"光合作用"复习教学

“光合作用”教学内容的复习,要充分体现高考以基础知识为载体、以能力立意的命题指导思想。以构建知识体系、实验设计与探究、典型例题和实践应用为主线,全面培养学生的理解能力、推理能力、设计和完成实验能力、获取知识能力、分析综合能力。     

基于“做科学＂活动体验的概念教学——以“生物体的基本结构——细胞”的教学为例

以“生物体的基本结构——细胞”为例．论述初中阶段基于“做科学”活动的有效概念教学。教师在备课时可以借助思维导图,明确知识体系,找到“做科学”活动的最佳契合点,然后进行合理的安排,确定“做科学”活动的最佳安排,活动之后引领学生建构思维导图,对“做科学”活动进行最佳的收关。     

浅谈生物教学中如何使用“导”和“动”

“导”和“动”教学策略,是指教师以导情、导察、导思、导议、导行带动学生的动情、动眼、动脑、动口、动手。 1．导情与动情 导情即创设情景。新课之前,教师通过创设情景,如以扣人心弦的故事、逼真的教具、形象的语言等来引导学生,刺激学生大脑兴奋点,在极短的时间内,让学生注意力高度集中,以饱满的热情投入课堂活动之中。     

"生殖"一节课的教学感想

受千百年来封建意识的影响,导致“生殖”这节课的教学活动难于顺其自然地开展。实际教学中,教师启而不发、导而不动;学生不敢积极参与进来,大有回避之心。于是有的老师采取男女生分班上课,或者男教师给男生上,女教师给女生上,也有的教师干脆把本节课变为自读课——学生找时间课下自己看。笔者认为,教师采取这样的措施会在学生的心理上有暗示——“生殖”与“黄”联系起来。与其说含糊其辞地遮遮掩掩,还不如大大方方地把这节内容原原本本地传授给学生。本节课除了让学生理解生殖的概念,了解男女生殖系统的结构和功能、精子和卵细胞…     

利用综合图解形象化教学"鲫鱼"一节

初中阶段是学生从形象思维向抽象思维过渡的阶段。因此,在教学过程中应特别注意运用形象化教学手段,以促进学生对课本知识的理解与记忆。例如,我在讲授初中《生物》中的“鱼纲”内容时,首先让学生观察实物,然后再让学生结合插图预习课文。我在辅导学生预习课文的过程中发现,学生只是对鲫鱼的形态结构及循环过程有所了解,但是对鲫鱼的各器官、系统之间的相互关系很难理解。因此,我便根据课文中的插图对鲫鱼的“结构和生理”这一内容,运用边讲解边画综合图解的方法进行教学(如图)。鲫鱼的循环、呼吸、消化、排泄相互关系图解　　通过画图讲解,…     

“学导式”教学法在植物生理实验课教学中的应用

“学导式”教学主张“学为主体,导为主线”。“学为主体”一是指学生是教学的主体,二是肯定“学”在教学关系中的主体地位。“导为主线”是指教师在教学过程中变授为导,导贯穿教学全过程。从９０年代开始,我们将“学导式”教学法引入植物生理实验课的三大环节,即课前...     

生物教学的“六导”

生物教学的“六导”张品根（湖南省临湘桃矿中学４１４３１２）正确处理主导与主体的关系，提高课堂教学效果，关键在于教师的“导”。导如得法，则事半功倍。导什么？怎样导？我的做法是：１科学引入—一指导看课题的引入不但要让学生明白将要学什么，还要让学生明了为什...     

