Chapter 5: The Structure and Function of Large Biological Molecules

3 Main Questions:
- What are the four main classes of large biological molecules?
Carbohydrates, lipids, proteins, and nucleic acids.
- How many level of protein structure are there?
There are four levels of protein structure: primary , secondary, tertiary quaternary.
- What is fat ?
Fat is constructed from two kinds of smaller molecules: glycerol and fatty acids.

5 Main Facts:
- Carbohydrates include both sugars and polymers of sugars.
- Monosaccharides, particularly glucose, are major nutrients for cells.
- In making a fat, 3 fatty acid molecules each join to glycerol by an ester linkage, a bond between a hydroxyl group and a carboxyl group.
- Fatty acids vary in length and in the number and locations of double bonds.
- Many hormones, as well as cholesterol, are steroids, which are lipids characterized by a carbon skeleton consisting of four fused rings.

Diagrama) One water molecule is removed for each fatty acid joined to the glycerol.
b) Three fatty acid molecules each join to glycerol by an ester linkage, a bond between a hydroxyl and a carboxyl group. The carbons of the fatty acids are arranged zig-zag to suggest the actual orientations of the four single bonds extending from each carbon.

Summary
There are four important molecules of all living things: carbohydrates, lipids, proteins, and nucleic acids. 3 of those molecules, carbohydrates, proteins, and nucleic acids are called macromolecules because of their huge size. Carbohydrates include both sugars and polymers of sugars.
The compounds lipids are grouped together because they shared one important trait. They mix poorly with water. Phospholipids are essential for cells because they make up cell membranes. Polymers of amino acids are called polypeptides.

Video
http://www.youtube.com/watch?v=E2-FSHTc3U8&feature=related

10 Key Terms:
- Polymer: a long molecule consisting of many similar or identical building blocks linked by covalent bonds.
- Monomers: the repeating units that serve as the building blocks of a polymer.
- Enzymes: specialized macromolecules that speed up chemical reaction in cells.
- Hydrolysis: a process that is essentially the reverse of the dehydration reaction.
- Monosaccharide: the simplest carbohydrate, active alone or serving as a monomer for disaccharides and polysaccharides.
- Disaccharide: a double sugar, consisting of two monosaccharides joined by a glycosidic linkage formed during dehydration sunthesys.
- Lipid: one of a group of compounds, including fats, phospholipids, and steroids, that mix poorly, if at all, with water.
- Fat: a lipid consisting of three acids linked to one glycerol molecule.
- Phospholipids: essential for cells because they make up cell membranes.
- Unsaturated fatty acid: formed by the removal of hydrogen atoms from the carbon skeleton.