Describe why these statements are true. A. The proteins of the electron-transpor
ID: 81949 • Letter: D
Question
Describe why these statements are true.
A. The proteins of the electron-transport chain remove a pair of high-energy electrons from the cofactors NADH and FADH2, after which the electrons move across the inner mitochondrial membrane to maintain the electrochemical gradient.
B. Gluconeogenesis is a linear reaction pathway that the cell employs to generate glucose from pyruvate and it is the reverse of the reactions in the glycolytic pathway. However, there are some differences between the two pathways.
I am a little lost with how to answer this question help please.
Explanation / Answer
a) Electrons from NADH and FADH2 are transferred to the complex I and complex II of the electron transport chain. The electrons from complex II are passed via ubiquinone to complex III and complex IV. The electrons flow through these protein complexes is associated with transfer to proton from matrix to the inter membrane space. This makes the intermembrane space more positive and acidic as compared to the matrix resulting in proton chemical (pH gradient) and electron gradient across the memrbane. Since inner mitochondrial membrane is impermeable to the protons, the protons enter the matrix again through the proton channels of complex V resulting in ATP synthesis. This is how, the electron flow through ETS maintains the electrochemical gradient.
b) Gluconeogenesis refers to the synthesis of glucose from pyruvate in liver cells. Glycolysis is the breakdown of glucose into two molecules of pyruvate. These two process have common resversible reactions. However, gluconeogenesis has some reactions catlysed by enzymes Pyruvate Carboxylase, Phosphoenolpyruvate,Fructose 1,6 Bisphosphatase and Glucose 6-phosphatase which are exclusive to this pathway only i.e. these enzymes do not operate in glycolysis.