This article presents a problem-based learning (PBL)
approach to teaching elementary biochemistry to undergraduate students. The activity was based on “the foods we eat.”
It was used to engage students’ curiosity and to initiate learning about a subject that could be used by the future teachers
in the high school. The experimental activities (8–12 hours)
were related to the questions: (i) what does the Benedict’s
Reagent detect? and (ii) What is determined by glucose oxidase (GOD)? We also ask the students to compare the results
with those obtained with the Lugol reagent, which detects
starch. Usually, students inferred that the Benedict reagent
detects reducing sugars, while GOD could be used to detect
glucose. However, in GOD assay, an open question was left,
because the results could be due to contamination of the
sugars (particularly galactose) with glucose. Though not
stressed, GOD does not oxidize the carbohydrates tested and
all the positive results are due to contamination. The activities presented here can be easily done in the high school,
because they are simple and non-expensive. Furthermore, in
the case of Benedict reaction, it is possible to follow the
reduction of Cu (II) “macroscopically” by following the formation of the brick-orange precipitate. The concrete observation of a chemical reaction can motivate and facilitate
students understanding about chemistry of life. V C 2013 by
The International Union of Biochemistry and Molecular Biology, 42(1):81–87, 2014
This article presents a problem-based learning (PBL)approach to teaching elementary biochemistry to undergraduate students. The activity was based on “the foods we eat.”It was used to engage students’ curiosity and to initiate learning about a subject that could be used by the future teachersin the high school. The experimental activities (8–12 hours)were related to the questions: (i) what does the Benedict’sReagent detect? and (ii) What is determined by glucose oxidase (GOD)? We also ask the students to compare the resultswith those obtained with the Lugol reagent, which detectsstarch. Usually, students inferred that the Benedict reagentdetects reducing sugars, while GOD could be used to detectglucose. However, in GOD assay, an open question was left,because the results could be due to contamination of thesugars (particularly galactose) with glucose. Though notstressed, GOD does not oxidize the carbohydrates tested andall the positive results are due to contamination. The activities presented here can be easily done in the high school,because they are simple and non-expensive. Furthermore, inthe case of Benedict reaction, it is possible to follow thereduction of Cu (II) “macroscopically” by following the formation of the brick-orange precipitate. The concrete observation of a chemical reaction can motivate and facilitatestudents understanding about chemistry of life. V C 2013 byสหภาพนานาชาติด้านชีวเคมีและอณูชีววิทยา 42 (1): 81-87, 2014
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