Metabolism

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Metabolism

• The sum of all chemical reactions within the
  living cells

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• Anabolism
• Building new structures
• Requires energy
• Smaller molecules ? larger molecules

• Catabolism
• Breakdown of substances
• release of energy
• Larger molecule ? smaller molecules

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Nutrient Pool

• Source of substrates amino acids, lipids,
  sugars, vitamins, minerals

Stored in the liver, and delivered to all
tissues/cells via blood
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Cells produce energy in the mitochondria
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Adenosine Triphosphate ATP
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Carbohydrate Metabolism

• Glycolysis breaking sugar into pyruvic acid
  occurs in cytoplasm of cell. O2 nondependent
• TCA or Krebs Cycle O2 dependant. Occurs in
  mitochondria
• Electron transport system respiratory chain
  occurs in mitochondria
• Anaerobic metabolism ? lactate production

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Activation Energy

• Need to spend energy to make energy
• To begin the process of Glycolysis the cell
  uses 2 ATP. The process of glycolysis yields 4
  ATP net gain 2 ATP
• 4 ATP from phosphorylation
• -2 ATP activation energy
• 2 ATP net gain to cell

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Glycolysis the Lysis or breaking apart of
glucose occurs in the cytoplasm of all cells.
This process does not require oxygen. It is
therefore referred to as an anaerobic process.
The net yield of energy in glycolysis is 2 ATPs
2 NADH
NADH Nicotinamide adenine dinucleotide
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The production of lactate is a common fate of
pyruvate in skeletal muscles, which have been
working very hard and have used up all their
oxygen but are still producing pyruvate. As the
lactate (lactic acid) builds up in the muscles
they will feel sore
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Intermediate Step

• The First Step in the Krebs Cycle is to convert
  pyruvate into a two-carbon fragment, then attach
  it to another coenzyme known as coenzyme A or
  CO-A. The enzyme that accomplishes thus is a
  large enzyme known as the pryruvate
  dehydrogeneses complex
• Gives off 1 NADH for each acetyl CoA produced 2
  NADH total/glucose

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Krebs Cycle

• Cycle goes thru a revolution for each Acetyl CoA
  that enters 2 Acetyl CoA are formed from each
  glucose molecule
• Will give off ATP, NADH FADH as well as CO2

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Energy Yield of TCA Cycle

• 1 ATP produced by each turn of cycle
• Each turn of cycle also produces 3 NADH
• 1 FADH2 FADH2 flavin adenine
  dinucleotide
• NADH and FADH2 will then go into the electron
  transport system to yield ATP
• 2 turns of cycle are completed for each glucose
  molecule
• 2 ATP 6 NADH 2 FADH2

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Electron Transport System

• Imbedded in the inner mitochondria membrane are a
  series of electron carriers. These electron
  carriers pass electrons from NADH and FADH to one
  another down a red-ox stairway. The net result of
  this series of step-wise electron exchanges is to
  pump H (protons) out of the matrix into the
  outer compartment between the outer and inner
  membrane of the mitochondria.

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Energy Generated in ETS

• NADH 2 from intermediate step 6 from TCA cycle
  8 NADH each NADH will yield 3 ATP The 2
  NADH from glycolysis is said to only yield 4 ATP
  in the ETS
• FADH2 2 from TCA cycle each FADH2 will yield
  2 ATP
• Total ATP generated in ETS 24 4 28 4 ATP
  32 ATP 4 ATP 36 total ATP

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Metabolic Rate

• Total amount of energy produced and used by the
  body per unit of time
• Daily input of energy should be equivalent to the
  metabolic expenditure
• If too low will cause weight loss
• negative energy balance
• If too high will cause weight gain
• positive energy balance

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Metabolic Energy Use

• Basal Metabolic Energy BMR energy needed to
  maintain resting body functions
• Thermic Effect of Food TEF energy needed to
  digest and ingest nutrients accounts for 10
  of daily energy needs
• Muscular Activity energy needed to perform all
  functions above BMR accounts for 30 of daily
  energy needs

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Basal Metabolic Rate

• Roughly 1 kcal/kgBW/hr for men and 0.9
  kcal/kgBW/hr for women
• Example 130 lb woman
• Convert lb to kg 130 / 2.2 59 kg
• 2. Multiply 59 kg x 0.9 kcal/hr x 24 hrs 1274
  kcals/day
• Example 170 lb man 170/2.2 77.2 kg
• 77.2 kg x 1.0 kcal/hr x 24 hrs 1852.8 kcals/day

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Basal Metabolic Rate of selected Organs

• When at rest, the percent of total body energy
  that is used by various organs
• LIVER 27
• BRAIN 19
• SKELETAL MUSCLE 18
• KIDNEYS 10
• HEART 7