Question

Experimental evidence supporting the chemiosmotic hypothesis was gathered by using artificial vesicles containing a protein that can pump protons in one direction across the vesicle membrane to create a proton gradient. Which protein was used to generate the gradient in a highly controlled manner?

1) ATP synthase
2) Cytochrome c oxidase
3) NADH dehydrogenase
4) Proton pump

Answer 1

The protein used to generate a proton gradient in artificial vesicle experiments for chemiosmosis is a proton pump, which actively transports hydrogen ions to create an electrochemical gradient that ATP synthase utilizes for ATP synthesis.

Step-by-step explanation:

The protein used to generate a proton gradient across artificial vesicle membranes in a controlled manner, as part of experimental evidence for the chemiosmotic hypothesis, is proton pump. This process involves the active transport of hydrogen ions (protons) against their concentration gradient, resulting in the creation of an electrochemical gradient. This gradient subsequently drives the production of ATP as protons flow back across the membrane through the enzyme complex ATP synthase, which operates similarly to a turbine, using the mechanical energy from the flow of protons to synthesize ATP from ADP and inorganic phosphate (P₁).

The proton pumps that are part of the electron transport system (ETS) include Complex I (NADH dehydrogenase), Complex III, and Complex IV (cytochrome c oxidase). However, when specifically referring to a controlled experimental setting with artificial vesicles, a generic proton pump may be used rather than these specific complexes.