aerobic respiration

Examples of aerobic respiration in the following topics:

• Energy Requirements

  • Cardiac cells contain numerous mitochondria, which enable continuous aerobic respiration and production of ATP for cardiac function.
  • Cardiomyocytes contain large numbers of mitochondria, the power house of the cell, enabling continuous aerobic respiration and production of ATP, which is required for mechanical muscle contraction.
  • Aerobic metabolism is a necessary component to support the metabolic function of the heart.
  • Myoglobin transfers oxygen from the blood to the muscle cell and also stores reserve oxygen for aerobic metabolic function in the muscle cell.
  • While aerobic respiration supports the normal activity of the heart, aerobic respiration may also provide additional energy during brief periods of oxygen deprivation.

• The Energy Cycle

  • Finally, in the process of breaking down food, called cellular respiration, heterotrophs release needed energy and produce "waste" in the form of CO2 gas.
  • Photosynthesis absorbs light energy to build carbohydrates in chloroplasts, and aerobic cellular respiration releases energy by using oxygen to metabolize carbohydrates in the cytoplasm and mitochondria.
  • Aerobic respiration consumes oxygen and produces carbon dioxide.
  • These two powerhouse processes, photosynthesis and cellular respiration, function in biological, cyclical harmony to allow organisms to access life-sustaining energy that originates millions of miles away in the sun.
  • Aerobic respiration consumes oxygen and produces carbon dioxide.

• Transforming Chemical Energy

  • Cellular respiration is the process of transforming chemical energy into forms usable by the cell or organism.
  • When oxygen is used to help drive the oxidation of nutrients the process is called aerobic respiration.
  • Aerobic respiration is common among the eukaryotes, including humans, and takes place mostly within the mitochondria.
  • Respiration occurs within the cytoplasm of prokaryotes.
  • The energy released during cellular respiration is then used in other biological processes.

• Slow-Twitch and Fast-Twitch Muscle Fibers

  • The ATP required for slow-twitch fibre contraction is generated through aerobic respiration (glycolysis and Krebs cycle) whereby 30 molecules of ATP are produced from each one of glucose in the presence of oxygen.
  • The reaction is slower than anaerobic respiration, which is why it is not suited to rapid movements, but much more efficient which is why slow-twitch muscles do not tire quickly.
  • Unlike slow-twitch fibers fast twitch-fibers rely on anaerobic respiration (glycolysis alone) to produce two molecules of ATP per molecule of glucose.
  • Whilst much less efficient than aerobic respiration it is not rate limited by a requirement for oxygen making it ideal for rapid bursts of movement.
  • A by-product of anaerobic respiration is lactate (lactic acid) which accumulates in the muscle tissue reducing the pH (making it more acidic, and producing the stinging feeling in muscles when exercising) which inhibits further anaerobic respiration.

• Oxygen

  • An aerobic organism or aerobe is an organism that can survive and grow in an oxygenated environment.
  • Several varietis of aerobes exist .
  • Obligate aerobes require oxygen for aerobic cellular respiration.
  • In a process known as cellular respiration, these organisms use oxygen to oxidize substrates (for example sugars and fats) in order to obtain energy.
  • Aerobically different bacteria behave differently when grown in liquid culture: 1) Obligate aerobic bacteria gather at the top of the test tube in order to absorb maximal amount of oxygen. 2) Obligate anaerobic bacteria gather at the bottom to avoid oxygen. 3) Facultative bacteria gather mostly at the top, since aerobic respiration is advantageous (ie, energetically favorable); but as lack of oxygen does not hurt them, they can be found all along the test tube. 4) Microaerophiles gather at the upper part of the test tube but not at the top.

• Anaerobic Cellular Respiration

  • However, many organisms have developed strategies to carry out metabolism without oxygen, or can switch from aerobic to anaerobic cell respiration when oxygen is scarce.
  • Certain prokaryotes, including some species of bacteria and archaea, use anaerobic respiration.
  • Eukaryotes can also undergo anaerobic respiration.
  • This type of fermentation is used routinely in mammalian red blood cells and in skeletal muscle that has an insufficient oxygen supply to allow aerobic respiration to continue (that is, in muscles used to the point of fatigue).
  • This means that they can switch between aerobic respiration and fermentation, depending on the availability of oxygen.

• Internal Respiration

  • Internal respiration refers to two distinct processes.
  • The oxygen supply for cellular respiration comes from the external respiration of the respiratory system.
  • The net formula for cellular respiration is:
  • Cellular respiration can occur anaerobically without oxygen, such as through lactic acid fermentation.
  • This process however is very inefficient compared to aerobic respiration, as without oxidative phosphorylation, the cell cannot produce nearly as much ATP (2 ATP compared to 38 during cellular respiration).

• Aerobic Training vs. Strength Training

  • Aerobic activity relies on the availability of oxygen for energy production, whereas anaerobic activity utilizes primarily glycolysis.
  • These slow twitch fibers generate energy for ATP re-synthesis by means of a long-term system of aerobic energy transfer.
  • Aerobic respiration, typical of long-distance running and other forms of exercise involving endurance, uses predominantly Type I fibers, which resist fatigue for long periods of time .
  • A number of studies have examined the health benefits of aerobic and/or strength training in improving health and treating health issues.
  • Running a marathon is emblematic of extended aerobic exercise that employs Type I (slow-twitch) muscles for extended endurance, and prioritizes aerobic metabolic pathways.

• Respiration and Proton Motive Force

  • Respiration is one of the key ways a cell gains useful energy to fuel cellular activity.
  • Chemically, cellular respiration is considered an exothermic redox reaction.
  • Aerobic reactions require oxygen for ATP generation.
  • During aerobic conditions, the pyruvate enters the mitochondrion to be fully oxidized by the Krebs cycle.
  • Aerobic metabolism is up to 15 times more efficient than anaerobic metabolism, which yields two molecules ATP per one molecule glucose.

• Electron Donors and Acceptors in Anaerobic Respiration

  • Anaerobic respiration is the formation of ATP without oxygen.
  • These molecules have a lower reduction potential than oxygen; thus, less energy is formed per molecule of glucose in anaerobic versus aerobic conditions.
  • Many different types of electron acceptors may be used for anaerobic respiration.
  • Organic compounds may also be used as electron acceptors in anaerobic respiration.
  • A molecule other than oxygen is used as the terminal electron acceptor in anaerobic respiration.