10.9.13 Kin 110 class notes- Which is more economical fuel (more miles per gallon) – CHO or fat?o Poptartso Butter- Fat (lipid) contains energy in carbon bondso Break bonds – release energy- Lipids can be oxidized to CO2 and H2O to produce ATP:o Fatty acidso Structure: HOO –C-C-C-C-C-C-C-C-C-C etco Palmitate: fatty acid (most common in human metabolism- Fatty acids stored in plants and animals as triglycerides- Where is fat stored?o Adipose tissue (fat tissue)o Subcutaneous (under the skin )o Fat= main storage areao Visceral fat mainly in abdomen around organs_ Strongly related to diabetes, CVD, hypertension- More visceral fat = lower sensitivity to insulino High is goodo Insulin sensitivity vs % central abdominal fat- Large-volume liposuctiono Removed 20 lbs fat from abdominal area- Before:o Subcutaneous fat removedo 20 lbs abdominal fat sucked outo LDL cholesterol, insulin sensitivity, triglycerides etc – nothing happened!o Didn’t improve health (risk factors for diabetes, heart disease)o Removing the fat - To use energy in fato 1. Mobilization stress hormones (adrenaline, epinephrine) into the blood ( TG fatty acids) stored triglycerides and sent to blood (fatty acids)o 2. Uptake FA taken up from blood muscle Higher FA in blood = more taken up by muscleo 3. FA into mitochondria carnitine – chaperones fatty acids into mitochondria cytosolo 4. FA to acetyl CoA FA sliced to unit 16 carbon FA 8 acetyl CoAo 5. Oxidation of acetyl CoA for energy: products are carbon dioxide, H2O + 129 ATP TCA Krebs Acetyl CoA 129 ATP (cycle)- Oxidation of fat releares a lot of ATPo BUT 1. Relatively slow (5 steps)- mobilization- uptake by muscle- entry into mitochondria- slicing to acetyl CoA- oxidation for energy- 2. Requires a lot of oxygeno 46 oxygen to oxidize palmitate to CO2 and H2O atomso only 12 oxygen atoms to oxidize glucose to Co2 and H2O- Which fuel is more economical?o Glucose Cho: 36 ATP and requires 12 oxygen 3.0 ATP per O2o palmitate (fat) produces 129 ATP and requires 46 oxygen = 2.8 ATP per oxygen- energy per carbon atom?o CHO = 36 ATP/6 carbon = 6 ATP/carbon atomo FAT = 129 ATP/16 carbons = 8 ATP/carbon atom- Storage?o To store 90,000 kcal of energy:o As glycogen: 90,000/4 kcal/g = 22,500 g = 22.5 kg = 49 lbso As fat: 90,000/9 kcal/g = 10.0 kg = 22 lbo 27 lbs less storing energy as fat
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