An Examination of Students' understanding of some Principles of Scientific Methods

Sources of Biological Films

Firms which Supply Films

Films for Universities. Pp. 292. British Universities Film Council, London, 1968. 35s.     

Mathematics and School Biology

A model, based on commercially available beads, is described. The model enables many of the biochemical and chromosomal processes involved in the transmission of the genetic material to be easily and cheaply illustrated.     

A Modern Biology Syllabus at O-level

The biotic indexing of water quality and its application to A-level field work is discussed with reference to the Trent Biotic Index and Chandler Score system. These indices are related to the classification of water quality used by the Department of the Environment in the River Pollution surveys of 1970 and 1975.

The interpretation of these indices is also considered and their limitations are discussed.     

A teaching exercise for the identification of bacteria using an interactive computer program

An interactive computer program written in Fortran is described which provides an exercise in the identification of bacteria. The program, IDEN, provides a novel way of enhancing a student's approach to systematic bacteriology and numerical identification procedures. An unknown bacterium is assigned to a student who is provided with a list of possible species and a list of tests which may be carried out. The student's objective is the correct identification of the unknown in the most economical manner. An indication is given concerning the way in which this program can be used to enhance theoretical instruction and practical investigation.     

Science out of the classroom

A recent survey estimates that 65% of secondary-age school children (11–16 years) in the UK have access tothe Internet at home.Most pupils are, therefore, already learning through information and communicationtechnology (ICT). Butthere are still questions about how ICT is being used for teaching science in schoolswithin the UK.     

Characterisation of Digestive Enzymes in Freshly Killed Animals

We present an investigation (for A-level biology students and equivalent) into the mechanism of glucose-induced extracellular acidification in unbuffered yeast suspensions. The investigation is designed to enhance understanding of aspects of the A-level curriculum that relate to the phenomenon (notably glucose catabolism) and to develop key skills in scientific enquiry.We demonstrate that glucose-induced extracellular acidification (monitored by pH electrodes linked to a computer) is inhibited by glycolytic and TCA cycle inhibitors. Dimethylsuccinate, which forms succinate after entering cells, also induces acidification that is inhibited by malonate, an inhibitor of succinate oxidation. The yeast plasma membrane has a proton pump that extrudes protons from the cell. However, inhibitors of the pump do not affect glucose-induced acidification during 20 minutes of monitoring pH, indicating that under the experimental conditions employed, the pump does not have a significant role in the process. Taken together, the data indicate that glucose-induced acidification of the medium occurs as a result of its catabolism and subsequent outward diffusion of the CO₂ derived from respiration and/or fermentation. A discussion is presented on how the investigations developed skills of scientific enquiry in undergraduate trainee teachers who carried out some of the experiments and on how the investigations can be used to enhance these skills in A-level students.     

Biology-specific vocabulary: students’ understanding and lecturers’ expectations of student understanding

Abstract

The current A-level biology curriculum includes a broad coverage of all the biosciences which demands knowledge of a wide range of biological vocabulary. Students (n = 184) from two UK universities were presented with a list of vocabulary, associated with a ‘Revise Biology’ text which highlighted key terms that students should know. Lecturers (n = 26) were asked which of these terms they expected students to know, or be aware of. Findings revealed that students’ claimed knowledge of vocabulary exceeded lecturer expectations. In addition, there were a number of terms which students did not understand and lecturers did not expect them to know, which could be removed from A-level biology courses. This is discussed in relation to whether A-level curricula need to be so content heavy and whether lecturers would benefit from knowing more about their students’ knowledge of discipline-specific terms.     

Formative fieldwork: the age of the sixth form course

Two hundred and fifty-eight thousand A-level students have attended one-week field courses at Field Studies Council Residential Centres during the past 30 years. Biology courses have had a strongly ecological basis throughout, with an emphasis on the study of the whole environment. Only in recent years have financial constraints forced the organization to restructure academically-desirable programmes in favour of overtly syllabus-orientated curricula. There have, however, been but trivial changes in the pattern of work. The emphasis of the field course is based firmly on the students' own field and laboratory observations. Staff are facilitators not dictators.     

