Teaching nutritional biochemistry: an experimental approach using yeast

Abstract

In this report, we present a practical approach to teaching several topics in nutrition to science students at the high school and college freshmen levels. This approach uses baker's yeast (Saccharomyces cerevisiae) as a biological system model. The diameters of yeast colonies, which vary according to the nutrients present in the medium, can be observed, compared, and used to teach metabolic requirements. The experiments described in this report show simple macroscopic evidence of submicroscopic nutritional events. This can serve as a useful base for an analogy of heterotrophic human cell nutrition.

Importance of three physiological models for teaching the carbohydrates metabolism

“…Patro 18 suggested a teaching strategy that combines simple experiments, use of molecular models to distinguish cellular respiration; use of an animated video, questionnaires, and a final evaluation by means of the elaboration of a poster. Alonso & Stella 19 proposed to teach nutrition using yeasts; Figueira and Rocha 20 and Ross et al 21 suggested a problem‐based approach or a role‐playing strategy, respectively. Lubkowitz et al 22 highlighted a series of questions and experiences to follow the path of the carbon atoms in the biosphere.…”

“…Regardless the teaching resources and strategies used to teach the carbon cycle, [17][18][19] the physiological model of blood glucose uptake and homeostasis, 20,[22][23][24][25][26][27][28][29][30] and the physiological model of the availability of metabolites [1][2][3]25,26,32,33 the important thing is that the students manage to construct biochemical meanings inserted in models [35][36][37][38][39] that holistically encompass the CHM.…”

Observación del efecto reductor de N-Acetilcisteína en el metabolismo de levaduras

“…Se extrajo una pequeña porción del paquete, se colocó en 10 ml de agua destilada estéril y se sembró en medio sólido para aislar colonias. Estas colonias son la fuente de inoculo de todos los experimentos, ya que aseguran la ausencia de contaminación [13,14] .…”

“…Observación del efecto reductor de N-Acetilcisteína en el metabolismo de levaduras reemplazados por otros de menor costo como azúcar de mesa, 2% p/v; caldo de carne filtrado 10 % p/v, levadura de cerveza en polvo, suplementos nutricionales de aminoácidos, etc [13,14]. El agar puede ser reemplazado por el ofrecido en comercios de productos dietéticos utilizando la misma concentración.…”