Energy Systems

• Absolute Differences is more general values, Relative is more specific values
• Fatty acids, stored as triglycerides in muscle/adipocytes

  Amino acids use carbon skeleton to create energy
• ATPase breaks down ATP using water (hydrolysis), to ADP + phosphate + H+
• Rate limiting enzymes (negative feedback)
• Aerobic occurs in mitochondria, anaerobic occurs in cytosol
• Phosphofructokinase (PFK):

  Produces fructose 1,6-biphosphate
• Hexokinase:

  Produces Glucose-6-phosphate
• 1. ATP-PCr system
  2. We use it to rebuild ATP, not for direct cellular work
• Creatine Kinase moves reaction in ATP-PCr system along by phosphorylating ADP to ATP
• • First 2 seconds, ATP is used, and ADP is available
  • With ADP available, creatine kinase is activated and ATP stabilizes
  • However, in the end 10-15 seconds, the ATP-PCr system crashes and glycolysis starts
  • Then ATP-PCr takes 2-3 minutes to fully replenish our stores
• Sit to stand, skeletal muscle dilates, and glucose needs to go into cells

  Transport proteins need to uptake protein

  Insulin needs to be available to uptake glucose

  Exercise-mediated Glut 4, this is important for diabetics

  When calcium is released from the sarcoplasmic reticulum it can stimulate GLUT 4
• Lactate

  • It buffers hydrogen atoms, which lessens the acidity
  • It is a placeholder, and the lactate shuttle helps us convert lactate back to pyruvate
  • Distance runners are much better at using lactate (more MCT 1 stores)
• Cori cycle (lactic acid to glucose) reverse glycolysis (gluconeogenesis)
• Pyruvate processing occurs in mitochondrial matrix

  Krebs cycle occurs in the mitochondrial matrix

  The ETC occurs in the INNER mitochondrial membrane
• Slow glycolysis continues to be metabolized

  Taking pyruvate and continuing through Krebs cycle and ETC
• Glycolysis to KREBS

  • Pyruvate dehydrogenase is responsible for taking one carbon away from pyruvate. Results in a 2-carbon unit (Acetate) and CO2
  • Acetate then combines with CoA to form Acetyl CoA
• Need to know Pyruvate → P dehydrogenase → NADH, CO2 formed →aceytl-CoA→carbons chopped off creating NADH + FADH
• In the Krebs Cycle: 6 NADH produced, 8 total, including glycolysis
• 1 NADH = 3 ATP, 1 FADH = 2 ATP
• NADH comes in earlier, and FADH starts at complex 2, thus is why NADH produces more ATP on average.
• • Creatine Kinase - ATP-PCr 
  • Glycolysis - PFK
  • Krebs - Isocitrate dehydrogenase
  • ETC - Cytochrome Oxidase
• Our ATP production is dependent on the amount of carbons, so that is why lipids>carbs
• The objective of lipid metabolism The objective is to remove glycerol head through hormone-sensitive lipase and lipoprotein lipase
• 1. Have to break it down
  2. Have to transport it through blood and using carnitine shuttle
  3. Have to have more oxygen available
  4. Beta oxidation then needs to occur
  5. Fatty acid is broken down to produce acetyl coA
  6. FADH and NADH produced
  7. Cleave a carbon every two carbons
• Do not metabolize lipids in the cytosol
• Beta-oxidation

  • Occurs in mitochondrial matrix
  • Slowest ATP production
  • Produces Acetyl CoA, 1 NADH, 1 FADH
  • Uses fatty acid chain
  • Endless capacity
  • Need O2
  • Requires Carnitine shuttle to get into matrix
  • Higher aerobic can rely more on this system
  • Substrate are lipids
• • Cross Over Concept
  • Showing a graph of substrate utilization on exercise intensity
  • Under 65%, we use lipids, over we use carbs