Lipids (fats) Main Function: long-term energy storage Special Feature: contain more energy per gram than any other biological molecule Groupings: Mostly C and H atoms(hydrocarbons) Types: 1. Triglycerides 3. Steroids 2. Phospholipids Animal fat (solid @ room temp) Plant oils (liquid @ room temp) 1 2 3 4 Which are made of which contain Carbohydrates Lipids Nucleic acids (e.g., DNA/RNA) Proteins Simple sugars (e.g., glucose) Glycerol & 3 Fatty Acids Nucleotides Amino Acids Carbon, hydrogen, oxygen Carbon, hydrogen oxygen, nitrogen, phosphorus hydrogen, oxygen, nitrogen, main function main function main function main function CATALYSIS & STRUCTURE /SUPPORT ENCODING HEREDITARY INFORMATION ENERGY STORAGE ENERGY STORAGE short-term long-term

Structure of Lipids (fats) 1 2 3 Glycerol Fatty acids

1. Triglycerides FA Glycerol FA = TG (Triglyceride) FA Structure Triglycerides are composed of 1 glycerol + 3 fatty acids (16-18 Carbons long) Formation and Breakdown Triglycerides are formed through a condensation/dehydration reaction between the glycerol and each of the fatty acids. Triglycerides are broken down into 1 glycerol and 3 fatty acids through hydrolysis 2 Types of Fatty Acids Saturated Unsaturated

Making and Breaking Lipids (fats) Fats and oils are called triglycerides because of their structure 1 Ester linkage + 3 H2O Condensation Synthesis Hydrolysis main function ENERGY STORAGE short-term

Types of Fatty Acids Saturated Unsaturated Poly - unsaturated # of Double Bonds between Carbons At least one double bond between carbon atoms None (contains maximum # of H atoms) Several double bonds

Types of Fatty Acids: Saturated Saturated Fats Solid at room temperature Contain only single C-C bonds (resulting in straight chains) During digestion these are converted into “bad cholesterol” which can clog arteries Ex. animal fats, butter

Types of Fatty Acids Fewer hydrogens – “unsaturated”

CH2-CH =CH Types of Fatty Acids BEND DUE TO DOUBLE BOND How do you think this bend affects density???

Types of Fatty Acids: Unsaturated Unsaturated Fats Liquid at room temperature Contain double C-C bonds (resulting in kinks in their chains) Unsaturated fats with more than one double bond are called polyunsaturated fats Ex. vegetable oils

Trans Fat Types of Fatty Acids Taking a perfectly good fat and making it bad! Unsaturated fat (contains double bonded carbons) that has the properties of a saturated fat Often solid at room temperature Bad for you! Also causes an increase in “bad cholesterol”

How Trans Fats Became out Enemy… Fill out the question sheet while you watch this short YouTube clip http://www.youtube.com/watch?v=2S1mQYO0g68

Phospholipids Fat derivatives in which one fatty acid has been replaced by a phosphate group and one of several nitrogen-containing molecules. an important part of the cell membrane (phospholipid bilayer)

Phospholipids Structure: Composed of glycerol, 2 fatty acids, and a phosphate-containing functional group Phosphate head is hydrophillic (water-loving) and the fatty acid tails are hydrophobic (water-hating) Why do you think the fatty acids are hydrophobic? Why is the phosphate portion hydrophillic?

The phospholipid can also be represented as: Phospholipids The phospholipid can also be represented as: Polar Head – hydrophilic (water-loving) Non-Polar Tails (fatty acids) – hydrophobic (water-hating)

Steroids Testosterone Cholesterol Very different structure to other lipids Made of 4 fused carbon rings Include hormones such as testosterone, estrogen, etc.