"神经调节"备考复习随想

以“神经调节”单元的备考复习为例,探讨高三生物学的系统复习阶段,教师应如何确定单元复习目标,重组单元课题内容和设计单元复习方案,从而将培养学生科学素养的理念落到实处。     

"有氧呼吸"的探究式教学

现代教育理论认为 ,学习科学的中心环节是探究。科学教学必须让学生参与以探究为目的的研究活动 ,使他们同老师和同学一起互相启发、互相促进。在美国BSCS生物学教材中 ,“有氧呼吸”单元课题的教学目标是 :能够自制热量测定仪装置 ;安全地独立完成“食物热价”测定的实验操作、数据整理和结果分析 ,用实验数据说明食物中含有能量 ;用简图说明有氧呼吸过程的主要阶段以及每个阶段中物质和能量的变化 ;说明运动与能量的关系 ,并利用所学知识指导自己的饮食健康。为了达到上述教学目标 ,我在“有氧呼吸”的教学过程中 ,主要采用实验探究 -课…     

"蝗虫"和"蜜蜂"两节教学设计

1　教学设计形式师生共同维持网站——“昆虫的世界”。2　教学设计依据现代教学与传统教学相比 ,师生在教学中的角色发生了根本性的转变 ,要求学生通过协作化学习、主动学习 ,掌握的是获取知识的过程、方法和途径。教师在课堂上充当的是组织者、管理者 ,是学生的学习伙伴 ,也就是要从以前“带领学生学”转变为“引导学生学”。3　教学设计意图3.1　教学内容分析　针对初一动物学中“节肢动物”一章里“蝗虫”和“蜜蜂”两节内容而设计的。教学大纲要求学生通过学习蝗虫、蜜蜂的知识 ,了解昆虫纲的主要特征、昆虫的发育及昆虫与人类的关系等…     

Genetico-demographic patterns of the prevalence of various forms of endogenous psychoses

Prevalence rates (PRs) for EFP (schizophrenic, schizoaffective and affective psychoses), with allowance for proband sex and age-of-onset data were studied in a subdivided population from the North-East of the European Region of the USSR. The population includes three subpopulations: a small old religious semi-isolate of Russians ("Rs"), aboriginal Komi people ("Ks")--an ethnic community of Ugro-Finnish lineage, and a mixed group of migrants ("Ms") from various regions of the USSR. The latter is mainly an urban population, while the "Rs" and "Ks" are, on the whole, rural populations. The total PR for EFP was found to be 0.97% for the "Rs", 0.63% for the "Ks" and 0.35% for the "Ms", whereas PRs-0.85-1.15% in other parts of the USSR, mainly for "panmixed" populations in large towns. The lower PRs for EFP in the "Ms" is caused by a backmigration flow involving certain groups of patients; consequently, the mean liability for "Ms" offsprings (as a whole) should also be lower. On the other hand, the lower PRs for EFP in the "Ks" is caused by underpresentation of clinically mild cases of the mental disease (mainly, pseudoneurotic schizophrenia), especially among female patients, probably due to that the so affected persons are sufficiently adapted to the cultural traditions of this rural population. It was shown that in the "Rs" the total PR for "nuclear" and paranoid schizophrenia is 0.68% versus 0.25% in a "panmixed" population. The increase is most likely caused by the high inbreeding level in the "Rs" semi-isolate, and if this is correct, we may suppose that at least one or two recessive genes are involved in the liability to the most heavy forms of schizophrenia. On the other hand, in the "Ms" (as in other "panmixed" populations) positive assortative mating among hereditary-predisposed persons is a more significant factor influencing family transmission of EFP, since the correlation between probands and their spouses is rpp = 0.31 (p less than 0.001) in the "Ms", as compared to rpp = 0.19 (p less than 0.1) in the "Rs". Thus, our general conclusion is that neither the place of inhabitance nor the life mode are the causal factors for EFP, but rather some genetic factors, more accurately, certain sets of specific genes.     

