scholarly journals THE EVOLUTION OF THE KREBS CYCLE: A PROMISING THEME FOR MEANINGFUL BIOCHEMISTRY LEARNING IN BIOLOGY

2015 ◽  
Vol 13 ◽  
pp. 9
Author(s):  
C. Costa ◽  
E. Galembeck

INTRODUCTION: Evolution has been recognized as a key concept for biologists. In order to motivate biology undergraduates for contents of central energetic metabolism, we addressed the Krebs cycle structure and functions to an evolutionary view. To this end, we created a study guide which contextualizes the emergence of the cyclic pathway, in light of the prokaryotic influence since early Earth anaerobic condition to oxygen rise in atmosphere. OBJECTIVES: The main goal is to highlight the educational potential of the material whose subject is scarcely covered in biochemistry textbooks. MATERIALS AND METHODS: The study guide is composed by three interrelated sections, the problem (Section 1), designed to arouse curiosity, inform and motivate students; an introductory text (Section 2) about life evolution, including early micro-organisms and Krebs cycle emergence, and questions (Section 3) for debate. The activity consisted on a peer discussion session, with instructors tutoring. The questions were designed to foster exchange of ideas in an ever-increasing level of complexity, and cover subjects from early atmospheric conditions to organization of the metabolism along the subsequent geological ages. RESULTS AND DISCUSSION: We noticed that students were engaged and motivated by the task, especially during group discussion. Based on students’ feedbacks and class observations, we learned that the material raised curiosity and stimulated discussion among peers. It brought a historical and purposeful way of dealing with difficult biochemical concepts. CONCLUSIONS: The whole experience suggests that the study guide was a stimulus for broadening comprehension of the Krebs cycle, reinforcing the evolutionary stance as an important theme for biology and biochemistry understanding. On the other hand, we do not underestimate the fact that approaching Krebs cycle from an evolutionary standpoint is a quite complex discussion for the majority of students. KEYWORDS: Evolution. Krebs cycle. Metabolism learning. Biology. ACKNOWLEDGEMENTS: We thank Capes for financial support.

2007 ◽  
Vol 4 (3) ◽  
pp. 168-180
Author(s):  
Nicolas de Sadeleer

AbstractThe term biodiversity itself was not coined until the 198os, when it was popularised by the eminent Harvard biologist Wilson. Biodiversity entails at the macro level ecosystemic diversity (ecosystems and landscapes), specific diversity (the species of plants, animals and micro-organisms that surround us) and at the micro level it includes genetic diversity. Although less marked than on other continents, Europe's systemic diversity displays a number of particular characteristics. However, Europeans should seriously fear for the future of their wildlife. Indeed, many wild fauna and flora species today are passing through a period of major crisis. As most natural or semi-natural, continental and coastal ecosystems are now undergoing significant modifications as a result of human activity (fiagmentation, isolation, intensification, ... ), animal and plant species are suffering an unprecedented rate of extinction. To make matters worse, this negative trend is compounded by an array of additional threats (poaching, excessive hunting, disturbance inflicted by tourism, collision of birds with power-lines). Last, on a more global scale, global warming and the depletion of the ozone layer risk precipitating much more profound changes to the distribution, structure and functions of European ecosystems. Given that this issue has been identified as a pressing concern by the EC institutions, the aim of the present article is to highlight the different strategies, plans and programs as well as the main directives and regulations that were enacted with the aim of conserving biodiversity.


Author(s):  
Nikmah Amelya Permatasari

This study investigated the significant effect of small group discussion toward students’ presentation skill of hortatory exposition text. The design of the study was quasi experiment. The researcher chose the eleventh grade of SMAN 1 Kebomas which totally consist of 46 students. The sample was divided into two groups. XI-MIPA-1 was as the experiment group and XI-MIPA-2 was as the control group. The data was collected by using tests, pretest and posttest. The research finding showed that there was difference between experiment group who were taught by small group discussion method and control group who were taught by peer discussion. It is proven by the result of sig. (2tailed) is 0.039 and 0.038. The sig. (2tailed) is lower than 0.05 but it closer to 0.05. So, the null hypothesis can be rejected. It means that small group discussion gave positive effects on students’ presentation skill. The researcher concluded that small group discussion gave positive effect on students’ presentation skill. They were better in developing paragraph and better in word choices.


