Cellular Respiration

• Cellular respiration

  The process by which food energy (glucose) is broken down to form usable energy called ATP in which cells need
• Adenosine triphosphate (ATP)

  Adenine with three phosphates with ribose as its sugar, a nucleic acid
• Cellular respiration occurs in the mitochondria
• Cellular respiration

  C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O
• C6H12O6

  Glucose
• 6 O2

  Oxygen
• 6 CO2

  Carbon dioxide
• 6 H2O

  Water
• Aerobic respiration


  This type of respiration requires oxygen
• Aerobic respiration

  C6H12O6 + 6 O2 -> 6 CO2 + 6 H2O + ATP
• Reactants (inputs)

  C6H12O6 + 6 O2
• Products (outputs)

  6 CO2 + 6 H2O + ATP
• Aerobic respiration

  • The most efficient way for cells to produce energy
• Glycolysis

  Takes place in the cytoplasm (cytosol of the cytoplasm), anaerobic (does not require oxygen), glucose is converted into a more usable form called pyruvate, takes a little ATP itself to start up, Net Yield: approximately 2 pyruvate, 2 ATP molecules, and 2 NADH
• Intermediate step

  Pyruvate is transported into the mitochondria (mitochondrial matrix) where it will be oxidized and converted to acetyl CoA, carbon dioxide is released and 2 NADH are produced
• Krebs Cycle (Citric Acid Cycle)

  An aerobic process, with 2Coa, carbon dioxide is released and 2 ATP, 6 NADH, AND 2 FADH2 are produced
• Electron Transport Chain and Chemiosmosis

  Inside the inner mitochondrial membrane, an aerobic step, electrons from the NADH and FADH2 are transferred to protein complexes and electron carriers, the electrons are used to generate a proton gradient as protons are pumped across to the intermembrane space, the protons can travel through ATP synthase to make ATP
• Oxygen is the final acceptor of the electrons and when it combines with two hydrogens, H2O (water) is formed
• Around 30-38 net ATP molecules are formed per glucose molecule
• Anaerobic respiration

  Also called fermentation, this type of respiration does not require oxygen (ex. for bacteria, archaea, yeast, and muscle cells), produces less energy than aerobic respiration, but it's still important for some cells to survive in low-oxygen environments
• Anaerobic respiration

  An organism can go through anaerobic respiration that has the same cycle as aerobic respiration except that other molecules are used the as the last electron acceptor (ex. sulfate), other organisms, instead, only go through glycolysis as it doesn't require oxygen in the process called fermentation
• Fermentation

  A way to be able to handle having no oxygen, allows glycolysis to happen and for it to keep happening, adds another step to the end of glycolysis to help regenerate NAD+
• Alcoholic fermentation

  As done by some types of yeast, its first glycolysis yields 2 net ATP, 2 pyruvate, and 2 NADH, the 2 pyruvate is then used to produce carbon dioxide and 2 ethanol (alcohol; a waste product which is why yeast is used to make alcoholic products and in baking bread as alcohol escapes for it to rise), the derivative of pyruvate, acetaldehyde, can act as an electron acceptor so the 2 NADH can be oxidized to 2 NAD+ for glycolysis to start all over
• Lactic acid fermentation

  As done by muscle cells (shifts to this when in depth of oxygen), starts with glycolysis that yields 2 net ATP, 2 pyruvate, and 2 NADH, the 2 pyruvate will yield 2 lactate and the pyruvate can act as the electron acceptor, allowing NADH to be oxidized into 2 NAD+ so that glycolysis can start again, also done by bacteria that are involved in making yogurt (lactate/lactic acid contributes to its sour taste)