Question

In order for P. multocida to survive and carry out cellular functions (and cause infection), the energy contained in each molecule of glucose must be converted into ATP. This occurs via the process of chemiosmosis, which couples electron transport to ATP synthesis. This process involves the sequential transfer of elections via a series of protein complexes and carriers found in the bacterial plasma membrane. Recall that electrons move down the chain in a sequential fashion due to the increasing electronegativity of the components of the electron transport chain.

Arrange the components of the electron transport chain in order from least electronegative.

a. O2
b. NADH dehydrogenase
c. Cytochrome b-c1 complex
d. Coenzyme Q
e. Cytochrome c
f. Cytochrome oxidase complex

Answer 1

Components of the electron transport chain (ordered by electronegativity from least electronegative to most electronegative):

NADH dehydrogenase >> Coenzyme Q >> Cytochrome b-c1 complex >> Cytochrome c >> Cytochrome oxidase complex > O2

Step-by-step explanation:

The electron transport chain transfers electrons from donors to acceptors via redox reactions (i.e., where reduction and oxidation occur together), and couples the transfer of electrons with proton transfer (H+ ions) across the membrane. In the electron transport chain, the electrons are transferred from NADH dehydrogenase NADH to oxygen (O2) through a series of transmembrane complexes: NADH-Q oxidoreductase, Q-cytochrome c oxidoreductase and cytochrome c oxidase. In the first place, the reduced form of coenzyme Q (ubiquinone) transports the electrons from the NADH-Q oxidoreductase to the Q-cytochrome c oxidoreductase complex (Cytochrome b-c1 complex). Second, the cytochrome c transports the electrons from this complex (i.e., Cytochrome b-c1 complex) to the Cytochrome oxidase complex, this being the last component in the electron transport chain that is responsible to catalyze the reduction of O2.