Download Respiration Eq. for reaction: C6H12O6 + 6O2 ------

Respiration
Energy is needed by organisms for the following:
1) synthesis of complex substances from simpler substances
2) active transport of substances against concentration gradients
3) mechanical work (muscle contractions, cell division and movement, growth)
4) bioluminescence and electrical discharge, nerve impulse transmission
5) maintain body temperature
Respiration is the process by which organisms derive energy in the form of ATP from
chemical energy (a.k.a. food) which may be used for the organism’s metabolism and
growth.
enzymes
Eq. for reaction: C6H12O6 + 6O2 -------> 6CO2 + 6H2O + ATP
- occurs in the cytoplasm and then the cristae and matrix of the mitochondria
- reaction is an oxidation reaction (uses oxygen): aerobic respiration
- energy is in the form of ATP (adenosine tri-phosphate)
- some is lost as heat (responsible for organism’s body temperature)
- produces 38 ATP (2 from Glycolysis, 2 from Krebs cycle and 34 from Oxidative
Phosphorylation) = 2870 kJ energy
- energy comes from breaking the chemical bonds in glucose
Glucose (C6H12O6): simple sugar which is split in first stage of respiration: Glycolysis
- may be derived from photosynthesis and stored starch in plants
- may be derived from fats and glycogen in animals
Oxygen (O2): product of photosynthesis that is required to oxidize glucose in respiration
Carbon dioxide (CO2): waste product from the Krebs cycle stage of respiration
Water (H2O): produced at the end of the electron transport chain in oxidative
phosphorylation, where O2 is an e- and H+ acceptor.
May also occur without oxygen… known as anaerobic respiration
- does not produce as much energy as aerobic respiration (only 2 ATP)
Alcoholic fermentation: Glucose  ethanol + CO2 + energy (e.g. yeast, a unicellular
fungus)
Lactate Pathway: Glucose  lactic acid + energy (e.g. occurs in muscle cells when
oxygen has been used up in heavy exercise and oxygen cannot be replenished fast enough
(oxygen debt). Lactic acid must be broken down after exercise ceases, which is why one
continues to have a high heart rate and breathe heavily post-race…
Factors that affect the Rate of Respiration
1) Concentration of reactants- if the reactants (Glucose and O2) are limited in
concentration, aerobic respiration will be limited and the body may switch to an
alternative pathway.
2) Temperature- as temperature increases, the rate of respiration increases.
Aerobic Respiration
Glycolysis:
Link reaction:
Krebs Cycle:
Oxidative Phosphorylation and Electron Transport Chain: