24.3 ATP and Fatty Acid Oxidation Marine mammals have thick layers of blubber that serve as insulation as well as energy storage. A camel stores large amounts of fat in its hump. Learning Goal Calculate the total ATP produced by the complete oxidation of a fatty acid.

ATP from Fatty Acid Oxidation The energy yield from a fatty acid changes with the number of β oxidation cycles needed for its oxidation. Each cycle requires an initial input of two ATP. produces an NADH, an FADH2, and one acetyl CoA. NADH generates energy for the synthesis of 2.5 ATP. FADH2 provides energy for the synthesis of 1.5 ATP. Each β oxidation cycles produces 4.0 ATP. produces one acetyl CoA that enters the citric acid cycle, generating 10 ATP. Core Chemistry Skill Calculating the ATP from Fatty Acid Oxidation (β Oxidation)

ATP from β Oxidation, Capric Acid

Chemistry Link to Health: Stored Fat and Obesity The storage of fat is an important survival feature used by animals. Some animals store large amounts of fat to supply energy for their hibernation period. Camels store large amounts of fats in their humps, allowing them to survive months without food or water. Whales have a thick layer of fat, or blubber, providing them with warmth and energy so they can survive for long periods without food.

Chemistry Link to Health: Stored Fat and Obesity Humans have the capability to store large amounts of fat. used to survive on sparse diets that were mostly vegetarian; about 20% of the dietary calories were from fat. have diets today that include more dairy products and foods with high fat levels, and as much as 60% of their calories are from fat. The U.S. Public Health Service now estimates that in the United States more than one-third of adults are obese.

Chemistry Link to Health: Stored Fat and Obesity Obesity is defined as a body weight that is more than 20% over an ideal weight. Obesity is a major factor in health problems such as diabetes, heart disease, high blood pressure, stroke, and gallstones. occurs when the energy intake (calories in food) is more than the energy expended (calories used by the body).

Chemistry Link to Health: Stored Fat and Obesity, Ghrelin Body weight and food intake are regulated by two “hunger hormones” called ghrelin and leptin. Ghrelin, an appetite-stimulating hormone of 28 amino acid residues, is secreted by an empty stomach and travels to the brain, where it makes you feel hungry. stops secretion when the stomach is stretched. In people with a high calorie intake, the ghrelin levels are low, whereas in people who are fasting, the ghrelin levels are high.

Chemistry Link to Health: Stored Fat and Obesity, Leptin Leptin is a protein secreted mainly in the fat cells that travels to the brain and makes you feel full. Leptin levels increase with an increase in adipose tissue. are high when patients are obese. act on the liver and skeletal muscles, where high levels stimulate fatty acid oxidation in the mitochondria, decreasing fat stores. Obese patients may be leptin-resistant, which means that they do not experience a sense of fullness. Leptin, shown here as a ribbon model, is an appetite-repressing hormone that consists of 146 amino acid residues formed in the fat cells.

Study Check What is the total ATP produced from the β oxidation of stearic acid (C18)? A. 108 ATP B. 120 ATP C. 148 ATP

Solution What is the total ATP produced from the β oxidation of stearic acid (C18)? B. 120 ATP Activation –2 ATP 9 Acetyl CoA × 10 ATP 90 ATP 8 NADH × 2.5 ATP 20 ATP 8 FADH2 × 1.5 ATP 12 ATP 120 ATP