Lipids 1

Bellwork Explain the difference between peanut butter like Jiff or Skippy and the peanut butter bought at a natural food store like “Whole Foods” Speculate why they do not have the same texture.

Objectives Explain why fats, phospholipids and steroids are classified as lipids List the function of each lipid type Distinguish between a saturated and unsaturated fat Explain why animals primarily store energy as fat rather than carbohydrate

Key Terminology Glycerol Fatty Acid Triglyceride Saturated Unsaturated Phospholipid Amphipathic Steroid

Lipids All lipids are hydrophobic - repel water Subgroups of lipids Fats and oils Phospholipids Steroids 5

Fats and oils Made from two building blocks 1 glycerol + 3 fatty acids glycerol and fatty acids 1 glycerol + 3 fatty acids Called Triglyceride 6

A Lipid Molecule 7

Fatty acids Saturated fatty acids Unsaturated fatty acids Saturated with hydrogen no double bonds Unsaturated fatty acids has double bonds Monounsaturated one double bond Polyunsaturated – many double bonds 8

Degree of Saturation Affects the Melting Point Greater the Saturation the higher the melting point Saturated lipids (fats) have a higher melting point Solid at room temperature Ex: butter, marbling in beef Unsaturated lipids (oils) Have lower melting point Liquid at room temperature Ex: Olive oil, corn oil Biological significance Saturated fats in diet lead to heart disease (atherosclerosis) because they clog the arteries 9

Think-Pair-Share What is it about the shape of saturated fats that make them: melt at a higher temperature? clog up your arteries? Hint: think of many fat molecules grouped together. Be ready to share 3. Think-pair-share teacher presents a question teacher gives wait time for student to form answer teacher instructs students to share their answer with a partner teacher calls on non-volunteers to share with the class 3 10

Lipids: important part of animal diet Animals primarily use fat for energy storage. Why? Fat stores 9 Kcal / g of energy Kcal = Cal = 1000 cal cal = energy needed to raise 1 g of water 1 °C Carbohydrates and Proteins store only 4 Kcal / g of energy Fat also used in our bodies to Cushion vital organs like kidneys Provide insulation, especially under skin 11

Phospholipids Made from Amphipathic molecule Glycerol two fatty acids a phosphate group Amphipathic molecule a hydrophillic end a hydrophobic end 12

Biological Significance Major component of Cell Membranes Two ends of phospholipid orient themselves Hydrophillic heads next to water Hydrophobic tails next to each other to exclude water Hydrophillic heads Hydrophobic tails 13

Think-Pair-Share Why are Cell Membranes made from lipid rather than Carbs or Proteins? Be ready to share 3. Think-pair-share teacher presents a question teacher gives wait time for student to form answer teacher instructs students to share their answer with a partner teacher calls on non-volunteers to share with the class 3 14

Steroids Consists of four fused rings Biological function Examples: signal molecules Examples: Cholesterol Sex Hormones Testosterone Estrogen cholesterol testosterone estrogen 15

Anabolic Steroids Synthetic version of testosterone Mimics function of testosterone during puberty- causes buildup of muscle and bone mass Side effects: violent mood swings and deep depression acne can cause liver damage can lead to high blood pressure causing cardiovascular problems 16

Think-Pair-Share Why do athletes take Steroids? Why don’t the dangerous side effects make them decide not to take Steroids? Be ready to share 3. Think-pair-share teacher presents a question teacher gives wait time for student to form answer teacher instructs students to share their answer with a partner teacher calls on non-volunteers to share with the class 3 17

Link to Bellwork What is the difference in the Lipids that makes Jif smooth, while Whole Foods Peanut Butter has a layer of oil on top?

Write a “snapshot” of today’s learning in 50 words or less. teacher provides a prompt from the lesson students must write a “snapshot” of the lesson in 25 words or less teacher uses a strategy to check all 19