Respiration

• Respiration

  Release of energy from food within cells
• External respiration

  Process by which organisms exchange gases with their environment
• Internal respiration

  Controlled release of energy (ATP) from food, which is controlled by enzymes. The food involved is usually glucose. Can be aerobic (mitochondria) or anaerobic
• Aerobic respiration

  Controlled release of energy (ATP) from food using oxygen
• ATP stands for adenosine triphosphate and is composed of

  • Adenine
  • Phosphate
  • Ribose
• Why should I care about ATP

  • Reusable
  • Highly energised
• Aerobic respiration role

  To make energy in the form of ATP and maintain body temperature of 37 °C
• Where does aerobic respiration occur

  Mitochondria
• Aerobic respiration

  ATP is broken down into ADP + P to supply energy for metabolic reactions e.g muscle contraction
• Aerobic respiration

  • Glucose is broken down to produce energy, CO2 and H2O (efficient)
  • CO2 and H2O are waste products and are released into the atmosphere
• Experiment) 1. What test is used to test for the presence of alcohol, 2. State the chemicals, 3. State the colour change if alcohol is present and what is produced

  1. Iodoform test
  2. Potassium iodide and sodium hyperchlorite
  3. Brown → yellow (crystals)
• Aerobic respiration equation

  C6H12O6 + 6O2 → 6CO2 + 6H2O +energy (ATP)
• Stage 1 aerobic respiration

  Glycolysis
• Stage 2 aerobic respiration

  Krebs cycle and electron transport chain
• Glycolysis (stage 1 aerobic respiration) takes place in the

  Cytoplasm as enzymes are found here which can speed up the process
• Glycolysis produces a small amount of ATP and it's therefore an inefficient energy releasing system
• Glycolysis

  • 6 carbon carbohydrate -C6 (glucose) is converted to two 3 carbon molecules -C3 called pyruvate along with a small amount of energy
  • This energy is used to form 2 ATP molecules and NADH
  • 75% of the energy in the glucose molecule remains stored in the bonds of the pyruvic acid as the glucose is only partially broken down
• Carbons

  • C6→ glucose
  • C3→ pyruvate
  • C2→ acetyl co enzyme A
• Adenosine triphosphate components

  1. Adenine
  2. Phosphate
  3. Ribose
• What does NAD stand for (NADH)

  1. N→ nicotinamide
  2. A→ adenine
  3. D→ dinucleotide
• Stage 1 of aerobic respiration (glycolysis) does not use oxygen but can take place in the presence of it
• Stage 2 aerobic respiration

  • Krebs cycle occurs in the matrix of the mitochondria and the electric transport chain occurs in the cristae of the mitochondria
  • This stage uses oxygen
  • Pyruvate (C 3 ) enters the mitochondria if oxygen is present
  • Pyruvate is converted to an acetyl group by the removal of CO2 (fate: atmosphere) and protons (H+)
  • Co - enzyme A links to the acetyl group, forming acetyl co - enzyme A
  • The energy that was in the acetyl co-A is released in a number of steps through the Krebs cycle in the form of high energy electrons (e-)
  • The electrons along with the protons combine with the electron acceptor NAD+ to form NADH, which enters into the electron transport system
  • During this cycle acetyl co A release CO², ATP, NADH and H+
  • As ATP is produced phosphorylation occurs and a single ADP is converted to ATP and water
• Products of the Krebs cycle and their fate

  • CO2 → atmosphere
  • ATP → provides energy for the cell
  • NADH → Releases electrons and protons at the electron transport chain
• Electron transport chain (ETC) (takes place in the cristae of mitochondria)

  • NADH enters (with the boyz)
  • Oxygen is necessary
  • High energised electrons are passed from NADH to the first of these molecules. These electrons are produced when NADH is broken down to NAD+ and H+ and e-
  • The electrons are used to start off the process of producing ATP
  • As electrons pass from molecule to molecule they lose some of their energy
  • Some of this energy is used to form ATP , the rest is lost as heat
  • At the end of each system the low energy electron is removed by combining it with oxygen and hydrogen to form water
  • The production of ATP by the ETS is called oxidative phosphorylation as it requires oxygen and phosphate
• Electron transport chain background info that couldn't fit into other card

  • The foldings of the cristae increase the number of electron transport systems (ETS) that can fit into them
  • Each ETS consists of a number of molecules mainly proteins
  • The main significance of the ETS is that it produces energy rich ATP
  • Oxygen is essential as it accepts the low energy electron at the end of the chain
  • If oxygen is absent aerobic organisms may die as there is no oxygen to accept the low energy electron and no ATP may be formed
  • Chemicals such as cyanide may be fatal because they prevent some of the proteins from receiving and passing on electrons meaning ATP cannot be produced
• Anaerobic respiration

  Controlled release of energy (ATP) from food without the use of oxygen
• Anaerobic respiration

  • Can occur in the presence of oxygen but doesn't use it
  • Occurs in cytosol
  • Less efficient than aerobic respiration as there is a small energy release
  • Glycolysis occurs, releasing a small amount of energy: ATP and 2 molecules of NADH are produced in the process
  • In absence of oxygen the pyruvate is converted to lactic acid (animal/muscle cells) or carbon dioxide and ethanol (yeast)
  • In each case the 2 NADH break down into 2 electrons and 2 protons which combine with the pyruvate to form lactic acid/CO2 + ethanol