Transcript

CELLULAR RESPIRATION

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

Glycolysis

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

http://www.youtube.com/watch?v=kN5MtqAB_Yc&feature=related

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

RESPIRATION OF FATS & PROTEINS

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.

ENERGY & EXERCISE

ATP produced by anaerobic respiration is used up in about 90 seconds. Oxygen debt is the amount of O2 required to convert lactic acid to glucose.

Aerobic respiration produces the ATP to sustain activities that go on longer. That is why athletes must pace themselves.


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