbohydrates, and Nucleic Acids.
3) What are the four levels of Protein Structure? First is the Primary structure, which is the simplest; second is the Secondary Structure, which is either an alpha helix or a pleated sheet; third is the Tertiary strcture, which all of the proteins are in a globular like, three dimensional shape; and Quaternary, are when four globular three dimensional shapes are cluttered together.

Five Facts:
1) Linus Pauling and his colleagues discovered how oxygen molecules attach to the iron atoms of hemoglobin in 1935.
2) Monosaccharides are carbohydrate monomers. Polysaccharides are monosaccharides are just polymers of monosaccharides linked together by dehydration reaction.
3) Dehydration reaction is used to link monomers together to form polymers.
4) Phospholipids contain only two fatty acids attached to glycerol instead of three.
5) Anabolic steroids are synthetic variants of the male hormone testosterone. They are also used to treat general anemia and other illnesses that may destroy the body muscle.

Many of the molecules that a cell makes are composed of carbon. The carbon atoms are bonded to other element's atoms to make different combinations. Carbon based molecules are called organic compounds. Compounds that are only composed of hydrogen and carbon are called hydrocargons. Their carbon skeletons may vary in length, be branched or unbranched, have double bonds, and/or arranged in rings. There are different functional groups of organic compounds and are considered hydrophillic (water-lovin'). Hydroxyl group consists of hydrogen and oxygen. A carbonyl group is a carbon atom linked by a double bond to an oxygen atom. A carboxyl consists of a carbon double bonded to an oxygen and a hydroxyl group. An amino group is composed of a nitrogen bonded to hydrogen atoms and the carbon skeleton. A phosphate group contains phosphorous to four oxygen atoms. a methyl group contains a carbon bond to three hydrogens. Macromolecules are just big molecules. A polymer is a long molecule consisting of monomers. they are linked together by a dehydration reaction, which just removes a molecule of water to attach together. Hydrolysis breaks the polymers by adding water.
Monosaccharides are the simplest carbohydrates. Monosaccharides are just single unit sugars and are the main fuel molecules for cellular work. A disaccharide are just two monosaccharides that are formed by a dehydration reaction. The most common disaccharide is sucros. Polysaccharides are polymers of monosaccharides linked together by dehydration reactions. Some examples are starch, glycogen, cellulose, and chitin.
Lipids are diverse compounds that are grouped together because they mix poorly with water. Lipids are hydrophobic (water hatin'). Their main function is to store energy. Fatty acids and fats that have double bonds are considered unsaturated, having less than the max number of hydrogens. Those with the max number of hydrogens are saturated. Phospholipids are structurally simlar to fats, but contain only two fatty acids instead of three. They have a hydrophillic head and hydrophobic tails.
Protein is a polymer constructed from amino acid monomers. Proteins are important to the structures of cells and organism and participate in everything they do. Enzymes are specialized macromolecules that are catalysts that speed up chemical reactions in cells. Proteins are made from amino acids linked by peptide bonds. A peptide bond is a covalent linkage. Two aminos acids are dipeptide bonds. A chain of amino acids are polypeptide. Denaturationis when polypeptide chains unravel and lose their specific shape and function.

There are four different levels of protein structure: Primary, Secondary, Tertiary, and Quaternary structure.
Primary: The simplest structure, is a unique structure of amino acids.
Secondary: There are basically two forms of secondary structure, helix (shown), and pleated sheet (not shown).
Tertiary: It is a three dimensional shape of a polypeptide.
Quaternary: A complete transthyretin molecule with four identical globular subunits.


Video Link Dehydration and hydrolysis:
http://www.youtube.com/watch?v=fOcffAxZwC0&feature=related