respiration 4 link and krebs
TRANSCRIPT
2 x 3C pyruvate
2 x 3C triose phosphate
6C hexose bisphosphate
Glucose (6C hexose)
Pyruvate actively pumped into mitochondrial matrix
2x NADH produced from NAD
4x ATP produced
2x ATP used
Glycolysis (cytoplasm)…
Glucose (6C hexose)
6C hexose bisphosphate
2 x 3C triose phosphate
2 x 3C pyruvatePyruvate actively pumped into mitochondrial
matrix
2x ATP used
4x ATP produced
2x NADH produced from NAD
Substrate Level Phosphorylation
• Formation of ATP from ADP and Pi during glycolysis and the Krebs cycle
http://www.northland.cc.mn.us/biology/biology1111/animations/glycolysis.html
http://www.science.smith.edu/departments/Biology/Bio231/glycolysis.html
The Link Reaction
• (i) state that the link reaction takes place in the mitochondrial matrix;
• (j) outline the link reaction, with reference to decarboxylation of pyruvate to acetate and the reduction of NAD;
• (k) explain that acetate is combined with coenzyme A to be carried to the next stage;
Key terms
Decarboxylation and dehydrogenation
• Decarboxylation – removal of a carboxyl group from a chemical compound, usually with hydrogen replacing it
• Dehydrogenation – removal of a hydrogen from a chemical compound
Draw the Link Reaction
• (i) state that the link reaction takes place in the mitochondrial matrix;
• (j) outline the link reaction, with reference to decarboxylation of pyruvate to acetate and the reduction of NAD;
• (k) explain that acetate is combined with coenzyme A to be carried to the next stage;
Pyruvate (3C)
Acetate (2C)
Acetyl CoA (2C)
CO2NAD+NADH
What enzymes are involved?
1. A hydrogen atom is removed from pyruvate
2. A carboxyl group is removed from pyruvate (the carboxyl group will eventually become carbon dioxide)
What type of substance are NAD and Coenzyme A?
The Krebs Cycle
• (l) state that the Krebs cycle takes place in the mitochondrial matrix;• (m) outline the Krebs cycle, with reference to the formation of citrate
from acetate and oxaloacetate and the reconversion of citrate to oxaloacetate (names of intermediate compounds are not required);
• (n) explain that during the Krebs cycle, decarboxylation and dehydrogenation occur, NAD and FAD are reduced and substrate level phosphorylation occurs;
Krebs Cycle
• http://highered.mcgraw-hill.com/sites/007352543x/student_view0/chapter8/how_the_krebs_cycle_works.html
Can You Remember?
6 5 4 4 4 4
NAD NAD ATP FAD NAD
Link Reaction and Krebs Cycle
• http://www.youtube.com/watch?v=KZYtwtNrAm8
• http://www.youtube.com/watch?v=ti6-57yK5RY
• Answer Stretch and Challenge Question P89
• Expand the table P89 to include glycolysis