chemical pathways cellular respiration (aerobic) – process that releases energy by breaking down...
TRANSCRIPT
CELLULAR RESPIRATIONChemical Pathways
Cellular Respiration (aerobic) – process that releases energy by breaking down glucose and other food molecules; O2 is required
6O2 + C6H12O6 6CO2 + 6H2O + ATP3 Major sets of reactions – glycolysis, Krebs Cycle, electron transport chain
Fermentation (anaerobic) – process that releases energy from food without O2 – Fig. 9-4
2 Major sets of reactions – glycolysis, fermentation
NADH – an electron carrier molecule
ANAEROBIC RESPIRATIONFERMENTATION
Glycolysis – breakdown of glucose to
produce: 2 pyruvic acid, 2 NADH, **net gain of 2 ATP
Glycolysis
http://www.youtube.com/watch?v=3GTjQTqUuOw
ANAEROBIC RESPIRATIONFERMENTATION
Fermentation – conversion of pyruvic acid to some end product
** no ATP produced
ANAEROBIC RESPIRATIONFERMENTATION
Lactic acid fermenation – end product is lactic acid (ex. Animal cells, lactic acid bacteria)
ANAEROBIC RESPIRATIONFERMENTATION
Alcoholic fermentation – end products are ethanol & CO2 (ex. Bacteria & yeast)
ANAEROBIC RESPIRATIONFERMENTATION
**For each molecule of glucose only 2 ATP are produced during anaerobic respiration.**
AEROBIC RESPIRATION
Glycolysis – exact same steps as in anerobic respiration; takes place in the cytoplasm; At the end of glycolysis approximately 90% of the energy is still stored in pyruvic acid moleculesThese two pyruvic acid molecules will enter the Krebs Cycle (citric acid cycle)
AEROBIC RESPIRATION
Krebs cycle (citric acid cycle) – the two pyruvic acids molecules that are products of glycolysis are broken down in a series of energy-extracting reactionsTakes place in the matrix of the mitochondria
AEROBIC RESPIRATION
Krebs cycle (con’t)1. Citric Acid Production – pyruvic acid is completely oxidized to produce:
a. 2 NADHb. 2 CO2
c. 2 Citric Acid molecules
AEROBIC RESPIRATION
Krebs cycle (con’t)2. Energy extraction – series of
chemical reactions (cycle) to produce (for each pyruvic acid)
a. 1 ATP (2 ATP total)b. 3 NADH (6 NADH total)c. 1 FADH (2 FADH total) d. 2 CO2 (4 CO2 total)
http://www.youtube.com/watch?v=KAjUsiZWywk&feature=related
AEROBIC RESPIRATION
Electron Transport Chain – uses the high energy electrons from glycolysis and the Krebs cycle to synthesize ATP from ADP and Pi
MOST of the energy produced from the breakdown of glucose occurs here (32/34 ATP molecules)
O2 is the final electron acceptor
AEROBIC RESPIRATION
***For each molecule of glucose, 36/38 ATP are produced during aerobic respiration***
***Much more energy efficient than anaerobic respiration****
RESPIRATION OF FATS & PROTEINS
Fats and proteins are broken down at various points along respiratory pathway
Proteins produce about the same amount of ATP as glucose
Fats produce about twice as much energy as glucose
ENERGY & EXERCISE
The body uses ATP from 3 basic sources; ATP stored in muscle cells, and ATP produced by aerobic & anaerobic respiration
The ATP stored in muscle cells only lasts for the first few seconds of activity.