蕲州地区的蕲艾、青蒿、黄花蒿与茵陈的考订

<正> 蕲州是我国中药材主要产地之一,是湖北省蕲春县的一个集镇,,是我国中医药大师李时珍的家乡。该地区生长的菊科蒿属植物Artemisia Linn。颇多,其中入药的有十余种,并在李时珍《本草纲目》中曾有记载。这里仅对该地区常见入药的蕲艾、青蒿、黄花蒿与茵陈结合《本草纲目》记载的材料作初步的考订。     

Improved protein-ligand docking using GOLD

The Chemscore function was implemented as a scoring function for the protein-ligand docking program GOLD, and its performance compared to the original Goldscore function and two consensus docking protocols, "Goldscore-CS" and "Chemscore-GS," in terms of docking accuracy, prediction of binding affinities, and speed. In the "Goldscore-CS" protocol, dockings produced with the Goldscore function are scored and ranked with the Chemscore function; in the "Chemscore-GS" protocol, dockings produced with the Chemscore function are scored and ranked with the Goldscore function. Comparisons were made for a "clean" set of 224 protein-ligand complexes, and for two subsets of this set, one for which the ligands are "drug-like," the other for which they are "fragment-like." For "drug-like" and "fragment-like" ligands, the docking accuracies obtained with Chemscore and Goldscore functions are similar. For larger ligands, Goldscore gives superior results. Docking with the Chemscore function is up to three times faster than docking with the Goldscore function. Both combined docking protocols give significant improvements in docking accuracy over the use of the Goldscore or Chemscore function alone. "Goldscore-CS" gives success rates of up to 81% (top-ranked GOLD solution within 2.0 A of the experimental binding mode) for the "clean list," but at the cost of long search times. For most virtual screening applications, "Chemscore-GS" seems optimal; search settings that give docking speeds of around 0.25-1.3 min/compound have success rates of about 78% for "drug-like" compounds and 85% for "fragment-like" compounds. In terms of producing binding energy estimates, the Goldscore function appears to perform better than the Chemscore function and the two consensus protocols, particularly for faster search settings. Even at docking speeds of around 1-2 min/compound, the Goldscore function predicts binding energies with a standard deviation of approximately 10.5 kJ/mol.     

Asymmetries in population growth regulated by intraspecific competition: Empirical studies and model tests

Summary The linearity assumption in the logistic model of population growth is violated for nearly all organisms. Two simple models, the -logistic and the -Ricker, are shown to account for asymmetric patterns of population growth for 27 species of Drosophila and for a variety of other organisms, where the data were derived from the literature. These models are developed so as to aid laboratory and field ecologists to anticipate the dynamics of various experimental organisms. Potential problems of data gathering and model applications for experimental ecologists and wild life management biologists are identified. Intraspecific asymmetries offer alternative explanations to the habitat selection model, and the higher order interactions or coalitions model, for interspecific competition.     

Source-sink landscape theory and its ecological significance

Exploring the relatiouships between landscape pattern and ecological processes is the key topic of landscape ecology,for which,a large number of indices as well as landscape pattern analysis model were developed.However,one problem faced by landscape ecologists is that it is hard to link the landscape indices with a specific ecological process.Linking landscape pattern and ecological processes has become a challenge for landscape ecologists."Source" and "sink" are common concepts used in air pollution research,by which the movement direction and pattern of different pollutants in air can be clearly identified.In fact,for any ecological process,the research can be considered as a balance between the source and the sink in space.Thus,the concepts of "source" and "sink" could be implemented to the research of landscape pattern and ecological processes.In this paper,a theory of sourcesink landscape was proposed,which include:(1) In the research of landscape pattern and ecological process,all landscape types can be divided into two groups,"source"landscape and "sink" landscape."Source" landscape contributes positively to the ecological process,while "sink" landscape is unhelpful to the ecological process.(2) Both landscapes are recognized with regard to the specific ecological process."Source" landscape in a target ecological process may change into a "sink"landscape as in another ecological process.Therefore,the ecological process should be determined before "source"or "sink" landscape were defined.(3) The key point to distinguish "source" landscape from "sink" landscape is to quantify the effect of landscape on ecological process.The positive effect is made by "source" landscape,and the negative effect by "sink" landscape.(4) For the same ecological process,the contribution of "source" landscapes may vary,and it is the same to the "sink"landscapes.It is required to determine the weight of each landscape type on ecological processes.(5) The sourcesink principle can be applied to non-point source pollution control,biologic diversity protection,urban heat island effect mitigation,etc.However,the landscape evaluation models need to be calibrated respectively,because different ecological processes correspond with different source-sink landscapes and evaluation models for the different study areas.This theory is helpful to further study landscape pattern and ecological process,and offers a basis for new landscape index design.     

