scholarly journals Student conceptions about energy transformations: progression from general chemistry to biochemistry

2014 ◽  
Vol 15 (2) ◽  
pp. 168-183 ◽  
Author(s):  
Adele J. Wolfson ◽  
Susan L. Rowland ◽  
Gwendolyn A. Lawrie ◽  
Anthony H. Wright
Keyword(s):  
General Chemistry ◽  
Free Energy ◽  
Reaction Pathway ◽  
Second Law Of Thermodynamics ◽  
Alternative Conceptions ◽  
Tertiary Institution ◽  
Biological Reaction ◽  
Closed Systems ◽  
Depth Interviews ◽  
Standard Energy

Students commencing studies in biochemistry must transfer and build on concepts they learned in chemistry and biology classes. It is well established, however, that students have difficulties in transferring critical concepts from general chemistry courses; one key concept is “energy.” Most previous work on students' conception of energy has focused on their understanding of energy in the context of physics (including the idea of “work”) and/or their understanding of energy in classical physical and inorganic chemistry contexts (particularly Gibbs Free Energy changes, the second law of thermodynamics, and equilibrium under standard conditions within a closed system). For biochemistry, students must go beyond those basic thermodynamics concepts of work, standard energy changes, and closed systems, and instead they must consider what energy flow, use, and transformation mean in living, open, and dynamic systems. In this study we explored students' concepts about free energy and flow in biological chemical reactions and metabolic pathways by surveys and in-depth interviews. We worked with students in general chemistry classes and biochemistry courses in both an Australian and a US tertiary institution. We address three primary questions (i) What are the most common alternative conceptions held by students when they explain energy-related phenomena in biochemistry?, (ii) What information do students transfer from introductory chemistry and biology when they are asked to consider energy in a biological reaction or reaction pathway?, and (iii) How do students at varying levels of competence articulate their understandings of energy in pathways and biological reactions? The answers to these questions are used to build a preliminary learning progression for understanding “energy” in biochemistry. We also propose crucial elements of content knowledge that instructors could apply to help students better grasp this threshold concept in biochemistry.

Barriers to Female Condom Use among Undergraduate Health Science Students

2020 ◽  
Vol 22 (1) ◽  
Author(s):  
Bongekile T. Dlamini ◽  
Mduduzi Colani Shongwe
Keyword(s):  
Undergraduate Students ◽  
Female Condom ◽  
Sexual Pleasure ◽  
Health Science ◽  
Science Students ◽  
Tertiary Institution ◽  
Health Science Students ◽  
Inadequate Knowledge ◽  
Interview Guide ◽  
Depth Interviews

The female condom (FC), also known as the femidom, has been on the market since 1993, however, its use remains limited in many parts of southern Africa, including in Eswatini (formerly Swaziland). There is a dearth of literature on the reasons for the limited use of the FC, especially from the perspective of health science students who would otherwise be expected to be knowledgeable about and have favourable attitudes to it. The aim of this study was to explore and describe the barriers to FC use among undergraduate health science students at a selected tertiary institution in Eswatini. A qualitative, exploratory descriptive study was conducted among nine conveniently sampled, unmarried undergraduate students at a selected tertiary institution in the Hhohho region in Mbabane, Eswatini. Responses to an unstructured interview guide, using in-depth interviews were analysed thematically following Creswell’s steps of qualitative data analysis. Five themes emerged from the data: (1) inadequate knowledge about the FC, (2) the FC hinders sexual pleasure, (3) insertion of the FC is time-consuming and uncomfortable, (4) the FC is bigger than the vagina, and (5) fear of being labelled “promiscuous”. Generally, the participants stated that they did not use the FC because of societal myths. Therefore, there is a need to strengthen health education campaigns for the femidom to clear the myths and misconceptions that limit its use.

First and second laws of thermodynamics: relationship, “inconsistency”, hidden effects

2020 ◽  
pp. 63-73
Author(s):  
A. M. Savchenko ◽  
Yu. V. Konovalov ◽  
A. V. Laushkin
Keyword(s):  
Free Energy ◽  
Internal Energy ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Entropy Of Mixing ◽  
Ideal Mixing ◽  
Laws Of Thermodynamics ◽  
Relationship Of ◽  
The Relationship

The relationship of the first and second laws of thermodynamics based on their energy nature is considered. It is noted that the processes described by the second law of thermodynamics often take place hidden within the system, which makes it difficult to detect them. Nevertheless, even with ideal mixing, an increase in the internal energy of the system occurs, numerically equal to an increase in free energy. The largest contribution to the change in the value of free energy is made by the entropy of mixing, which has energy significance. The entropy of mixing can do the job, which is confirmed in particular by osmotic processes.

scholarly journals A thermodynamic approach to rate-type models in deformable ferroelectrics

2020 ◽  
Author(s):  
Claudio Giorgi ◽  
Angelo Morro
Keyword(s):  
Free Energy ◽  
Electric Field ◽  
Second Law Of Thermodynamics ◽  
Second Law ◽  
Energy Models ◽  
Polarization Electric Field ◽  
Field Plane ◽  
Vector Valued ◽  
Rate Type ◽  
Hysteretic Properties

AbstractThe purpose of the paper is to establish vector-valued rate-type models for the hysteretic properties in deformable ferroelectrics within the framework of continuum thermodynamics. Unlike electroelasticity and piezoelectricity, in ferroelectricity both the polarization and the electric field are simultaneously independent variables so that the constitutive functions depend on both. This viewpoint is naturally related to the fact that an hysteresis loop is a closed curve in the polarization–electric field plane. For the sake of generality, the deformation of the material and the dependence on the temperature are allowed to occur. The constitutive functions are required to be consistent with the principle of objectivity and the second law of thermodynamics. Objectivity implies that the constitutive equations are form invariant within the set of Euclidean frames. Among other results, the second law requires a general property on the relation between the polarization and the electric field via a differential equation. This equation shows a dependence fully characterized by two quantities: the free energy and a function which is related to the dissipative character of the hysteresis. As a consequence, different hysteresis models may have the same free energy. Models compatible with thermodynamics are then determined by appropriate selections of the free energy and of the dissipative part. Correspondingly, major and minor hysteretic loops are plotted.

scholarly journals The Effect of the Protein Synthesis Entropy Reduction on the Cell Size Regulation and Division Size of Unicellular Organisms

Entropy ◽  
2022 ◽  
Vol 24 (1) ◽  
pp. 94
Author(s):  
Mohammad Razavi ◽  
Seyed Majid Saberi Fathi ◽  
Jack Adam Tuszynski
Keyword(s):  
Free Energy ◽  
Protein Synthesis ◽  
Cell Size ◽  
Cell Biology ◽  
Second Law Of Thermodynamics ◽  
Underlying Mechanism ◽  
Energy Balance Equation ◽  
Second Law ◽  
Entropy Reduction ◽  
Unicellular Organisms

The underlying mechanism determining the size of a particular cell is one of the fundamental unknowns in cell biology. Here, using a new approach that could be used for most of unicellular species, we show that the protein synthesis and cell size are interconnected biophysically and that protein synthesis may be the chief mechanism in establishing size limitations of unicellular organisms. This result is obtained based on the free energy balance equation of protein synthesis and the second law of thermodynamics. Our calculations show that protein synthesis involves a considerable amount of entropy reduction due to polymerization of amino acids depending on the cytoplasmic volume of the cell. The amount of entropy reduction will increase with cell growth and eventually makes the free energy variations of the protein synthesis positive (that is, forbidden thermodynamically). Within the limits of the second law of thermodynamics we propose a framework to estimate the optimal cell size at division.

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