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Regents Biology 2003-2004

Lipids: Fats & Oils

Regents Biology 2003-2004

Lipids Concentrated energy molecules

Regents Biology 2003-2004

Lipids § Examples

u fats u oils u waxes u hormones synthesized from

cholesterol (in gonads and adrenal glands, also called “steroids”) § Includes sex hormones

w testosterone (male) w estrogen (female) Regents Biology 2003-2004

Lipids

§  Function: u energy storage

§  very concentrated §  twice the energy as carbohydrates!

u cell membrane u cushions organs u  insulates body

§  think whale blubber!

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Regents Biology 2003-2004

Structure of Fat not a chain (polymer) = just a “big fat molecule”

Regents Biology 2003-2004

Saturated fats § Most animal fats

u solid at room temperature

§  Limit the amount in your diet u contributes to

heart disease u deposits in

arteries

Regents Biology 2003-2004

Unsaturated fats § Plant, vegetable & fish fats

u  liquid at room temperature §  the fat molecules

don’t stack tightly together

§ Better choice in your diet

Regents Biology

Cis and Trans Unsaturated Fats

2003-2004

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Regents Biology

Also in the news: Omega 3 and 6

2003-2004 Regents Biology

Balance of Omega 6 to 3

§  Ideal diet is a ratio less than 4:1 (maybe closer to 1:1), similar to our ancestors. (NIH)

§ Western diet ratio is closer to 15:1. § High omega 6 to 3 ratio promotes many

diseases (cardiovascular, cancer, inflammatory autoimmune and even mental illness)

§  Low omega 6 to 3 ratio has suppressive effects on the above diseases

2003-2004

Regents Biology

How to change your ratio §  Look for foods with lower ratio of 6 to 3

u Replace almonds (only omega 6) with walnuts (4:1)

u Replace olive oil (10-13:1) with flax seed oil (0.3:1)

u Lots of greens have ratios less than 4:1 u Corn is high in omega 6, so replace corn-

fed beef (9-13:1) with grass fed (2-3:1) u Wild rice is a grass (1.25:1)

2003-2004 Regents Biology

Sustainable seafood high in omega 3

§ Monterey Bay Aquarium “Best Choice” u Low in mercury, high in omega 3,

caught or farmed responsibly u Atlantic Mackerel u Freshwater Coho Salmon (US farmed) u Pacific Sardines (wild) u Salmon (Alaskan wild)

2003-2004

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Regents Biology 2003-2004

Other lipids in biology § Cholesterol

u Critical in cell membranes u make hormones from it

§  including sex hormones u but too much cholesterol in blood may

lead to heart disease u Ratio of LDL (low density lipoproteins:

bad) to HDL (good) is important

Regents Biology 2003-2004

Other lipids in biology § Cell membranes are made out of lipids

u Phospholipids (and cholesterol) u heads are on the outside touching water

§  “like” water u  tails are on inside away from water

§  “scared” of water u  forms a barrier

between the cell & the outside

Regents Biology

The unique layered structure of cell membranes is due to A. protein B. cholesterol C. cellulose D. phospholipids

Regents Biology

Review Questions 1.  What are some examples of lipids? fats, oils, waxes, steroid hormones 2. What are some functions of lipids? energy storage, cell membranes, cushions organs, insulates 3. What are some characteristics of saturated

fats? C’s are full of H’s, solid at room temp, raises bad cholesterol (LDL)

2003-2004

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Regents Biology

Review Questions 4. What are some characteristics of

unsaturated fats? Have double bonds, kink, and are liquid at room temp 5. What is the structural difference between

cis and trans fats? Cis have H on the same side of the double bond. Trans have H on opposite sides of the double bond

2003-2004 Regents Biology

Review Questions 6. What is “bad” about trans fats? more like saturated fat, increases LDL (good) and lowers HDL (bad) 7. What is ideal ratio of omega 6 to 3

consumption? less than 4:1 8. What are some foods with a lower ratio of

omega 6 to 3? walnuts, flax seed oil, certain fish

2003-2004