cellular respiration obtain energy from the degradation of sugars uses oxygen and produces co 2 many...
TRANSCRIPT
Cellular Respiration Obtain energy from the degradation of sugars Uses Oxygen and produces CO2
Many steps take place in the mitochondria of cells
Complementary process to photosynthesis Will recognize many of the same molecules
Oxidation-Reduction reactions Type of reaction when an electron is
transferred from one atom or molecule to another Electron donor is reducing agent Electron acceptor is oxidizing agent The addition of electron to a molecule or atom is
called reduction
Energy is released when electrons are transferred to lower energy state molecules Electron transfer chains
Cellular Respiration Mechanisms
3 Stages Glycolysis-happens in cytosol of cell Krebs cycle-happens in matrix of mitochondria Electron transport and oxidative phophorylation-cristae
Glycolysis Means “sugar splitting”-glucose is split into
Pyruvate First step of respiration Broken into two stages
Energy investment phase-uses 2ATP Energy Payoff Phase-Yields 4 ATP +2 NADH Net of 2 ATP
Energy Investment Phase Begins with Glucose 2 ATPs are used to phosphorylate Carbons 1
and 6 Activated intermediates
Isomerase converts glucose to fructose structure Isomerase is enzyme that changes one molecule to
an isomer
Eventually yields 2 molecules of glyceraldehyde phosphate Enters energy payoff phase
Fig. 9-8
Energy investment phase
Glucose
2 ADP + 2 P 2 ATP used
formed4 ATP
Energy payoff phase
4 ADP + 4 P
2 NAD+ + 4 e– + 4 H+ 2 NADH + 2 H+
2 Pyruvate + 2 H2O
2 Pyruvate + 2 H2OGlucoseNet
4 ATP formed – 2 ATP used 2 ATP
2 NAD+ + 4 e– + 4 H+ 2 NADH + 2 H+
Energy Payoff Phase Starts with Glyceraldehyde phosphate
2 for every glucose
Enzyme adds phosphate GP while 2 NADH molecules are produces
Phosphates are eventually loss resulting in the production of 4 ATP molecules
The final product is Pyruvate Moves into Krebs cycle
Transition
Once Pyruvate enters Mitochondrion it is converted to Acetyl CoA and CO2
Acetyl CoA is the starting molecule for the Krebs cycle
Fig. 9-10
CYTOSOL MITOCHONDRION
NAD+ NADH + H+
2
1 3
Pyruvate
Transport protein
CO2Coenzyme A
Acetyl CoA
Krebs cycle
Completes the oxidation of organic molecules Takes place in matrix of mitochondria Cyclic like Calvin cycle Produces 1 ATP for each acetyl CoA
2 per glucose
Many high energy electrons are saved as 3NADH and FADH2 per cycle
Also produces 2 CO2 molecules per cycle
Fig. 9-12-8
Acetyl CoA
CoA—SH
Citrate
H2O
IsocitrateNAD+
NADH
+ H+
CO2
-Keto-glutarate
CoA—SH
CO2NAD+
NADH
+ H+SuccinylCoA
CoA—SH
P i
GTP GDP
ADP
ATP
Succinate
FAD
FADH2
Fumarate
CitricacidcycleH2O
Malate
Oxaloacetate
NADH
+H+
NAD+
1
2
3
4
5
6
7
8
Fig. 9-11
Pyruvate
NAD+
NADH
+ H+Acetyl CoA
CO2
CoA
CoA
CoA
Citricacidcycle
FADH2
FAD
CO22
3
3 NAD+
+ 3 H+
ADP + P i
ATP
NADH
Transition 2
NADH and FADH2 are used in the electron transport chain Happens in cristae of mitochondrion Uses Oxygen as ultimate electron acceptor