The pressure-flow hypothesisof phloem transport: misconceptions in the A-level textbooks

Schoolteachers perceive the pressure-flow hypothesis as difficult to teach. A look at some textbooks in use inthe sixth-form classroom gives the reason why. This article criticises the treatment given to the pressure-flow hypothesis by nine textbooks while showing how this model for long-distance sugar movement in plants canbe explained simply and effectively. Questions of a wider, educational nature are raised.     

fungi4schools - the new BMS education website

The one place it's almost impossible to find fungi is in the UK National Curriculum for schools. The state of the National Curriculum (NC) is a real concern because the current specifications all contain material on animal and plant comparisons with little or no consideration for the largest group of higher organisms on Earth: Kingdom Fungi. This means that children are missing out on being taught about the importance of an entire Kingdom of higher organisms. To try to compensate for this educational deficiency, the British Mycological Society has taken up the challenge by devising resources teachers can use within the current NC because they address NC topics and also give proper representation to fungi. These resources include specially-produced and ready-to-use lessons and classroom activities, teacher's guides and pupil class sheets, all classroom tested and well received by pupils. But the resources also feature articles published over many years in the Society's journals that need to be brought out of the library archives and made immediately accessible to schools. These resources are available now for free download from the British Mycological Society's new education website at www.fungi4schools.org, which is described in this article.     

The study of neighboring nucleotide composition and transition/transversion bias

Base substitution is one of the raw fuels that produce genetic variation and drive evolution. Recent studies have shown that the genome components affect mutation patterns to some extent. In order to infer the correlation between the Transition/Transversion ratio (Ts/Tv) and the number of immediately adjacent A&T nucleotides, we investigated 3611007 Oryza sativa SNPs (including 45462 coding SNPs, and 242811 intronic SNPs) and 32019 Arabidopsis SNPs. The results show that Ts/Tv is negatively correlated with the number of immediately adjacent A&T in O. Sativa and Arabidopsis. We further calculated AT₂ (the number of SNPs whose immediately adjacent nucleotides are either A or T) and AT₀ (the number of SNPs whose immediately adjacent nucleotides are either C or G) for all 6 types of SNPs. C/G SNP of O. sativa and Arabidopsis has the highest AT₂/AT₀, which denotes C/G SNP may be influenced by the adjacent A&T nucleotides mostly. For SNPs in O. sativa, the neighboring effect of A&T nucleotides is limited to 2 nucleotides on both sides; for SNPs in Arabidopsis, the effect extends no more than 4 nucleotides on both sides.     

Transition from paediatric to adult care of adolescent patients with congenital heart disease: a pathway to optimal care

Introduction

Adolescents with congenital heart disease transition from a paediatric to an adult setting. This is associated with loss-to-follow-up and suboptimal care. Increasing numbers of patients justify a special program. In this study we evaluated the cooperative program between paediatric and adult cardiology departments in a tertiary referral centre.

Methods

In this retrospective study, patients with congenital heart disease with at least one appointment scheduled at the transition program between January 2010 and January 2015 were included. They were seen by a paediatric cardiologist at the age of 15 years in the paediatric department and from age 18 to 25 in the adult department. Demographic and medical data were collected from the electronic patient files.

Results

A total of 193 patients (105 males, 88 females) were identified. Sex distribution was almost equal. Most patients were 18–21 years of age. The largest group, 128 patients (67?%), lived within 50 kilometres of our hospital. Paediatric cardiologists referred 157 (81?%) of patients. General practitioners and cardiologists from outside our centre were important referrers for patients lost to follow-up, together accounting for 9?%. A total of 34 (18?%) patients missed an appointment without notification. Repeat offenders, 16 of 34 patients, formed a significant minority within this group. A total of 114 (59?%) patients were attending school, 46 (24?%) were employed, and 33 (17?%) patients were inactive. Activities are in line with capabilities. A nurse practitioner was involved with the 7?% with complex and psychosocial problems. Moderately severe congenital heart defects formed the largest patient category of 102 (53?%) patients. In 3?% of patients the diagnosis had to be revised or was significantly incomplete. In 30 (16?%) patients, cardiac diagnosis was part of a syndrome. Of the 193 patients, 117 (92?%) were in NYHA class I, with 12 (6?%) and 4 (2?%) patients falling into classes II and III, respectively.

Conclusions

A viable transition program can be built by collaboration between paediatric and adult cardiology departments with the same treating physician taking care of patients between 15 and 25 years of age. General practitioners are important in returning lost-to-follow-up patients to specialised care. Nurse practitioners are essential in the care for patients with complex congenital heart disease.

     

The reaction force and the transition region of a reaction

The reaction force F(R) and the position-dependent reaction force constant κF(R) are defined by F(R)=-∂V(R)/∂R and κ(R)=∂²V(R)/∂R², where V(R) is the potential energy of a reacting system along a coordinate R. The minima and maxima of F(R) provide a natural division of the process into several regions. Those in which F(R) is increasing are where the most dramatic changes in electronic properties take place, and where the system goes from activated reactants (at the force minimum) to activated products (at the force maximum). κ(R) is negative throughout such a region. We summarize evidence supporting the idea that a reaction should be viewed as going through a transition region rather than through a single point transition state. A similar conclusion has come out of transition state spectroscopy. We describe this region as a chemically-active, or electronically-intensive, stage of the reaction, while the ones that precede and follow it are structurally-intensive. Finally, we briefly address the time dependence of the reaction force and the reaction force constant.     