Topology and Growth of the Intracytoplasmic Membrane System of Rhodopseudomonas spheroides: Protein, Chlorophyll, and Phospholipid Insertion into Steady-State Anaerobic Cells

An equilibrium density gradient centrifugation study involving the separation of "old" and "new" membranes has been developed to determine the manner in which protein, lipid, and chlorophyll are incorporated into growing intracytoplasmic membranes (chromatophores) of Rhodopseudomonas spheroides. Chromatophores derived from cells grown in an H(2)O-medium had a density of 1.175 to 1.180 g/cm(3) and were readily separable from chromatophores having a density of 1.220 to 1.230 isolated from cells grown in a 70% D(2)O-medium. After a shift from "D(2)O-" to "H(2)O"-based media, only hybrid chromatophores derived from a combination of "heavy" (old) and "light" (new) chromatophore material could be detected. The experimentally determined, median density values for the growing intracytoplasmic membrane system followed a theoretically determined profile which was calculated from the density of full "heavy" and full "light" material assuming random, homogeneous incorporation of new material into old membrane. The distribution of the radioactive labels for protein (leucine) and chlorophyll (delta-aminolevulinic acid) were identical and showed a reproducible displacement of the "old" material to the heavy side of the optical density at 365 nm (OD(365)) absorbance and a displacement of the "new" material to the light side of the OD(365) absorbance profile. Specific phospholipid growth showed no displacement for either the "old" or "new" material from the median absorbance profile.     

Extent of heterosis in rice (Oryza sativa L.) under cold stress conditions — yield and its components

Summary The nature and extent of heterosis for grain yield and its component characters was estimated in a seven-parent F₁-diallel cross in rice under the cold stress conditions of Palampur, representing sub-temperate climate of the mid hills of Himachal Pradesh. The highest heterotic effects for grain yield were observed in Himalaya 1/Phul Patas 72 and China 988/Himdhan hybrids, which gave 60.36 and 32.48% heterosis, respectively, over mid parent, 38.76 and 26.86% heterosis, respectively, over high parent and 32.30 and 26.86% heterosis, respectively, over the best variety, Himdhan. Heterosis for grain yield in these crosses was due to an increase in tiller number, panicle length, spikelets/panicle and 1,000-grain weight. Large number of crosses exhibited significant heterosis for high spikelet sterility and the majority of them had significant heterosis for late flowering, taking more than 120 days to flower, which resulted in lack of heterosis for grain yield in such crosses due to cold stress at the reproductive stage.Part of the thesis submitted by the senior author to Himachal Pradesh Agricultural University, Palampur (H.P.) India, in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Agriculture     

Inhibition of the Myotoxicity Induced by Bothrops jararacussu Venom and Isolated Phospholipases A2 by Specific Camelid Single-Domain Antibody Fragments

