University:
Amherst College
Course:
BIOL 191 | Molecules, Genes and Cells
Academic year:

2011
Views:

120

Pages:

19
Author:

sklepatilay

Biological Building Blocks II What are we made of? • Chemical Bonds – Covalent and Ionic • Important Biological Molecules – Carbohydrates – Lipids: Fats and Membranes • Energy storage and compartmentalizaKon – Amino Acids • Building blocks of proteins/enzymes – Nucleic Acids • Building blocks of DNA and RNA Anatomy of Fat O O • Triglycerides O • Glycerol OH HO • Hydrocarbon Tails – Each from a faQy acid O HO O O – A type of lipid HO O ObservaKons 1. Oil (a fat) and water do not mix 2. Fats can be liquid or solid – BuQer vs. Olive oil at room temperature 3. Soap can be made from fat, but mixes with water ObservaKons 1. Oil (a fat) and water do not mix 2. Oil is liquid, buQer is solid – At room temperature 3. Soap can be made from fats, but mixes with water Why don’t they mix? 1. Water likes to make “hydrogen bonds” with itself – Non-‐covalent – Weaker interacKon than covalent bond 2. Hydrophobic Eﬀect – Non-‐polar atoms sKck together Non-‐covalent interacKons • Water molecules interact by Hydrogen Bonds – Polar interacKon • Hydrocarbons interact by Van der Waals forces – Also called London Dispersion forces – Non-‐polar interacKon ObservaKons 1. Oil (a fat) and water do not mix 2. Fats can be liquid or solid – BuQer vs. Olive oil at room temperature 3. Soap can be made from fat, but mixes with water Solid vs. Liquid • Solids: molecules are Kghtly held together – Intermolecular forces strong • Liquids: molecules are sKll aQracted to each other, but can ﬂow • Gas: molecules have enough energy to break free from each other MelKng points of FaQy Acids ObservaKons 1. Oil (a fat) and water do not mix 2. Fats can be liquid or solid – BuQer vs. Olive oil at room temperature 3. Soap can be made from fat, but mixes with water What happens chemically to fats when turned to soap? • SaponiﬁcaKon – NaOH added to triglycerides • ReacKon frees faQy acids from glycerol • FaQy acids are the key component of soap FaQy Acid Structure • FaQy Acids are made up of – an acid group(-‐COOH) – a hydrophobic group (CnHm) – Makes these molecules: • Amphiphilic FaQy Acids in Water FaQy Acids with oil and water Lipid Membranes • Composed primarily of phospholipids FaQy acids are used to make Phospholipids – components of cell membranes Plasma Membranes are made of phospholipids • Phospholipids: form a bilayer to make cell membrane • FLUID MOSAIC MODEL: Lots of things are embedded in membrane Phospholipids in water

Biological Building Blocks II

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