BMR of metabolism


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BMR is the required an awake individual during physical, emotional and digestive rest.

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  • Refs in text
    Ch 3.7
    Ch 3.7
    P335, Fig 14.15
    Ch 14.11
  • Glucose is the ONLY energy source for the CNS.
    Oxygen-using events take place within the cell to create ATP from ADP
    Carbon leaves cells as carbon dioxide (CO2)
    Hydrogen atoms are combined with oxygen to form water
    Energy produced by these reactions adds a phosphorus to ADP to produce ATP
    ATP can be broken down to release energy for cellular use
  • 3 stages - note ATP production in each stage.
    Glycolysis - small amount of ATP 2. Works even without O2. Anaerobically in muscles.
    NAD taxi filled.
    Krebs cycle - CO2 released here. What we exhale.
    a bit more ATP 2. And more high-energy electrons. Fill the taxi with e- passengers. Shuttle over to electron transport chain.
    ETChain. Slinky on stairs. Stepwise release of chemical energy. Captured in ATP 36. E passed to O2 to make water. So, this process needs oxygen. What we breathe in.
  • Each pyruvic acid molecule is broken down to form CO2 and a two-carbon acetyl group, which enters the citric acid cycle
  • Rotenone binds to ETS carrier. Used to kill pest insects and fish. Similar blockage with cyanide and carbon monoxide. Shuts off “faucet” of ATP synthesis. Cells starve to death. Oligomycin blocks H+ from flowing thru ATP synthase. Used as antifungal agent on skin. Does not hurt dead skin cells on surface. Keratin keeps it from penetrating into living skin cells in deeper layers.
    Uncouplers, Dinitrophenol, 1940s weight loss pill. Fuel is burned, but no ATP generated. Leads to death.
  • Figure: 07-06a Note the extra surface area provided by folds of inner membrane. More enzymes of ETS can be held. Note relatively smaller volume of intermembrane space, making it easier to create a large concentration gradient of H+.
    Mitochondria are organelles, or “tiny organs,” that exist within cells. They are the location for the second and third sets of steps in cellular respiration, the Krebs cycle and the electron transport chain. Following a transitional step (see Figure 7.7), the products of glycolysis—the downstream products of the original glucose molecule—pass into the inner compartment of a mitochondrion, where the Krebs cycle takes place. Electrons derived from the Krebs cycle then migrate, via electron carriers, from the Krebs cycle site into the highly folded inner membrane of the mitochondrion, where the bulk of ATP is produced in the electron transport chain.
  • 2/2/32 ATP from each stage. Aerobic respiration much more efficient at harvesting chemical energy of glucose.
    What happens if oxygen is not present?
  • Lactic acid in muscle cells is sent via blood to liver, where it is converted back to pyruvic acid.
    Yeast are facultative anaerobes, can go either way. Will choose aerobic resp if oxygen is present; ferment only if anaerobic. Different fermentation reaction: produces ethanol and CO2. Hence, large tanks for fermentation of beer, wine, that keep out air (oxygen).
  • Hormones that affect appetite. (contrast that with hormones that affect digestive process, such as gastrin, secretin, CCK)
    Serotonin - causes decrease in appetite. Produced as result of exercise. Lack of exercise makes you hungry.
    Leptin - secreted by adipose tissue in response to high-fat foods. Suppresses appetite
    Ghrelin - apparently secreted by stomach cells, target is hypothalamus and stimulates appetite. Normally ghrelin levels rise before a meal, fall afterwards. Fasting causes increase in ghrelin levels.
    Body temp - rise causes loss of appetite
  • Factors that influence BMR
    Age – children and adolescents have a higher BMR
    thyroxine is the major control factor, More thyroxine means higher metabolic rate
    Gender, b/c males with higher % lean mass
    Body composition - % fat, as adipose tissue consumes very few calories.
    Age - usly increase in % fat
    Stress - increases BMR
    Food intake - starvation, fasting decreases BMR AND increases gain of weight after fasting stops. So “yo-yo” dieting makes it harder to lose each time.
    Genetics - unclear exactly how it works in humans. Obese strains in mice now studied.
    Total Metabolic Rate: Total amount of kilocalories the body must consume to fuel ongoing activities
    TMR increases with an increase in body activity
    TMR must equal calories consumed to maintain homeostasis and maintain a constant weight
  • Discuss accuracy and basis of the different methods.
    What does BMR do? Maintain body temp, run heart, lungs, digestion
    Surface area of body will affect how quickly you lose heat. Est surface area by height, wt.
  • BMR of metabolism