Antivenoms, produced using animal hyperimmune plasma, remains the standard therapy for snakebites. Although effective against systemic damages, conventional antivenoms have limited efficacy against local tissue damage. Additionally, the hypersensitivity reactions, often elicited by antivenoms, the high costs for animal maintenance, the difficulty of producing homogeneous lots, and the instability of biological products instigate the search for innovative products for antivenom therapy. In this study, camelid antibody fragments (VHH) with specificity to Bothropstoxin I and II (BthTX-I and BthTX-II), two myotoxic phospholipases from Bothrops jararacussu venom, were selected from an immune VHH phage display library. After biopanning, 28 and 6 clones recognized BthTX-I and BthTX-II by ELISA, respectively. Complementarity determining regions (CDRs) and immunoglobulin frameworks (FRs) of 13 VHH-deduced amino acid sequences were identified, as well as the camelid hallmark amino acid substitutions in FR2. Three VHH clones ({"type":"entrez-nucleotide","attrs":{"text":"KF498607","term_id":"558064687"}}KF498607, {"type":"entrez-nucleotide","attrs":{"text":"KF498608","term_id":"558064693"}}KF498608, and {"type":"entrez-nucleotide","attrs":{"text":"KC329718","term_id":"468362338"}}KC329718) were capable of recognizing BthTX-I by Western blot and showed affinity constants in the nanomolar range against both toxins. VHHs inhibited the BthTX-II phospholipase A₂ activity, and when tested for cross-reactivity, presented specificity to the Bothrops genus in ELISA. Furthermore, two clones ({"type":"entrez-nucleotide","attrs":{"text":"KC329718","term_id":"468362338"}}KC329718 and {"type":"entrez-nucleotide","attrs":{"text":"KF498607","term_id":"558064687"}}KF498607) neutralized the myotoxic effects induced by B. jararacussu venom, BthTX-I, BthTX-II, and by a myotoxin from Bothrops brazili venom (MTX-I) in mice. Molecular docking revealed that VHH CDRs are expected to bind the C-terminal of both toxins, essential for myotoxic activity, and to epitopes in the BthTX-II enzymatic cleft. Identified VHHs could be a biotechnological tool to improve the treatment for snake envenomation, an important and neglected world public health problem.     

用《组合中药学》的理论开发新型中药

我们以现代科技理论为出发点,提出了<组合中药学>新理论体系,试图使中外学者对中药的认识趋于一致.中药的本质就是"组合".无论是单方或复方都是一个庞大的分子库.具有相同或相似功能的分子组合成一个群体.这些群体表现出特定的药效."组合"有三层意思生药的组合、活性分子群的组合与特定疗效的组合.分子群是特定药效功能的物质基础.<组合中药学>就是从<组合分子>水平上研究中药及其药效的物质基础,阐明中药活性部位的相互作用与药效的相互关系及其作用机制.<组合中药学>的三个新概念中药功效分子族具有相似药效作用的一类分子的组合,其骨架及功能团相同或相似.单味中药表征性组合分子单味中药药效的代表性功效分子族,即主要药效分子组合.单味中药非表性组合分子单味中药表征性分子以外的其它功效分子族,即辅助药效分子的组合.<组合中药学>的主要研究范围中药药效的组合分子学基础(植物化学,天然产物);组合分子的药理学基础(分子生物学,细胞生物学,药理学).本文提出了应用<组合中药学>研究新型中药的新方法.     

Is there anything "autonomous" in the nervous system?

The terms "autonomous" or "vegetative" are currently used to identify one part of the nervous system composed of sympathetic, parasympathetic, and gastrointestinal divisions. However, the concepts that are under the literal meaning of these words can lead to misconceptions about the actual nervous organization. Some clear-cut examples indicate that no element shows "autonomy" in an integrated body. Nor are they solely "passive" or generated "without mental elaboration." In addition, to be "not consciously controlled" is not a unique attribute of these components. Another term that could be proposed is "homeostatic nervous system" for providing conditions to the execution of behaviors and maintenance of the internal milieu within normal ranges. But, not all homeostatic conditions are under the direct influence of these groups of neurons, and some situations clearly impose different ranges for some variables that are adaptative (or hazardous) in the tentative of successfully coping with challenging situations. Finally, the name "nervous system for visceral control" emerges as another possibility. Unfortunately, it is not only "viscera" that represent end targets for this specific innervation. Therefore, it is commented that no quite adequate term for the sympathetic, parasympathetic, and gastrointestinal divisions has already been coined. The basic condition for a new term is that it should clearly imply the whole integrated and collaborative functions that the components have in an indivisible organism, including the neuroendocrine, immunological, and respiratory systems. Until that, we can call these parts simply by their own names and avoid terms that are more "convenient" than appropriate.