CELLULAR RESPIRATION
  • Adenosine diphosphate : A compound with two phosphate bonds, the second bond being rich forms ATP by addition of inorganic phosphate.
  • Adenosine triphosphate : A nucleotide containing energy for many biochemical processes by undergoing enzymatic hydrolysis.
  • Aerobic respiration : Occurs in mitochondria; require molecular oxygen; process can be divided into two mutually dependent steps – Krebs cycle also called as TCA cycle and Electron transport system (ETS).
  • Aerobic respiration : Respiration occurring in the presence of oxygen.
  • Anaerobic glycolysis : Degradation of glucose into lactic acid in the absence of oxygen yielding two ATP molecules.
  • Anaerobic respiration : It is carried out in the absence of oxygen.
  • Anaerobic respiration : Occurs in cytoplasm, molecular oxygen is not needed; electrons removed from substances are transferred by oxidoreductases to electron acceptors other than oxygen; its end products are lactic acid or ethanol.
  • Cellular respiration : Exchange of gases between the cell and its surrounding, as also between the organisms and its environments. It involves diffusion of oxygen into the cell, its utilization to oxidize glucose, production of carbon dioxide and its diffusion out of the cell – aerobic or anaerobic.
  • Electrochemical gradient : The sum of gradients of mass and electric charge for an ion across a membrane.
  • Electron acceptor : A substance active to receive electrons in oxidation and reduction reactions.
  • Electron transport : Movements of electrons from substrate to oxygen through a respiratory chain.
  • Electron Transport System (ETS) : Series of biochemical steps by which energy is transferred from a higher to a lower, each step involves a specific electron carrier that has a particular energy level with the carriers organized in a sequence of decreasing energy; this assembly of electron transport enzymes is also called mitochondrial respiratory chain (MRC) and is vital in both photosynthesis and aerobic cellular respiration.
  • Fermentation : Another kind of respiration occurs in which glucose is broken down into simple compounds, by enzymes, in the complete absence of molecular oxygen.
  • Glycolysis : Anaerobic process of breaking down of glucose into pyruvic acid that occurs in the cytoplasm.
  • Glycolysis : First stage of cellular respiration, with or without oxygen.
  • Krebs (TCA) cycle : Tricarboxylic acid cycle; a circular series of reactions that take place in matrix of mitochondria forming part of aerobic cell respiration. The steps of the cycle were demonstrated by Nobel Laureate Sir Hans Krebs (1900-81).
  • NAD : Nicotinamide adenine dinucleotide, a coenzyme that readily accepts or gives up hydrogen. It acts as an energy carrier in the cell.
  • NADP : Nicotinamide adenine dinucleotide phosphate. It is a coenzyme that readily accepts hydrogen from an electron transport system in photo-phosphorylation passing the electron on to the calvin cycle of photosynthesis.
  • Oxidative phosphorylation : Coupling of phosphate with ADP to form ATP using the energy provided by electron transfer.
  • Proton gradient : The difference in proton concentration across the inner membrane of mitochondria is called Proton gradient.