BMS 100 - Chapter 4 Outline
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Cellular Respiration – Figure 8.11
  1. Glycolysis
    • = first phase of glucose breakdown
    • one glucose molecule (6C) -> two pyruvic acid molecules (3C each)
    • some of the energy in glucose is transferred to ATP molecules
    • does not require oxygen or produce carbon dioxide
  2. Aerobic respiration (requires oxygen)
    • = second phase of glucose breakdown
    • pyruvic acid is channeled into Krebs cycle (citric acid cycle) in mitochondria
    • final products are carbon dioxide, water, and energy (ATP and heat)
    • yields much more ATP than does glycolysis alone
Metabolism in Muscle Fibers
see “Oxygen Supply and Cellular Respiration,” p. 176-177
  1. During rest or moderate exercise, muscles receive enough oxygen (from blood) to support aerobic respiration.
  2. During strenuous exercise, muscles may consume oxygen faster than it can be supplied. Under these conditions, some muscles may switch to anaerobic respiration.
  3. Anaerobic respiration
    • Under anaerobic conditions: pyruvic acid -> lactic acid
    • Lactic acid cannot be metabolized until oxygen becomes available again.
    • May cause muscle fatigue due to depletion of fuel, accumulation of waste, and other factors.

  4. Comparison of Aerobic and Anaerobic Respiration (fill in the blanks)
    Requires oxygen? . .
    What is the waste product? . .
    How is the waste processed? . .
    Advantages/Disadvantages? . .

  5. “Fast Twitch” and “Slow Twitch” Muscle
    1. Size: which are larger and stronger?
    2. Color: which contain more myoglobin (deep red) for oxygen storage?
    3. Slow twitch fibers use primarily ______________ respiration.
    4. Fast twitch fibers use primarily ______________ respiration.
    5. Which provide greater endurance and why?
    6. Which fatigue more easily?
    Metabolic Reactions (pp. 75-80)
  1. Metabolism = all chemical reactions in the body (from Greek “metaballein”: to change).
  2. Enzymes control metabolism, which consists of many separate "metabolic pathways." (Fig. 4.8).
  3. Anabolism and Catabolism
    1. Anabolism "builds up" large molecules from smaller molecules.
      • generally includes pathways leading away from the citric acid (Krebs) cycle
      • When does anabolism prevail over catabolism?
      • What is likely to happen to body weight when anabolic processes prevail?
      • Examples of anabolic processes:
        1. monosaccharides -> glycogen OR fatty acids
        2. glycerol + fatty acids -> triglycerides (fats)
        3. amino acids -> proteins (surplus amino acids are converted to glucose or fatty acids)
    2. Catabolism "breaks down" larger molecules into smaller ones.
      • generally includes pathways leading toward the citric acid (Krebs) cycle
      • When does catabolism prevail over anabolism?
      • What is likely to happen to body weight when catabolic processes prevail?
      • Examples of catabolic processes:
        1. glycogen -> glucose
        2. triglycerides -> glycerol and fatty acids
          • Fatty acids may be used for energy by the heart, liver & muscles -- main source of energy for prolonged exercise.
        3. proteins -> amino acids (may be converted to glucose or may enter the citric acid cycle to provide ATP)
Chapter 4 Questions at OLC – 1, 2, 5, 6, 7, 8, 9, 10, 12, 26, 29, 30, 31, 32, 33, 34, 35, 36
Spring 2011