1. Lipids 1

2. 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.

3. 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

4. Key Terminology Glycerol Fatty Acid Triglyceride Saturated Unsaturated
Phospholipid
Amphipathic
Steroid

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

6. 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

7. A Lipid Molecule 7

8. 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

9. 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

10. 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

11. 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

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

13. 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

14. 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

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

16. 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

17. 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

18. 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?

19. 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