intro to ATP and metabolism

INTRO TO ENERGY, LIFE, AND METABOLISM

Metabolism is the sum of all chemical reactions in the human boyd

  • your body requires thousands of chemical reactions to defend, develop, grow, renew, repair, reproduce, and respond to environmental factors 

  • the dazzling array of metabolic reactions occur in-

    • blood

    • cells (cell membrane, cytosol, organelles, organelles membranes)

    • cerebrospinal fluid

    • digestive, respiratory, urogenital tracts

    • extracellural matrix

    • lymph fluid

    • tissue (interstitial) fluid 

two types of metabolic reactions 

  1. Anabolic (biosynthetic): endergonic (require energy)

    1. DNA replication, messages RNA processing, transcription, translation

    2. small molecules are assembled into large ones. Energy is required

  2. catabolic: are exergonic (release energy) 

    1. release energy from food molecules to make ATP and GTP that energize anabolism 

    2. glycolysis, Krebs cycle, pyruvate oxidation 

    3. large molecules are broken down into small ones, energy is released. 

All eukaryotes and prokaryotes require energy to develop, grow, maintain, repair, reproduce, and respond 

  • herbivores, carnivores, omnivores 

autotrophs are self-feeding because they produce carbohydrates from carbon dioxide (CO2) 

  • Photosynthetic Autotrophs Use Sunlight To Make ATP And NADPH

    •  ATP And NADPH Energize The Enzymes That Convert CO2 To Carbohydrate

    • Photosynthetically Active Radiation (PAR), Also Called Visible Light, Is The Type Of Sunlight That Energizes Photosynthes 

some autotrophs use chemosynthesis to convert CO2 molecules into carbohydrates 

  • they use inorganic chemicals (H2, H2S) to make atp and NADH that energize the enzymes that convert CO2 to carbohydrate 

    • inorganic chemicals do not contain bonds between carbon and hydrogen atoms 

heterotrophs (feed on others) cannot perform chemosynthesis or photosynthesis 

  • they eat autotrophs and other heterotrophs to obtain food 

    • they require an external source of food molecules like carbs, lipids, nucleic acids, and proteins 

cells require external energy to make the energy-rich ATP and GTP molecules that sustain life

  • these energy sources include food, inorganic chemicals like H2S, and sunlight

all cells use adenosine triphosphate (ATP) to fuel endergonic (energy-requiring) reactions 

  • food molecules supply the energy to make ATP 

  • the phosphate (PO4) to PO4 bond store energy 

  • ATP is also- 

    • A signaling molecules 

    • the A in RNA 

All cells use the energy-rich guanosine triphosphate (GTP) molecule to fuel some endergonic reactions 

  • food molecules supply the energy to make GTP

    • the phosphate (PO4) to PO4 bond in GTP stores energy 

  • GTP is the G in RNA

  • nucleoside-diphosphate kinases (NDK) converts GTP to ATP 

cells use ATPase enzymes to release and capture the energy stored in ATP 

  • ATPases link the released energy to endergonic reactions 

ATPases require magnesium (Mg++) as a cofactor 

  • MG++ ions are cofactors for ~300 cellular reactions 

    • Many enzymes need a cofactor (vitamin or mineral) to activate them. Without the cofactor, the enzyme can’t lock the reacting substance (substrate) into its active site, so the reaction can’t take place. Most vitamin deficiency diseases happen this way. 

Cells require a continuous supply of ATP molecules to satisfy their significant energy demands 

  • human cells consume > billion ATP molecules/second

    • each ATP molecule is consumed and resynthesized ~10000X daily (every 8.64 seconds) 

the total mall of ATP your body synthesizes daily is equivalent to your body mass (~50-100KG) 

  • the body contains ~50-250g of ATP at any point in time. 

The circulatory system continuously delivers the raw materials (O2 and glucose) your cell needs to make ATP 

  • your cells must constantly synthesize ATP to satisfy their energy demands. 

Eukaryotic cells synthesize ATP in 3 locations 

  • cytosol (glycolysis) 

  • mitochondrion (cellular respiration requires O2) 

  • nucleus (NUDIX5 enzyme converts ADP-Ribose to ATP) 

all cells must couple reach endergonic reaction to an exergonic reaction that releases energy

  • ATP hydrolysis is coupled to glutamine synthesis 

    • ATP hydrolysis releases more energy than is required to synthesize glutamine 

      • the surplus energy helps maintain core body Temperature 

the medical consequences of inefficient ATP synthesis 

  • pellagra (3Ds) is a nutritional disorder due to insufficient dietary niacin (Vitamin B3) intake that reduces ATP synthesis 

    • Niacin (B3) is a substrate for nicotinamide adenine dinucleotide (NAD+) synthesis