biology respiration

• Respiration


  The internal chemical reaction which releases energy to be used within the body
• Understanding of respiration


  • Vital to many scientists and healthcare professionals
  • Biochemists can analyse the rates of cellular respiration in samples of tissues
  • Sport physiologists can determine whether an individual is respiring aerobically or anaerobically using non-invasive methods
  • Engineers use their understanding of cellular respiration to clean up contamination in the environment, using cells which convert contaminants into energy
• Breathing


  The physical external process that brings air with a high percentage of oxygen into the body and exchanges it for carbon dioxide
• Breathing is not the same as respiration
• Methods to monitor the respiratory system


  • Breathing rate
  • Spirometer (to measure vital capacity, tidal volume, breathing rate, oxygen uptake)
  • Oxygen uptake
• Using a spirometer


  1. Person breathes in and out through the spirometer

  2. Carbon dioxide is absorbed from the exhaled air

  3. Trace is drawn on rotating drum or digital graph is formed
• Spirometer data


  Can be used to calculate vital capacity, tidal volume, breathing rate, oxygen uptake
• A small amount of air, known as the residual volume, is always retained in the lungs
• Cellular respiration


  The process of breaking down materials from digestion (mainly glucose) over a series of steps to form ATP
• Phosphorylation


  The addition of a phosphate group to ADP to form ATP
• Stages of cellular respiration

  1. Glycolysis (in cytoplasm)

  2. Krebs cycle (in mitochondria)

  3. Electron transfer chain (in mitochondria)
• Glycolysis


  • Converts glucose into pyruvate
  • Produces 2 ATP
  • Produces 2 NADH
• Substrate-linked phosphorylation


  When a cell produces enough energy to convert ADP to ATP without involving the electron transfer chain
• Krebs cycle


  • Series of reduction and oxidation reactions that release hydrogen
  • Produces 1 ATP per turn
  • Releases carbon dioxide
• Electron transfer chain


  • Electrons passed along a series of carriers in the inner mitochondrial membrane
  • Final electron acceptor is oxygen, forming water
  • Releases energy used to phosphorylate ADP to ATP (oxidative phosphorylation)
• Anaerobic respiration


  • Occurs when oxygen is unavailable or in short supply, only glycolysis pathway continues
  • In animals, pyruvate converted to lactic acid
  • In plants, pyruvate converted to ethanol and carbon dioxide
  • No ATP formed in fermentation stage
• Basal metabolic rate (BMR)


  • The rate the body uses energy at rest, for basic bodily functions
  • Measured in kcal/day or kJ/day
  • Varies based on gender, age, activity level, obesity level
  • Can be measured by direct calorimetry (heat production) or indirect calorimetry (CO2 production, O2 use)