Glucose as the sole metabolic fuel: The possible influence of formal teaching on the establishment of a misconception about energy‐yielding metabolism among students from Rio de Janeiro, Brazil

Abstract

Energy-yielding metabolism is an important biochemistry subject that is related to many daily experiences and health issues of students. An adequate knowledge of the general features of EYM is therefore important, both from an academic and social point of view. In a previous study, we have shown that high-school students present the misconception that carbohydrates, especially glucose, are the sole metabolic fuel for ATP production by human cells. In the present work, we investigated the possible origins of the occurrence of this misconception among students. The analysis of students' answers to questionnaires indicated that the misconception appears as soon as in the 8th grade and remains unchanged throughout subsequent school years. The analysis of grade textbooks showed that the misconception is likely to be a consequence of the teaching of nutrition in the 8th grade, when a single function is emphasized for each nutrient. The energetic function is mainly associated with carbohydrates, while proteins and lipids are considered structural and storage molecules, respectively. An extreme similarity was observed between students' knowledge of nutrient's function and textbook contents. Analysis of high-school textbooks suggested that the misconception would be reinforced because of the detailed teaching only of glucose metabolism, with rare mention of lipids or amino acids as metabolic fuels. The consequences of that approach are discussed and suggestions are made on an alternative teaching of energy-yielding metabolism.Keywords: Misconception, energy-yielding metabolism, textbooks analysis. Energy-yielding metabolism (EYM)1 is an important biochemistry subject for the comprehension of how the whole organism functions. The metabolism is also deeply related to students' daily experiences such as diets, physical exercise, puberty, and adolescence. It is also relevant to the understanding of common diseases such as diabetes, for instance. Moreover, the media constantly exerts pressure on youngsters, stimulating them to go on countless diet and exercise programs. Obesity cases have been increasing among young individuals in Brazil and in other developing countries [1]. Although the data regarding developing countries are scarce, the reports on steroid anabolic hormones abuse among young gym members [2] as well as those on trainers who recommend those substances to their pupils are worrisome [3]. Both problems are related to EYM, and its control is likely to benefit from an adequate knowledge of this subject by young individuals.In a previous study, we investigated students' misconceptions about EYM [4]. In that study, undergraduate students, at the early weeks of their courses, were asked to answer questions about the regulation of metabolism in low-carbohydrate diets and fasting, and the results indicated that they are unaware that other molecules besides glucose can be used as fuel for ATP production in human cells. A more explicit attempt to stimulate students to connect EYM and daily experiences proved that even af...

Glucose as the sole metabolic fuel: Overcoming a misconception using conceptual change to teach the energy‐yielding metabolism to Brazilian high school students

“…The difference between the two situations was significant ( X 2 = 8.687, p = 0.0338) . Those results are fully compatible with previous reports showing that the misconception is established in grade school and later reinforced at the first year of high school [].…”

“…Students' misconceptions regarding EYM were characterized on three different occasions. First, students answered the same questionnaire (Q1) used in previous studies [], which was meant to allow comparison of the results obtained with those reported in previous studies. The Q1 was answered anonymously by the students two days before the teaching of the EYM teaching unit (EYM‐TU) and consisted of two objective questions: 1) “What happens to the overall ATP production in an individual fed on a low carbohydrate diet?” and 2) “What happens to the overall ATP production in an individual undergoing prolonged (many days of) fasting?” Students had the same four choices to answer to each question: “I do not know”; “ATP production remains unchanged”; “ATP production increases”; or “ATP production decreases.” Three lines were available after the choices for the students to briefly justify their answers.…”

“…The analysis of high school and grade school textbooks showed that the energy yielding function of nutrients was almost solely attributed to carbohydrates, a vision that is further reinforced by the teaching of the glucose oxidizing pathways in high schools . The influence of formal teaching was made evident by the fact that the students' knowledge of the functions of nutrients reflected almost exactly the information found on textbooks . The pivotal influence of formal teaching was corroborated by the finding that Science and Biology teachers shared that same misconception and were thus likely to teach that view to their students .…”

“…Students expressing that misconception disregard the possibility of ATP production from lipids and amino acids. The analysis of high school and grade school textbooks showed that the energy yielding function of nutrients was almost solely attributed to carbohydrates, a vision that is further reinforced by the teaching of the glucose oxidizing pathways in high schools . The influence of formal teaching was made evident by the fact that the students' knowledge of the functions of nutrients reflected almost exactly the information found on textbooks .…”

Uncovering students’ misconceptions by assessment of their written questions

“…Several studies demonstrated misconceptions prevailing throughout courses [6–9]. Current methods to test conceptual understanding and uncover misconceptions include: multiple choice questions (MCQs) with or without written explanations [4, 6, 10–17]; MCQs including a confidence test [18]; open questions [19]; generating MCQ questions by the student [20]; drawing [21] or selecting drawings [22]; individual interviews [21, 23]; laboratory instructions with or without (verbal) predictions of the outcome of the experiment [24]; online self-directed E-learning modules [25]; or in-depth interviews with teachers to explore their perceptions of student’s misconceptions [3]. …”