Transcript Metabolism
1. 2. 3. 4. Cellular respiration Fermentation Metabolism BMR Carbohydrate Metabolism • The body’s preferred source to produce cellular energy (ATP) • Glucose (blood sugar) is the major digestive product and serves as fuel to make ATP Figure 14.17 Metabolic Pathways Involved in Cellular Respiration Figure 14.18 Glycolysis harvests chemical energy by oxidizing glucose to pyruvic acid Glucose Pyruvic acid Figure 6.9A Energy yield: 2 ATP and 2 NADH Pyruvic acid is altered for the citric acid cycle Pyruvic acid Acetyl CoA (acetyl coenzyme A) CO2 Figure 6.10 The citric acid cycle completes the oxidation of organic fuel Acetyl CoA • enzymes convert acetyl to CO2 and generate NADH and FADH2 molecules CITRIC ACID CYCLE Figure 6.11A 2 CO2 Steps in the Electron Transport System 1. Set up H+ gradient using energy of e- from NADH, FADH2 2. Downhill flow of H+ is used to make ATP Figure 3.28 cell outer membrane inner membrane mitochondrion • An overview of cellular respiration High-energy electrons carried by NADH GLYCOLYSIS Glucose Cytoplasmic fluid Figure 6.8 Pyruvic acid CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS Mitochondrion Fermentation is an anaerobic alternative to aerobic respiration • Without oxygen, cells can use glycolysis alone to produce small amounts of ATP – But a cell must replenish NAD+ Glucose Pyruvic acid • In lactic acid fermentation, pyruvic acid is converted to lactic acid – NAD+ is recycled • Contributes to muscle soreness GLYCOLYSIS 2 Pyruvic Glucose Figure 6.15B acid 2 Lactic acid • Pathways of molecular breakdown Food, such as peanuts Polysaccharides Fats Proteins Sugars Glycerol Fatty acids Amino acids Amino groups Glucose G3P GLYCOLYSIS Figure 6.16 Pyruvic acid Acetyl CoA CITRIC ACIDS CYCLE ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS • Biosynthesis of macromolecules from intermediates in cellular respiration ATP needed to drive biosynthesis CITRIC ACID CYCLE GLUCOSE SYNTHESIS Acetyl CoA Pyruvic acid G3P Glucose Amino groups Amino acids Fatty acids Glycerol Sugars Proteins Fats Polyscaccharides Cells, tissues, organisms Figure 6.17 Body Energy Balance • Energy intake = total energy output (heat + work + energy storage) – Energy intake from food oxidation • Proteins, carbs have 4 Cal/gm • Fats have 9 Cal/gm – Energy output • Heat is usually about 60% • Storage energy is in the form of fat or glycogen Regulation of Food Intake • Body weight is usually relatively stable – Energy intake and output remain about equal • Mechanisms that may regulate food intake – – – – Levels of nutrients in the blood Hormones: leptin, ghrelin Body temperature Psychological factors Metabolic Rate and Body Heat Production • Basic metabolic rate (BMR) reflects the amount of energy spent per unit of time by a body at rest • Factors that influence BMR: – Body shape (height and weight), gender, body composition, age, stress, food intake, genetics • TMR = Total Metabolic Rate – Total energy spent, includes activity above BMR Estimation of BMR • Johnson: your weight in kg (# lbs/2.2) x 24 (x 0.9 if female) = Calories per day • Your weight in kg (# lbs/2.2) x % lean mass males usually 82-88% females usually 75-82% Then check table (next slide) ESTIMATION OF RESTING METABOLIC RATE (RMR) BASED ON FAT-FREE BODY MASS (FFM) FFM (kg) RMR (kcal) FFM (kg) RMR (kcal) FFM (kg) RMR (kcal) 30 31 32 33 34 35 36 37 38 39 40 1018 1040 1061 1083 1104 1126 1148 1169 1191 1212 1234 58 59 60 61 62 63 64 65 66 67 68 1623 1644 1666 1688 1709 1731 1752 1774 1796 1817 1839 86 87 88 89 90 91 92 93 94 95 96 2228 2249 2271 2299 2314 2336 2357 2379 2400 2422 2444 41 42 43 44 45 46 47 48 49 50 1256 1277 1299 1320 1342 1364 1385 1407 1428 1450 69 70 71 72 73 74 75 76 77 78 1860 1882 1904 1925 1947 1968 1990 2012 2033 2055 97 98 99 100 101 102 103 104 105 106 2465 2487 2508 2530 2552 2373 2595 2616 2638 2660 51 52 53 54 55 56 57 1472 1493 1515 1536 1558 1580 1601 79 80 81 82 83 84 85 2076 2098 2120 2141 2163 2184 2206 107 106 109 110 111 112 113 2681 2703 2724 2746 2768 2789 2811