MCAT Chemistry Question — Thermodynamics Law

  • Reviewed By: Liz Flagge
  • The human body takes biological monomers in the form of amino acids and sugars and builds highly complex physiological structures from them. As such, the human body’s relationship with the second law of thermodynamics can best be described by which of the following:

    A) The human body is an example of how biological systems are not part of the domain of the second law of thermodynamics, since they decrease entropy through anabolic processes.

    B) There is an equilibrium between anabolism and catabolism in the human body, thus it falls under the second law of thermodynamics by not increasing entropy.

    C) The human body follows the second law of thermodynamics by creating decreasing entropy within the system by increasing the entropy of the environment.

    D) It is impossible to relate thermodynamic laws to complex physiological systems.

    Explanation

    Living things don’t get a free pass when it comes to thermodynamics. The human body gets its energy by taking highly organized molecules (imagine the rings of a sugar molecule) and turning them into disorganized things (breathing out CO2 as waste). Thus, the decrease in entropy that is seen in anabolic processes in the human body comes at the expense of increasing disorder in the rest of the universe, making (C) the right answer.

    A, D: These are both false. Living systems are governed by the same rules of chemistry as every other chemical system.

    B: While (B) may occasionally be true, it need not be. Most notably in a growing child or adolescent, there will be more anabolism than catabolism as the body grows.

    Want more MCAT practice?

    We’ve got options for every schedule and learning style!

    From the best online MCAT course created by top instructors with 524+ MCAT scores to the most representative full-length practice exams and private tutoring, we can custom tailor your MCAT prep to your goals!

    Not sure which option is right for you? Schedule a free MCAT consultation with an MCAT expert using the form below. No obligation, just expert advice.

    Schedule My Free Consultation

    MCAT is a registered trademark of the Association of American Medical Colleges (AAMC), which is not affiliated with Blueprint.

    Leave a Reply

    Your email address will not be published. Required fields are marked *