Question

It's a yes or no question

Riboflavin (otherwise known as vitamin B,) is used to make Flaven MonoNucleotide (FMN), a critical redox prosthetic group within Complex I. A child suffering from food insecurities (hunger) has an undiagnosed vitamin Bdeficiency (too little vitamin Bin their diet). This child will also have very low FMN production FMN Complex Complex 1 - Normal B, Levels Very Low B, Levels How will this change impact activities of cellular respiration? Except for FMN within Complex I (which is absent), all other molecules in cellular respiration behave as expected a. Will NADH be likely to be oxidized into NAD+ by Complex I? [Select) b. Will Q undergo a redox reaction with FeS group of Complex I? (Select] c. Will Complex I still pump protons? (Select] d. Will NADH be able to be oxidized into NAD+ by complex Il? (Select] e. Will Complex Il be able to accept electrons from Complex I? Select]

Answer 1

The inner mitochondrial membrane harbors a series of electron donors and acceptors that transfers electrons from NADH and FADH₂ to molecular oxygen, reducing it to water molecules. This electron transport is coupled with pumping of electrons from the mitochondrial matrix into the intermembrane space, that generates a proton gradient across the mitochondrial membrane. This proton gradient thus generated,is utilized by ATP synthase to generate ATP from ADP and Pi . The electron transport chain consists of 4 complexes: Complex 1-4.

Complex I: catalyzes transfer of electrons from NADH to FMN, followed by a series of iron sulfur centers and finally to ubiquinone, reducing it to QH₂.

Complex II: It catalyzes transfer of electrons originating from succinate to FAD, followed by Fe-S centers and finally to ubiquinone, reducing it to QH_2.

a. No, Since electrons from NADH are transferred to FMN and this transfer will not take place in deficiency of riboflavin.

b. No, as FMN acts as a bridge for transferring electrons from NADH to Fe-S groups and Q will not receive electrons in deficiency of riboflavin.

c. No, as the energy released during electron transfer is used to pump electrons. In the absence of electron transfer through Complex I no electrons will be pumped across the inner mitochondrial membrane.

d. No, since FMN is the immediate electron acceptor from NADH, deficiency of riboflavin (and hence FMN) will block the oxidation of NADH into NAD⁺