overview of cellular respiration section 4.4 cellular respiration makes atp by breaking down sugars....
Post on 03-Jan-2016
213 Views
Preview:
TRANSCRIPT
Overview of Cellular Respiration Section 4.4Cellular respiration makes ATP by breaking
down sugars.If a step requires oxygen, it is called aerobic.If a step occurs in the absence of oxygen, it
is called anaerobic.It takes place in three steps:
GlycolysisKrebs cycleElectron transport chain
Cellular respiration The equation for cellular respiration is:C6H12O6 + 6 O2 6 H2O + 6 CO2 + energy
The equation for photosynthesis is:6 H2O + 6 CO2 + light energyC6H12O6 + 6
O2
GlycolysisIs anaerobicOccurs in the cytoplasmOne 6 carbon glucose molecule is broken
down into two three carbon pyruvate molecules.
Produces 2 ATP molecules
Krebs CycleIs aerobicOccurs in mitochondriaPyruvate is broken down
One 2 carbon molecule 1 CO2 moleculeHigh energy electrons
CoEnzyme A bonds to the 2 carbon molecule
Krebs CycleAcetyl CoA enters the Krebs cycle (2C)Combines with a 4 carbon
molecule to form citric acid (6C)
Loses a CO2 (5C)
Loses another CO2 (4C)Combines with acetyl CoA.Produces 2 ATP
Electron Transport ChainIs aerobicOccurs in mitochondriaNADH and FADH2 donate electrons and
transport hydrogen ions.Produces 34 ATP moleculesHydrogen ions and electrons combine with
oxygen to produce water.
Aerobic respirationAerobic respiration can produce up
to 38 ATP molecules from 1 molecule of glucose.
Most ATP is produced in the electron transport chain.
Anaerobic RespirationAlso called fermentationIn the absence of oxygenIf there is no oxygen to accept electrons or
hydrogen ionsNADH and FADH2 cannot be converted
to NAD+ and FAD2+
Citric acid is not broken down in the Krebs cycle
Acetyl CoA cannot enter the Krebs cycle
Anaerobic respirationPyruvate has to be broken down another
way.In yeasts:
Pyruvate ethanol and CO2
Produces 2 ATP moleculesIn animals:
Pyruvate lactic acidProduces 2 ATP molecules
top related