Life is a nonequilibrium phenomenon: Metabolism provides a continuous supply of energy that drives nearly all cellular processes. However, very little is known about how much energy different cellular processes use, i.e., their energetic costs. The most direct experimental measurements of these costs involve modulating the activity of cellular processes and determining the resulting changes in energetic fluxes. In this review, we present a flux balance framework to aid in the design and interpretation of such experiments and discuss the challenges associated with measuring the relevant metabolic fluxes. We then describe selected techniques that enable measurement of these fluxes. Finally, we review prior experimental and theoretical work that has employed techniques from biochemistry and nonequilibrium physics to determine the energetic costs of cellular processes.

中文翻译：

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剖析通量平衡以测量细胞生物学中的能量成本：技术和挑战

生命是一种非平衡现象：新陈代谢提供持续的能量供应，驱动几乎所有的细胞过程。然而，人们对不同细胞过程使用多少能量（即它们的能量成本）知之甚少。对这些成本最直接的实验测量涉及调节细胞过程的活动并确定由此产生的能量通量的变化。在这篇综述中，我们提出了一个通量平衡框架，以帮助设计和解释此类实验，并讨论与测量相关代谢通量相关的挑战。然后我们描述了能够测量这些通量的选定技术。最后，我们回顾了之前的实验和理论工作，这些工作采用了生物化学和非平衡物理学的技术来确定细胞过程的能量成本。