Respiration
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Transcript of Respiration
Respiration
OCR Central ConceptsA2 Revision
Energy and respiration
Metabolism– Total of all biochemical reactions needed for an
organism to stay alive– Anabolism + catabolism
Energy needed to do work– Synthesis– Active transport– Movement– Maintenance of body temperature
Photosynthesis and Respiration
Energy transfer processes
Photosynthesis6CO2 + 6H2O in the presence of light energy C6H12O6 + 6O2
RespirationC6H12O6 + 6O2 energy is released 6CO2 + 6H2O
Most energy transferred to ATP originally derived from light energy
Energy and Living Organisms
Transfer of materials and energy in an ecosystem
Adenosine Triphosphate
Small water soluble moleculePhosphorylated nucleotideATPADP = 30.5KJmol-1 energyATPaseATPsynthase
Synthesis of ATP
ATP is formed during respiration (and in photosynthesis
Synthesis of ATP
Mitochondria
Respiration as a REDOX reaction
Oxidation involves
•Addition of oxygen
•Removal of hydrogen
•Loss of electrons
•Release of energy
Reduction involves
•Removal of oxygen
•Addition of hydrogen
•Gain of electrons
•Uptake of energy
Aerobic Respiration
The transfer of chemical potential energy from organic molecules to ATP in living cells.GlycolysisLink reactionKrebs cycleOxidative phosphorylation
Glycolysis
One molecule of glucose is oxidised to two molecules of pyruvate.– Phosphorylation– Lysis– Oxidation
Glucose
Hexose phosphate
Hexose biphosphate
2 X triose phosphate (3C)
2 X pyruvate (3C)
Link Reaction
Pyruvate is– Decarboxylated– Dehydrogenated– Combined with coenzyme A (adenine, ribose,
pantothenic acid)
Pyruvate (3C) + coenzyme A------------------acetyl (2C) coenzyme A
Carbon dioxide
NAD NADred
Krebs Cycle
Each cycle releases– 2CO2
– 1 FADred
– 3NADred
– 1 ATP
Electron Transport Chain
When reduced FAD is oxidised, only two molecules of ATP are formed
Summary of aerobic respiration
* Oxidative phosphorylation
*
Anaerobic Respiration
The Ethanol Pathway
Anaerobic Respiration
Lactate Pathway
The Cori Cycle
Rescues lactate and prevents waste of its chemical bond energyPrevents fall in plasma pH
Respiratory Substrates
Substrate energy density (KJg-1)Carbohydrate 16Lipid 39Protein 17
Bomb calorimeter
Respiratory Quotient
RQ = Volume of carbon dioxide given off Volume of oxygen
taken in
Glucose = 1Lipids = 0.7Protein = 0.9
Investigating Respiration
Respirometer
Effect of temperature on respirationQ10 = rate of reaction at temperature t + 10oC
rate of reaction at a temperature t