Question

There are 2 different pathways that pump a different number of H⁺ across the membrane and therefore a different number of ATP.

a) electron transport chain complexes

b) photosystem components

c) metabolic reactions

d) all of the above

Answer 1

In cellular respiration, ATP is primarily produced by the electron transport chain and chemiosmosis, which pump H+ across the membrane and use the resulting gradient to power ATP synthase, converting ADP to ATP.

Step-by-step explanation:

In cellular respiration, two pathways are central in the process of producing adenosine triphosphate (ATP), primarily through oxidative phosphorylation. These are the electron transport chain (ETC) and chemiosmosis. The electron transport chain consists of a series of electron carriers embedded in the inner mitochondrial membrane, which pass electrons down the chain, resulting in the pumping of hydrogen ions (H+) across the membrane, creating an electrochemical gradient. This gradient's potential energy is harnessed by ATP synthase during chemiosmosis to convert adenosine diphosphate (ADP) into ATP, thereby providing the energy that the cells need to function.

The electron transport chain can pump varying numbers of H+ ions depending on the species, creating a gradient that ATP synthase utilizes to produce ATP. This is a critical step in the catabolism of glucose, with the maximum yield of ATP from glucose via oxidative phosphorylation being around 34 ATP, in addition to the ATP made by substrate-level phosphorylation for a total of approximately 38 ATP per molecule of glucose.