Author(s):  
Татьяна Николаевна Жилина

Введение. Современное образование на разных его уровнях направлено на формирование и развитие высокоинтеллектуальной и творческой личности, обладающей значительным профессиональным потенциалом. Для достижения данной цели требуется высокая квалификация преподавателя в области преподаваемых дисциплин и владение современными методами организации образовательного взаимодействия со студентами. Цель – анализ образовательного потенциала предметного КВНа «Государство: экономико-географическое положение, свойства территории, тип экономики» в развитии профессиональных компетенций бакалавров (направление подготовки 05.03.02 География) и магистрантов (направление 05.04.02 География, программа «Цифровые технологии в географии» профиля «География в общем и профессиональном образовании»). Материал и методы. Представлены результаты опыта подготовки и проведения предметного КВНа на кафедре географии Томского государственного университета с 2013 по 2019 г. При изучении курса «Социально-экономическая география» и проведении предметного КВНа использованы интерактивные методы обучения – метод дискуссии, эвристическая беседа, мозговой штурм, практические работы, метод деловой игры. Метод анкетирования бакалавров и магистрантов-педагогов позволил определить образовательный потенциал мероприятия. Результаты и обсуждение. Выделяются этапы мероприятия, направленные на получение образовательного результата: вводный, когда студенты знакомятся с теоретическим материалом курса, выполняют практические работы и готовятся к КВНу; этап проведения предметного КВНа включает в себя представление от каждой группы результатов исследования по описанию государства, проекта создания предприятия, научно-музыкально-театрализованного представления и решение ситуационных задач. Итоговый этап включает анализ образовательных результатов, где предлагается ответить на вопросы рефлексивного характера, проводятся анкетирование студентов и анализ анкет. Заключение. Образовательный и развивающий потенциал предметного КВНа значителен и выражается в формировании профессиональных компетенций бакалавров и магистрантов указанных направлений; интенсификации процесса усвоения, понимания и творческого использования полученных знаний в решении практических задач; вовлеченности участников и их активного взаимодействия между собой в решении проблем и развитии личной рефлексии и навыков самоанализа при групповой работе; усилении мотивации к изучению дисциплины; формировании позитивного отношения к профессиональной деятельности. Достигается высокий уровень профессиональных компетенций у магистрантов как будущих учителей географии, владеющих современными образовательными технологиями и методиками для организации качественного учебно-воспитательного процесса в образовательных учреждениях разного типа. Introduction. Education nowadays is aimed at the establishment and development of a highly intellectual and creative personality with significant professional potential. Achieving this goal requires high qualification of the teacher in the field of the disciplines taught and his mastery of modern methods of organizing educational interaction with students. Aim and objectives. The main aim of the research being done is to analyze the educational potential of the thematic club of the funny and resourceful under the name of «State: economic and geographical position, the properties of a territory, a type of economy» in forming professional competences of students studying in the direction of training Geography 05.03.02 and master students studying in accordance with the master program «Digital technologies in geography», the profile «Geography in general and professional education». Material and methods. This article uses the research data set produced by organizing and holding a thematic KVN at the Department of Geography of NR TSU in the period from 2013 to 2019. We used group discussion, heuristic conversation, brainstorming, practical works and other interactive teaching methods within the course «Social and economic geography» and as part of conducting a thematic KVN. A questioning of bachelors and masters students allowed to determine the educational potential of the event. Results and discussion. Several stages of the event are singled out. During the introductory stage the students are introduced to the theoretical material of the courses, do practical work and prepare for conducting the club of the funy and resourceful when they are given special tasks to fulfill. Holding a thematic KVN includes a presentation of scientific information on characteristics of a state and a project of setting up a company in the territory of the country concerned, which is done by each group of students. The stage also deals with the solution of some situational problems and a scientific, musical and theatrical performance. The final stage of the thematic club is concerned with the analysis of the results obtained where all the participants are offered to answer some questions of a reflexive character. Conclusion. The educational and advanced potential of the thematic club of the funny and resourceful is significant and they are expressed in forming professional competencies in bachelors and masters of the directions concerned. This potential is also characterized by the intensification of the process of acquiring, understanding and creative using of the knowledge obtained to solve practical problems; involvement of all the participants and their active interaction with each other to find solutions to problems; development of personal reflection and self-analysis skills in group work; motivation growth to study a discipline, and formation of a positive attitude to a professional activity. On the basis of the factors mentioned, we can say that a new qualitative level of professional education of master students is achieved. The latter will become geography teachers in the future and will be able to employ modern pedagogical techniques and methods to ensure the quality of an academic and educational process in various educational institutions which is one of the major factors of forming a new generation of teachers and instructors.


