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Lipids

Fats, Oils and Waxes. Lipids. Lipid Basics. Lipids are made mostly from carbon and hydrogen They are hydrophobic and don’t dissolve in water Composed of glycerol + fatty acid monomers Most common lipids are fats, oils, and waxes. Fatty Acids. 2 types – saturated and unsaturated

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Lipids

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  1. Fats, Oils and Waxes Lipids

  2. Lipid Basics • Lipids are made mostly from carbon and hydrogen • They are hydrophobic and don’t dissolve in water • Composed of glycerol + fatty acid monomers • Most common lipids are fats, oils, and waxes

  3. Fatty Acids • 2 types – saturated and unsaturated • - What’s the difference? - saturated fatty acids contain no double bonds between Carbon atoms - holds the maximum # of H atoms (saturated with hydrogen) - unsaturated fatty acids contain double bonds between Carbon atoms

  4. Saturated Fats • Found in animal products like bacon, whole milk, ice creams, fatty meats • They are a solid at room temperature • Tends to increase the amount of cholesterol in your body, which also increases your risk for heart attack and stroke by clogging arteries

  5. Unsaturated Fats • Found in plant products like canola oil, avocados, and nuts. • Tends to be a liquid at room temperature • Raises levels of good cholesterol in your body

  6. Lipids – Types and Functions • Fats/Oils – long term energy storage, insulation and protection • Phospholipids – cell membranes • Steroids – make hormones (chemical messengers) • Waxes – waterproofing

  7. Lipids – Fats and Oils • Fats & Oils (triglycerides)- provide long term energy storage • Fat has twice the calories of carbohydrates. • fat = 9 cal/g sugar= 4 cal/g • Lipids have more calories because they have more C – H bonds which store energy

  8. Body Fat – stores energy, insulates and protects the organs Excess energy not used or burned off is converted to fat Sea mammals rely on fat to keep them warm

  9. Lipids function to form cell membranes • Glycerol • only 2 fatty acids (not 3 like fats and oils) • 3rd fatty acid is replaced by a phosphate molecule SPONCH

  10. + CH2 Choline N(CH3)3 CH2 O Phosphate Hydrophilic head – P O O O CH2 CH2 CH Glycerol O O C O C O Fatty acids Hydrophilic head Hydrophobic tails Hydrophobic tails (c) Phospholipid symbol (b) Space-filling model Figure 5.13 (a) Structural formula • Phospholipid structure • Phosphate molecule forms a hydrophilic (water loving) head • Fatty acid molecules make up a hydrophobic tails

  11. WATER Hydrophilic head WATER Hydrophobic tail • Phospholipids create the structure of cell membranes • 2 layers of phospholipids • Phosphates face out – interact with water • Lipid tails make a middle layer that repels • water • Phospholipids separate the contents of the cell from it’s surrounding environment

  12. Myelinsheaths - phospholipid that insulates nerve cells and functions to increase the rate at which nerve signals are sent We are all literally “Fatheads”

  13. What happens when myelin sheath deteriorates? • Multiple sclerosis (MS) is an autoimmune disease where the body attacks and destroys the myelin around the nerve cells • Results in: weakness, double vision, urinary problems, problems with bowel movements, tremors, tingling and numbness

  14. Lipids- Cholesterol • Looks like connected rings of carbon • Is a component of the cell membrane – adds to the integrity (structure) of the membrane

  15. Two types of cholesterol • (1) Low density lipoprotein (LDL) – Bad cholesterol – circulates in blood and gradually builds up plague in arteries • (2) High density lipoprotein (HDL) – Good cholesterol - tends to carry cholesterol away from the arteries and back to the liver, where it's passed from the body. Some experts believe that HDL removes excess cholesterol from arterial plaque, slowing its buildup.

  16. Steroids: Lipids that act as Hormones • Cholesterol used to make steroids • Hormonesare chemical messengers - produced in one part of the body, they travel to and cause changes in another part of the body - Hormones control: growth development tissue function sexual function the way our bodies use food, the reaction of our bodies to emergencies, mood - examples estrogens testosterone Estrogen Testosterone

  17. Waxes-Lipids that repel water - found on the surface of leaves…why? - found on animal hair to keep it pliable - found on the feathers of water birds to prevent them from becoming waterlogged (waterproofing)

  18. Tests to detect the presence of lipids… • Grease spot test – Place substance on brown paper bag. Allow spots to dry, if lipid is present a translucent spot will be left behind.

  19. Flashcards for Your Learning Pleasure • lipid basics • saturated fatty acids • unsaturated fatty acids • hydrophobic • hydrophilic • fats • oils • phospholipids • myelin • cholesterol • steroids • hormones • waxes

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