Wilkes Land Late Pleistocene diatom age model: From bio-events to quantitative biostratigraphy

A new method merges conventional and quantitative biostratigraphic approaches, supported by magnetic polarity data, to develop a chronological framework for sediment core MD03-2595 retrieved on the continental rise off Wilkes Land, East Antarctica before proceeding to paleoceanographic and paleoclimatic analysis. This combined method helped to identify climatic cycles, highlight stratigraphic discontinuities and reworking, and assess regional sedimentological and diatom biostratigraphic evolution. Core MD03-2595 spans the last 0.8 Ma, from the Mid Pleistocene Transition (MPT) to the Early Holocene. A hiatus including Marine Isotope Stages (MIS) 19, 18 and 17 was identified, and a decreasing trend in sediment accumulation rates from MIS 16 to the Holocene was observed. This quantitative diatom biostratigraphic dataset, placed in its own sedimentological and paleomagnetic context, provides new information regarding the paleobiogeographic distribution and ecological responses of biostratigraphically significant diatom species, such as Thalassiosira elliptipora and T. fasciculata, for the Matuyama–Brunhes (M–B) transition, and Actinocyclus ingens, Hemidiscus karstenii and Rouxia spp. for the middle and late Pleistocene diatom biozonation.     

Synthesis, crystal structure, hydrogen bonding and spectroscopy of Co, Mn and Ni oxalate complexes with the ligand (N,N′-bis(2-pyridylmethyl)-1,3-propanediamine)

Three new compounds are reported with the tetradentate ligand (N,N′-bis(2-Pyridylmethyl)-1,3-propanediamine) (abbreviated as pypn), two mononuclear compounds i.e. [Co(pypn)(C₂O₄)](ClO₄) (1), [Mn(pypn)(C₂O₄)](ClO₄) (2) and one dinuclear compound [Ni₂(pypn)₂(C₂O₄)](ClO₄)₂(C₂H₆O)_1/4(H₂O) (3). In the Co(III) and Mn(II) complexes the oxalate behaves as bidentate ligand, chelating the metal in the O,O′ mode, whereas in the Ni(II) compound the oxalate behaves as tetradentate ligand binding each Ni(II) ion by two oxygen atoms and bridging the two metallic centers.The synthesis, X-ray crystal structure of all three compounds and their spectroscopic properties are presented in detail. The geometry around the Co³⁺, Mn³⁺, Ni²⁺ ions is essentially octahedrally based, while the stabilization of the crystal lattice in all cases is maintained by interesting hydrogen bond systems.     

Distribution of transition metal ions in multiple forms of Methanosarcina hydrogenase

There were significant levels of in vitro hydrogenase activity in Methanosarcina strains. The multiple forms of hydrogenase were observed in cell free extracts of cells grown on methanol. Strains having poor growth on H₂ : CO₂ had four forms while strains having normal growth on all substrates contained two forms of hydrogenase. These multiple forms differ in their charges as well as in their composition of transition metal ions. The strain having normal growth showed higher incorporation of ⁶³Ni²⁺ and ⁶⁵Zn²⁺. Both hydrogenases, A and D, of strain P₃ had methylviologen and F₄₂₀-reducing activity and contained Zn²⁺ and Co²⁺ respectively. Hydrogenases A and D of strains P₁ and P₄ also had similar characteristics whereas hydrogenases B and C had only methylviologen reducing activity.     

Correlative variations of the free energies for enzyme-substrate complex formation and the transition-state stabilization for RNases

It was found for RNases of different specificities that changes in the free energy for substrate-enzyme binding induced by variations in the nucleotide base structure are accompanied by proportional changes in kcat/Km. This was considered to be a consequence of the strain in the enzyme-substrate complex.     

《遗传学》教学中若干问题的数学解析Ⅱ

遗传学教学过程中会发现一系列启发性的问题,涉及孟德尔遗传、数量遗传、群体遗传和人类遗传等领域,这些问题对许多学生来讲有趣且有一定难度。收集了若干启发性问题,包括自交后代各种表型可能出现的频率、多次回交的目的、显性性状是否在群体中占有更大的比例、为什么母亲的年龄与子女的正常与否有很大的关系、遗传力的估算方法等,并用数学方法一一进行剖析,以供相关同学和同行借鉴和思考。