5.7.7 The role of Coenzymes Flashcards
What is a coenzyme?
A molecule that helps an enzyme carry out its function but is not used in the reaction itself
What is coenzyme A’s role?
It binds to the remainder of the pyruvate molecule (2C) to form acetyl coA
It then supplies the acetyl group to the Krebs cycle where it is used to continue aerobic respiration
What are the roles of NAD and FAD
It plays a critical role in aerobic respiration as hydrogen carriers
What happens when hydrogen atoms become available at different points in respiration?
NAD and FAD accept these hydrogen atoms
What do hydrogen atoms consist of?
A hydrogen ion and a hydrogen electron
What is it called when coenzymes gain a hydrogen?
They are reduced
What is the way to remember redox reactions?
OIL RIG: oxidation is loss reduction is gain
Where do NAD and FAD transfer the hydrogen atoms to?
To the electron transport chain on the inner mitochondrial membrane - the site where hydrogens are removed from the coenzymes
What happens when hydrogen atoms are removed?
The coenzymes are oxidised
Why are hydrogen ions and electrons important in the electron transport chain?
As they play a role in the synthesis of ATP
Where do electrons from reduced NAD and reduced FAD go?
They are given to the elctron transport chain
What does the electron transport chain do?
It drives the movement of these hydrogen ions (protons) across the inner mitochondrial membrane into the intermembrane space, creating a proton gradient (there are more hydrogen ions in the intermembrane space)
The movement of hydrogen ions down the proton gradient, back into the mitochondrial matrix, gives the energy required for ATP synthesis
What happens to hydrogen ions from reduced NAD and reduced FAD?
They are released when the electrons are lost
What are the sources of reduced NAD
2x1=2 from glycolysis
2x1=2 from the link reaction
2x3=6 from the Krebs cycle
What are the sources of reduced FAD?
2x1=2 from the Krebs cycle
