“生物膜的流动镶嵌模型”单元式教学设计

构建6个主题单元：①变形虫告诉我们（导入）；②模型构建中的逻辑推理和实验观察；③实验技术进步对生物膜研究的作用；④模型构建中结构与功能的适应；⑤假说的提出和修正；⑥体验美和创造关（结尾），着力于知识的理解、创新精神和实践能力的培养以及情感的渗透。     

“生物膜的流动镶嵌模型”一节教学设计

在“生物膜的流动镶嵌模型”一节教学中,通过自主建构模型,学生在真实情境中分析关键问题,深度挖掘现象背后的本质规律,运用合理的科学方法解决实际问题。在教学过程中注重培养学生的高阶思维和解决真实情境问题的能力。     

“生物膜的流动镶嵌模型”一节整合科学史的教学设计

1教材分析 本节内容选自人教版高中生物学必修1《分子与细胞》第4章第2节。该节内容在编排上按时间顺序介绍了科学家对生物膜结构探索历程的一些重要实验和推论。旨在让学生一步一步地分析科学家的实验和结论。使学生宛如亲历科学家探索的历程，自然而然地接受流动镶嵌模型的理论，同时加深对科学过程与方法的理解。     

“生物膜的流动镶嵌模型”基于科学史的教学设计

利用生物膜研究的科学史资料,引导学生进行基于资料的课堂探究性学习,注重学生自主、合作、探究的学习方式,达成知识、能力、情感态度与价值观的三维目标。     

“生物膜的流动镶嵌模型”一节的难点突破

人教版必修1第4章第2节＂生物膜的流动镶嵌模型＂一节,其内容涉及的大多是一些＂探索生物膜结构＂的描述性实验,如果直接将这些实验告诉学生,比较枯燥、抽象,远离学生实际生活,学生缺少直观认识。因此,理解和接受起来有些难度,而且又会走上死记硬背的老路上来,体现不了新课改的理念。为解决这一问题,笔者在教学中采用了利用橡皮泥等建构模型以及和课件相结合的教学手段,取得了很好的教学效果。     

“生物膜的流动镶嵌模型”的教学设计

以科学实验资料为背景创设问题情境,引导学生自主构建生物膜模型和解释生物膜模型等活动,让学生在活动中理解知识的产生过程,形成科学概念,习得科学方法,培养科学精神。     

“生物膜的流动镶嵌模型”课堂教学主线设计浅析

笔者研读了新课改以来,同仁对“生物膜的流动镶嵌模型”一节的课堂教学研究成果,对不同的构思均颇有感触,从中提炼出了本节的3种教学主线：三维一体线、模型制作线、逆向思维线。3种教学主线的设计方法,都是属于新课改中热议的模型建构方法。其中前2种主线是顺势思维的模型建构,而第3种则是具有创意的逆向思维的模型建构,它们以不同的方式呈现和诠释着同一主题。3种设计各有优点,在教学过程中,教师可以根据教学实际情况．采用不同的教学主线,甚至可以将不同主线组合起来用。     

“生物膜的流动镶嵌模型”教学中若干问题的分析与处理

“生物膜的流动镶嵌模型”是非常好的科学史教学素材,但在教学中需要深刻理解和解读“暗－亮－暗”图像的含义,深层次地分析生物膜流动性的成因、蛋白质与磷脂双分子层的关系以及磷脂单分子层与水界面的相互作用,才能使知识教学更科学、思维更严密,更有利于学生科学素养的熏陶和培养。     

生物膜模型的提出及其演变过程

生物膜模型的提出及其演变过程孙颖（河北师范大学生物学系０５００１６）１９世纪末，细胞学家用光镜观察各种植物细胞和单细胞生物，并用物理及化学技术探测细胞边界时，逐渐意识到在细胞表面存在着一层显然有别于原生质性质的膜，因为这层膜有弹性，可伸展，不同于细胞...     

基于情境创设策略的“生物膜的流动镶嵌模型”教学设计

真实的情境,能增强学生对自然现象的好奇心和求知欲,培养学生的观察能力,促进学生感悟科学探究的基本方法。在"生物膜的流动镶嵌模型"的教学设计中,创设实验等真实的情境,促进学生在学习过程中提升生物学学科核心素养。     

“植株的生长”教学设计

初中生物学课程标准强调学生的主动学习,期望更好地发展学生的探究能力和解决问题能力.受此教学理念的影响,在"植株的生长"教学设计中,力求使用相关教学资源,在初一年级学生已初步具有设计对照实验能力的基础上,不断引导其主动思考,通过设计和分析一连串实验,或侧重发展作出假设、设计实验、预期结果的能力,或侧重发展分析结果、得出结论的能力,让学生运用科学的证据与逻辑,构建核心概念,并最终达到课标的要求.     

"人与生物圈"单元的整体教学设计

教材将本单元内容编排在必修课最后一部分讲述,既是“生物与环境”一章知识的自然延伸和提高,也是综合应用“代谢、生殖、发育、遗传”等知识理解和解决实际问题的充分体现．同时还是比较集中地阐述人的自然属性、人与自然必须协调发展的思想的一章。     

Lipid peroxidation modifies the picture of membranes from the "Fluid Mosaic Model" to the "Lipid Whisker Model"

