QCM : Fundamentals of Bioenergetics — 9 questions

Explication

Energy is defined as the capacity to do work, which is fundamental in driving biochemical processes. Entropy measures the degree of molecular disorder or randomness within a system. These definitions are explicitly provided in the course material, making option 0 the correct choice.

Explication

The correct answer is -7.3 kcal/mol, as explicitly stated in McKee and McKee (2020), representing the standard free energy change for ATP hydrolysis under physiological conditions. This value is widely accepted in biochemistry as the typical free energy released when ATP is hydrolyzed to ADP and Pi, and is a key parameter for understanding energy transfer in cells.

Explication

Reaction coupling's main role is to enable unfavorable reactions to proceed by pairing them with favorable ones, such as ATP hydrolysis, so that the overall free energy change becomes negative, making the process spontaneous.

Explication

The standard free energy change of ATP hydrolysis (~ -7.3 kcal/mol) was first accurately measured and established in the 1960s, which was a pivotal period in bioenergetics research. This value became fundamental in understanding energy transfer in biological systems.

Explication

NADH and FADH2 are electron carriers that transfer high-energy electrons to the electron transport chain, facilitating ATP synthesis. ATP transfers phosphoryl groups to other molecules to provide energy for cellular processes. NADPH mainly supplies reducing power for biosynthesis, not energy production. Therefore, the primary similarity is that NADH and FADH2 transfer electrons, while ATP transfers phosphoryl groups, making option 0 correct.

Explication

McKee and McKee are credited with defining and explaining the fundamental principles of bioenergetics, including energy, entropy, and Gibbs free energy, as outlined in their 2020 work.

Explication

The hydrophobic effect causes the spontaneous exclusion of water from non-polar regions, leading to a decrease in free energy (negative ΔG), which drives membrane formation and protein folding processes.

Explication

NADH is used in cellular respiration by donating high-energy electrons to the electron transport chain, which drives the production of ATP through oxidative phosphorylation. This process is fundamental in energy transfer within cells, making it the correct application of NADH in energy production.

Explication

ATP's ability to transfer its phosphoryl group efficiently is primarily due to the resonance stabilization of its hydrolysis products and the electrostatic repulsion among its negatively charged phosphate groups. These features make the hydrolysis of ATP highly exergonic, facilitating phosphoryl transfer to other molecules.