BIBC 120 - Lipid Lecture

BIBC 120 - Lipid Lecture - BIBC 120(Lipids Lipids...

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BIBC 120 (Lipids) Lipids: hydrocarbons – so they have less oxygen and therefore greater caloric value. Lipids are also hydrophobic and thus tend to clump together, especially in water Fats taste good as an evolutionary adaptation. Because fats are used for stored energy, it used to be important to eat fat whenever possible so as to have it in situations when food is not available. Function of fats o Provide energy for immediate and storage use ~50% of immediate energy is being provided by fats Fat is stored in adipocytes. o Insulation – subcutaneous fat under our skin keeps us warm Elderly people tend to lose body fat in the form of subcutaneous fat and are therefore more prone to feeling cold Anorexic – don’t have subcutaneous fat, but instead develop very fine hairs called lanugo. Lanugo keeps a person warm because muscles under the hair follicles tighten and trap air which allows for modulation of temperature. o Cell membranes utilize fat – includes phospholipids and cholesterol o Protection/Cushioning – body organs are protected by a layer of fat o Fat serves as a vehicle for fat soluble vitamins and aid in their absorption. FAT OIL - Solid at room te mp erature - Liquid at room te mp erature - Saturated – m e dium/short chain - MUFA/ PUFA - Animal fat - Tropical plants – coconut oil a nd p almoil - Vegetables, with the exception of fish oil Sterol : a compound containing a m ulti-ring (steroid) structure and a hydroxyl group (-OH) Characterized a s a lipid bec aus e does not dissolve in water Acetyl-CoA (derived from acetic acid) is building block of cholesterol Found from a nim al sources (eggs and m e at) – not found in plants Importance of Cholesterol 1. Gives flexibility to cells because it is found in membranes 2. Building blocks for hormones, such as estrogens, testosterones 3. Precursor to vitamin D. Body is synthesizing this vitamin by utilizing cholesterol and UV light. 4. Cholesterol is a component of bile, which are needed during fat digestions.
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a. High levels of fat/ cholesterol consumption means a lot of it is made into bile. This build up of cholesterol in the bile makes it very concentrated, which can lead to gallstones. 5. Cholesterol is important in packaging VLDL and chylomicrons, which are methods in which lipids are transported in the blood – this is linked to cardiovascular disease In our body, organs are going to have higher levels of cholesterol. For example, the brain has 2640 mg of cholesterol. This is because cholesterol is the sheath surrounding the nerve cells,
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This note was uploaded on 10/12/2009 for the course BIBC BIBC120 taught by Professor Chilukuri during the Spring '08 term at UCSD.

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BIBC 120 - Lipid Lecture - BIBC 120(Lipids Lipids...

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