The “Fluid Mosaic Model”, described by Singer and Nicolson, explain both how a cell membrane preserves a critical barrier function while it concomitantly facilitates rapid lateral diffusion of proteins and lipids within the planar membrane surface. However, the lipid components of biological plasma membranes are not regularly distributed. They are thought to contain “rafts” - nano-domains enriched in sphingolipids and cholesterol that are distinct from surrounding membranes of unsaturated phospholipids. Cholesterol and fatty acids adjust the transport and diffusion of molecular oxygen in membranes. The presence of cholesterol and saturated phospholipids decreases oxygen permeability across the membrane. Alpha-tocopherol, the main antioxidant in biological membranes, partition into domains that are enriched in polyunsaturated phospholipids increasing the concentration of the vitamin in the place where it is most required. On the basis of these observations, it is possible to assume that non-raft domains enriched in phospholipids containing PUFAs and vitamin E will be more accessible by molecular oxygen than lipid raft domains enriched in sphingolipids and cholesterol. This situation will render some nano-domains more sensitive to lipid peroxidation than others. Phospholipid oxidation products are very likely to alter the properties of biological membranes, because their polarity and shape may differ considerably from the structures of their parent molecules. Addition of a polar oxygen atom to several peroxidized fatty acids reorients the acyl chain whereby it no longer remains buried within the membrane interior, but rather projects into the aqueous environment “Lipid Whisker Model”. This exceptional conformational change facilitates direct physical access of the oxidized fatty acid moiety to cell surface scavenger receptors.     

Carrier Model for Active Transport of Ions across a Mosaic Membrane

The central purpose of this paper is to elucidate in a well defined system the meaning of certain phenomena and concepts associated with the active transport of ions. To this end a specific model for a carrier system which actively transports a single ionic species is analyzed and discussed in detail. It is assumed in this model that the carrier-mediated ionic transport occurs in regions of the membrane physically separate from those regions in which free ionic movement takes place,—coupling between the active and passive regions of the membrane occurring through local current flows. The model is seen to display the following characteristics: (a) Starting from identical solutions on the two sides of the membrane, there is produced a redistribution of ions; (b) with identical solutions on the two sides of the membrane there exists a potential difference across the membrane, i.e., the “pump” is electrogenic; (c) the “short circuit” current for symmetrical solutions is equal to the flux of the neutral ion carrier complex; (d) the rate of active transport (and hence of metabolism) is dependent on the ionic concentrations in the surrounding solutions. Throughout the paper comparison is made between features of the model and properties displayed by biological active transport systems, but there is no claim of an identity between the two.     

“探究培养液中酵母菌种群数量的动态变化”的分析和方案设计

“探究培养液中酵母种群数量的动态变化”是《课程标准》明确提出的活动建议。本课题的探究教学不仅有利于渗透新课程的教学理念,熟悉探究活动的一般过程,培养探究问题、设计和评价实验能力,建构实验研究的一般体系,而且在对本探究课题的结果分析中,引导学生构建数学模型,有利于培养学生透过现象揭示事物本质的洞察力和学生简约、严密的思维品质。     

运用概念图进行“植物的激素调节”的教学内容分析

教师在备课的过程中,对教学内容进行系统的分析和梳理是一个非常重要的环节.它是教师划分教学内容、确定教学思路、分配教学时间、设计教学活动以及选择教学策略的直接依据.而概念图恰恰可以有效地帮助教师对教学内容进行系统的分析和梳理.以高中生物学课"植物的激素调节"为例,介绍了利用概念图进行教学内容分析的一般步骤友详细过程.     

"光合作用发现史"教学的组织

以高中生物学"光合作用发现史"的教学为例,对科学发现史教学的目标确定、内容组织、教学策略等方面进行了一些富有启发性的探讨.强调科学方法训练既包括科学研究方法和科学思维方式,又涉及创新意识、科学态度和科学精神.     

The Excitable Membrane: A Physiochemical Model

The model of the excitable membrane assumes common channels for Na⁺ and K⁺; the two ion species interact within the pores through their electrostatic forces. The electric field varies across the membrane and with time, as a result of ionic redistribution. Ionic flow is primarily controlled by energy barriers at the two interfaces and by Ca⁺⁺ adsorption at the external interface. When the membrane is polarized, the high electric field at the external interface acting on the membrane fixed charge keeps the effective channel diameter small, so that only dihydrated ions can cross the interface. The higher energy required to partially dehydrate Na⁺ accounts for its lower permeability when polarized. Depolarized, the channel entrance can expand, permitting quadrihydrated ions to pass; the large initial Na⁺ flow is the result of the large concentration ratio across the interface. The effect at the internal interface is symmetric; Na⁺ crosses with greater difficulty when the membrane is depolarized. Na⁺ inactivation occurs when the ion distribution within the membrane has assumed its new steady-state value. Calculations based on parameters consistent with physicochemical data agree generally with a wide range of experiments. The model does not obey the two fundamental Hodgkin-Huxley (HH) postulates (independence principle, ion flow proportional to thermodynamic potential). In several instances the model predicts experimental results which are not predicted by the HH equations.     

"非生物因素对生物的影响"探究教学设计

介绍了探究教学模式在初中生物学实验教学中的实践与应用.课堂教学过程分为3个步骤:A.实验前讨论研究的问题并作实验设计;B.实验过程中获取数据;C.实验后学生讨论得出实验结论.整个教学过程中突出了学生的主动性和创造性,突出了如何将探究实验与学生获得的概念联系起来.突出了培养学生的逻辑型思维能力.     

Binding of Tobacco Mosaic Virus to Membrane Material Isolated from Tobacco Leaves

Binding of tobacco mosaic virus (TMV) to disrupted tobacco leaf membrane was studied. Membrane isolated from tobacco leaves was treated successively with (NH₄)₂SO₄, Li-diiodosalicylate and then pronase. TMV-binding substance was thus isolated in a soluble form. From enzymatic digestion experiments, it was suggested that the binding substance was composed of lipid and carbohydrate.