Sears Duane W, Thompson Scott E, Saxon S Robin
From the Department of Molecular, Cellular, and Developmental Biology, University of California Santa Barbara, Santa Barbara, California 93106-9610.
Biochem Mol Biol Educ. 2007 Mar;35(2):105-18. doi: 10.1002/bmb.29.
Adaptive chemical behavior is essential for an organism's function and survival, and it is no surprise that biological systems are capable of responding both rapidly and selectively to chemical changes in the environment. To elucidate an organism's biochemistry, its chemical reactions need to be characterized in ways that reflect the normal physiology in vivo. This is a challenging experimental problem because biological systems are inherently complex with myriads of interlinked chemical networks orchestrating processes that are mostly irreversible in nature. One successful approach for simplifying the study of biochemical reactions is to analyze them under controlled reversible equilibrium conditions in vitro that approximate the range of physiological conditions found in vivo. Because this approach has helped elucidate some of the chemical mysteries of complex biological systems, many topics presented in modern biochemistry courses are essentially rooted in the chemistry of reversible equilibrium reactions. Since most undergraduate biochemistry courses typically require students to complete year-long general and organic chemistry courses, biochemistry instructors may assume that entering students have sufficient understanding of basic reversible equilibrium chemistry to move forward into more advanced biochemical topics. However, this assumption is at odds with our experience in that many entering students seem confused by the conventions, language, symbolic formalism, and/or mathematical tools normally use to describe reversible equilibrium reactions. Part of the problem here may stem from how certain basic chemical concepts are taught (or are not taught) in their prerequisite chemistry courses. Here, we identify some conceptual barriers that many students seem to confront and we discuss instructional strategies designed to help students "connect the dots," so to speak, and better understand how dynamic biological processes can be analyzed in terms of reversible equilibrium chemistry.
适应性化学行为对于生物体的功能和生存至关重要，生物系统能够对环境中的化学变化做出快速且选择性的反应也就不足为奇了。为了阐明生物体的生物化学，需要以反映体内正常生理学的方式对其化学反应进行表征。这是一个具有挑战性的实验问题，因为生物系统本质上是复杂的，有着无数相互关联的化学网络协调着本质上大多不可逆的过程。简化生物化学反应研究的一种成功方法是在体外可控的可逆平衡条件下对其进行分析，这些条件近似于体内发现的生理条件范围。由于这种方法有助于阐明复杂生物系统的一些化学奥秘，现代生物化学课程中呈现的许多主题本质上都源于可逆平衡反应的化学。由于大多数本科生物化学课程通常要求学生完成为期一年的普通化学和有机化学课程，生物化学教师可能会认为入学的学生对基本的可逆平衡化学有足够的理解，从而能够推进到更高级的生物化学主题。然而，这种假设与我们的经验相悖，因为许多入学学生似乎对通常用于描述可逆平衡反应的惯例、语言、符号形式主义和/或数学工具感到困惑。这里问题的一部分可能源于某些基础化学概念在其先修化学课程中的教学方式（或未教学的方式）。在此，我们识别出许多学生似乎面临的一些概念障碍，并讨论旨在帮助学生“融会贯通”的教学策略，可以说，以便更好地理解如何根据可逆平衡化学来分析动态生物过程。
