Unit 4: Chapter 18 Flashcards
Is Digestive System Catabolic or Anabolic process?
Ctabolic: break down to smaller molecules
Stages of Digestive System
- Polymers broken down into smaller subunits in digestive system
- Simple subunits are further broken down to activated carrier, Acetyl CoA
- Acetyl CoA is oxidized to CO2, coupled to production of large amounts of ATP
Pyruvate Dehydrogenase Complex
Forming acetyl coenzyme A from pyruvate
How is pyruvate dehydrogenase complex regulated?
phosphorylation and dephosphorylation
Acetyl CoA (Coenzyme A)
- active carrier carrying acetyl groups
- fuel for citric acid cycle
- 2 carbon acetyl unit
Under aerboic conditions (O2), ______ enters ________ where it is converted to acetyl CoA
pyruvate; mitochondria
Where is acetyl CoA formed?
Mitochondrial matrix via pyruvate dehydrogenase complex
Acetyl CoA cannot enter two membrane of mitochondria
Structure of Acetyl CoA
ADP, hydrocarbon tail, acetyl group (acetyl group contains thioester bond which is very high energy rich bond)
SH group forms ____ bond with acetyl CoA
thioester
Thioester bonds
Have high standard free energy of hydrolysis so will release energy and can donate their acyl group to a variety of acceptors
Pyruvate dehydrogenas complex
Preparing citric acid cycle with product of acetyl CoA
5 enzymes in mitochondrial matrix enzyme
Links glycolysis to citric acid cycle
What are E1, E2, E3 involved in pyruvate dehydrogenase complex?
Involved in converting pyruvate to acetyl CoA (catalytic, break down)
Regulation of pyruvate dehydrogenase complex
- Pyruvate dehydrogenase kinase: add phosphate to inactivate
- Pyruvate dehydrogenase phosphatase: removes phosphate to activate
- Energy charge
Overall reaction equation of pyruvate dehydrogenase complex
pyruvate + CoA + NAD+ –> acetyl CoA + CO2 + NADH + H+
Is pyruvate dehydrogenase complex reversible or irreversible reaction?
Irreversible reaction
Acetyl CoA cannot be made into pyruvate and glucose
Pyruvate dehydrogenase complex (E1)
Prosthetic group:
Reaction catalyzed:
Prosthetic group: TPP
Reaction catalyzed: Oxidative decarboxylation of pyruvate
Dihydrolipoyl tranacetylase (E2)
Prosthetic group:
Reaction catalyzed:
Prosthetic group: Lipoamide
Reaction catalyzed: Transfer of acetyl group of CoA
Dihydrolipoyl dehydrogenase (E3)
Prosthetic group:
Reaction catalyzed:
Prosthetic group: FAD
Reaction catalyzed: Regeneration of oxidized form of lipoamide