The following is a selection of student opinion on the exothermic bond breaking misconception. The comments were received at the end of the 2nd survey outlined in: Jour. Chem. Educ. 2004. 81, 523, and following a review of the bond breaking misconception.
"I never thought that this concept that I know of ATP could be wrong. Suspicious about books now."
"I remember being very confused about the energy release from ATP when learning about it first in CEGEP (Quebec junior college equivalent), then in university. It didn't make sense to me and conflicted with the basic rules I had learned in my chemistry courses. However, I guess I just accepted it because that was what was written in all of the textbooks as well."
"Though the correct information about bond breaking and formation may have been given throughout high school and CEGEP science classes, the terminology and the concept were not fully explained, leaving a vague picture in my mind, therefore certain misconceptions in these scenarios. The fact that the body uses ATP as an energy source leaves me with the impression that this energy comes about via bond breakage of the P-group. This misconception was therefore applied to bond breakage in general."
"In CEGEP I remember doing a few problems that showed the correct picture of the energy changes associated with bond breaking . That was before ATP was introduced to us which then mislead my thinking. From then on I believed that energy was released when bonds were broken."
"I was under the impression that in exothermic reactions bonds released energy when broken. I was taught in high school that forming bonds required some energy. I was not make aware of this discrepancy until last Wed. when Prof. G.. told us ? made me feel really stupid."
"Thanks for clearing things up."
"The way bio-books word the ATP example leads one to believe that it is the breaking of ATP that gives energy and the formation of ADP is a bi-product."
"It is in CEGEP biology that I was made to believe that only ATP would release energy when its bonds were broken."
"I find that in all the classes I've been through, none of my teachers took the time to explain correctly how the process worked. Maybe it has been mentioned in my chemistry classes (CEGEP), but so quickly that it didn't stick."
"I guess the high school and college teachers are trying to simplify chemistry."
"Since I did not take my high school biology course, there was not much of a change for me to be confused at that time. I had a good chemistry teacher in HS who made it clear that energy was involved in breaking bonds but I never applied it to biology until biology in university which is where I became confused for some reason. I didn't associate the two energies in my mind. There was the energy involved in breaking the bonds which was somehow magically different from the "energy released" using the ATP example. Now I am still a little confused, but hoping that it will get better."
"The correct picture of energy changes associated with bond making and breaking was presented in energy science class, however, it did not seem to apply to ATP, in any of these classes. Nor did I question it, although it did not follow with the theory for every other bond making/breaking reactions."
"I cannot believe it's only after so many (5) years of chemistry and biology that the connection has been made in my head between activation energy and what this means in terms of energy input for bond hydrolysis."
"The incorrect picture, I believe was shown accidentally in CEGEP biology. Biology professors, even those that are intimately familiar with the chemistry, don't want to go into too much detail in a biology course. As a result students are often presented with something like:
Since the professor doesn't put in the water in the reaction, the correct chemistry is obscured."
"University is not about learning anymore. It's about getting a paper."
"I am very pleased to have received the correct information regarding the input and release of energy upon the breaking and making of bonds. As students, we tend to believe whatever our teachers and textbooks us of, and unfortunately that information is not always correctly given."
"I think that you are doing a wonderful thing, Prof.G.. in trying to clear this misconception up. I wish there were more professors like you who are willing to make important changes to the curriculum which obviously affect our education and the education of others."
"I don't think any of my professors or teachers actually stated something that was incorrect about the release of energy in certain reactions. However I came away with the wrong impression probably because they tried to simplify their explanations and it ended up confusing me"
"The CEGEP chemistry courses did provide good information. It was I who forgot. In biology everything was over simplified by the instructors' notes. But by reading Campbell you got a more detailed picture, although it wasn't required as a text."
"No teacher throughout my academic career ever emphasized systematically the energy changes. This has lead to my own misconceptions of the course material. This does not suggest that my teachers did not understand the concept as you do."
"I knew that it takes energy to break bonds, but the term "high-energy phosphate bond" intuitively makes one think that energy is immediately available upon breaking the bond. I think the notion of high energy and instability needs to be stressed more."
"I have always known that bond breaking involved absorbing energy and not releasing energy. This was made very clear in all my high school chemistry courses."
"This is a good exercise, if scientists are not as accurate as science is, misconceptions will prevail, but so will people like you to challenge them."
"While in retrospect this concept was correctly taught in general chemistry, the point concerning ATP and the phrase "high energy phosphate bond" was never clarified. From that phrase it is very easy to infer that the breaking of an ATP bond releases energy."
"In HS chemistry we were taught that bond breaking was endothermic and bond making was exothermic, but it was not reinforced. We were often taught that it was logical for bond making to require energy and thus became confused. We were also taught the simple idea of ATP breakdown in HS biology and that 'the breakdown of ATP releases energy'"
"In this course it was the first time I really understood the energy changes associated with ATP."
"In biology classes both at the high school and university level, hydrolysis reactions are taught in such a way that the student is led to believe that the bond itself is the source of the energy, that the energy is actually 'stored in the bond'."
845 Sherbrooke St. W. Montreal, Quebec H3A 2T5 tel:514-398-4455
© 2005 McGill University