Author(s):  
L. Reimer

Most information about a specimen is obtained by elastic scattering of electrons, but one cannot avoid inelastic scattering and therefore radiation damage by ionisation as a primary process of damage. This damage is a dose effect, being proportional to the product of lectron current density j and the irradiation time t in Coul.cm−2 as long as there is a negligible heating of the specimen.Therefore one has to determine the dose needed to produce secondary damage processes, which can be measured quantitatively by a chemical or physical effect in the thin specimen. The survival of micro-organisms or the decrease of photoconductivity and cathodoluminescence are such effects needing very small doses (see table).


Author(s):  
H. S. Kim ◽  
R. U. Lee

A heating element/electrical conduit assembly used in the Orbiter Maneuvering System failed a leak test during a routine refurbishment inspection. The conduit, approximately 100 mm in length and 12 mm in diameter, was fabricated from two tubes and braze-joined with a sleeve. The tube on the high temperature side (heating element side) and the sleeve were made of Inconel 600 and the other tube was stainless steel (SS) 316. For the filler metal, a Ni-Cr-B brazing alloy per AWS BNi-2, was used. A Helium leak test spotted the leak located at the joint between the sleeve and SS 316 tubing. This joint was dissected, mounted in a plastic mold, polished, and examined with an optical microscope. Debonding of the brazed surfaces was noticed, more pronounced toward the sleeve end which was exposed to uncontrolled atmospheric conditions intermittently. Initially, lack of wetting was suspected, presumably caused by inadequate surface preparation or incomplete fusion of the filler metal. However, this postulation was later discarded based upon the following observations: (1) The angle of wetting between the fillet and tube was small, an indication of adequate wetting, (2) the fillet did not exhibit a globular microstructure which would be an indication of insufficient melting of the filler metal, and (3) debonding was intermittent toward the midsection of the sleeve.


Author(s):  
Heinz Gross ◽  
Katarina Krusche ◽  
Peter Tittmann

Freeze-drying followed by heavy metal shadowing is a long established and straight forward approach to routinely study the structure of dehydrated macromolecules. Very thin specimens such as isolated membranes or single macromolecules are directly adsorbed on C-coated grids. After rapid freezing the grids are transferred into a suitable vacuum equipment for freeze-drying and heavy metal shadowing.To improve the resolution power of shadowing films we introduced shadowing at very low specimen temperature (−250°C). To routinely do that without the danger of contamination we developed in collaboration with Balzers an UHV (p≤10-9 mbar) machine (BAF500K, Fig.2). It should be mentioned here that at −250°C the specimen surface acts as effective cryopump for practically all impinging residual gas molecules from the residual gas atmosphere.Common high resolution shadowing films (Pt/C, Ta/W) have to be protected from alterations due to air contact by a relatively thick C-backing layer, when transferred via atmospheric conditions into the TEM. Such an additional C-coat contributes disturbingly to the contrast at high resolution.


2014 ◽  
Vol 56 ◽  
pp. 207-219 ◽  
Author(s):  
Chi L.L. Pham ◽  
Ann H. Kwan ◽  
Margaret Sunde

Amyloids are insoluble fibrillar protein deposits with an underlying cross-β structure initially discovered in the context of human diseases. However, it is now clear that the same fibrillar structure is used by many organisms, from bacteria to humans, in order to achieve a diverse range of biological functions. These functions include structure and protection (e.g. curli and chorion proteins, and insect and spider silk proteins), aiding interface transitions and cell–cell recognition (e.g. chaplins, rodlins and hydrophobins), protein control and storage (e.g. Microcin E492, modulins and PMEL), and epigenetic inheritance and memory [e.g. Sup35, Ure2p, HET-s and CPEB (cytoplasmic polyadenylation element-binding protein)]. As more examples of functional amyloid come to light, the list of roles associated with functional amyloids has continued to expand. More recently, amyloids have also been implicated in signal transduction [e.g. RIP1/RIP3 (receptor-interacting protein)] and perhaps in host defence [e.g. aDrs (anionic dermaseptin) peptide]. The present chapter discusses in detail functional amyloids that are used in Nature by micro-organisms, non-mammalian animals and mammals, including the biological roles that they play, their molecular composition and how they assemble, as well as the coping strategies that organisms have evolved to avoid the potential toxicity of functional amyloid.


2018 ◽  
Author(s):  
Peter V. Jones ◽  
Keith C. Sidwell

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