    1. 1. Metabolism of BMRMetabolism of BMR M.Prasad Naidu MSc Medical Biochemistry, Ph.D.Research Scholar
    2. 2. 1. Cellular respiration 2. Fermentation 3. Metabolism 4. BMR
    3. 3. Carbohydrate MetabolismCarbohydrate 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
    4. 4. Figure 14.18 Metabolic Pathways Involved inMetabolic Pathways Involved in Cellular RespirationCellular Respiration
    5. 5. Glycolysis harvests chemical energy byGlycolysis harvests chemical energy by oxidizing glucose to pyruvic acidoxidizing glucose to pyruvic acid Figure 6.9A Glucose Pyruvic acid Energy yield: 2 ATP and 2 NADH
    6. 6. Pyruvic acid is altered for the citricPyruvic acid is altered for the citric acid cycleacid cycle Figure 6.10 Pyruvic acid CO2 Acetyl CoA (acetyl coenzyme A)
    7. 7. The citric acid cycle completes the oxidationThe citric acid cycle completes the oxidation of organic fuelof organic fuel enzymes convert acetyl to CO2 and generate NADH and FADH2 molecules Figure 6.11A Acetyl CoA CITRIC ACID CYCLE 2 CO2
    8. 8. Steps in the Electron TransportSteps in the Electron Transport SystemSystem Figure 3.28 1. Set up H+ gradient using energy of e- from NADH, FADH2 2. Downhill flow of H+ is used to make ATP
    9. 9. cell inner membrane outer membrane mitochondrion
    10. 10. An overview of cellular respiration Figure 6.8 High-energy electrons carried by NADH GLYCOLYSIS Glucose Pyruvic acid CITRIC ACID CYCLE ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS Mitochondrion Cytoplasmic fluid
    11. 11. Fermentation is an anaerobic alternative toFermentation is an anaerobic alternative to aerobic respirationaerobic respiration  Without oxygen, cells can use glycolysis alone to produce small amounts of ATP ◦ But a cell must replenish NAD+ Glucose Pyruvic acid
    12. 12. In lactic acid fermentation, pyruvic acid is converted to lactic acid – NAD+ is recycled • Contributes to muscle soreness GLYCOLYSIS 2 Pyruvic acid 2 Lactic acidGlucose Figure 6.15B
    13. 13. Pathways of molecular breakdown Figure 6.16 Food, such as peanuts Polysaccharides Fats Proteins Sugars Glycerol Fatty acids Amino acids Amino groups Glucose G3P Pyruvic acid GLYCOLYSIS Acetyl CoA CITRIC ACIDS CYCLE ELECTRON TRANSPORT CHAIN AND CHEMIOSMOSIS
    14. 14. Biosynthesis of macromolecules from intermediates in cellular respiration Figure 6.17 ATP needed to drive biosynthesis PolyscaccharidesFatsProteins CITRIC ACID CYCLE Acetyl CoA Pyruvic acid G3P Glucose GLUCOSE SYNTHESIS Amino groups Amino acids Fatty acids Glycerol Sugars Cells, tissues, organisms
    15. 15. Body Energy BalanceBody 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
    16. 16. Regulation of Food IntakeRegulation 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
    17. 17. Metabolic Rate and Body Heat ProductionMetabolic 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
    18. 18. Estimation of BMREstimation 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)
    19. 19. ESTIMATION OF RESTING METABOLIC RATE (RMR) BASED ON FAT-FREE BODY MASS (FFM) FFM RMR FFM RMR FFM RMR (kg) (kcal) (kg) (kcal) (kg) (kcal) 30 1018 58 1623 86 2228 31 1040 59 1644 87 2249 32 1061 60 1666 88 2271 33 1083 61 1688 89 2299 34 1104 62 1709 90 2314 35 1126 63 1731 91 2336 36 1148 64 1752 92 2357 37 1169 65 1774 93 2379 38 1191 66 1796 94 2400 39 1212 67 1817 95 2422 40 1234 68 1839 96 2444 41 1256 69 1860 97 2465 42 1277 70 1882 98 2487 43 1299 71 1904 99 2508 44 1320 72 1925 100 2530 45 1342 73 1947 101 2552 46 1364 74 1968 102 2373 47 1385 75 1990 103 2595 48 1407 76 2012 104 2616 49 1428 77 2033 105 2638 50 1450 78 2055 106 2660 51 1472 79 2076 107 2681 52 1493 80 2098 106 2703 53 1515 81 2120 109 2724 54 1536 82 2141 110 2746 55 1558 83 2163 111 2768 56 1580 84 2184 112 2789 57 1601 85 2206 113 2811