以核心概念为中心构建知识结构的课例分析

改进高三复习课的思路,引导学生围绕核心概念构建有逻辑关系的知识结构框架,训练学生综合应用学科观点、方法及知识解决实际问题,是当前进一步深化课堂教学改革的重要方向。精选适宜的复习载体材料,可有效激发学生复习的动力;精心设计层层递进的问题体系,可深入理解核心内容并使知识结构化;用核心概念和学科观点统领生物学知识可促进知识的综合应用。以高三专题复习"遗传信息的传递和表达"课例为载体,系统分析了以核心概念为中心的知识结构的构建过程,取得了良好的复习效果。     

复习课中重要概念的整合

在"绿色开花植物的生活方式"一节主题复习中,利用"结构与功能相适应"的生物学观点,将相关重要概念进行有机整合,引导学生重新审视所学生物学知识,有效提高复习课的效率,拓展了复习课的宽度和深度。     

“图式总结法”在初中生物学概念复习中的应用

应用概念图、思维导图等图式方法组织学生自主复习,有助于促进学生对重要概念的整体性构建和深入理解。以人教版《生物学》8年级下册的"生物的生殖和发育"等课的复习为例,初探组织学生应用图式总结已学概念的方法。     

以进化为主线带动“细胞的生物膜系统”复习教学设计

本节复习课围绕"细胞的生物膜系统",以进化为线索,围绕"生物膜的概念和作用"的教学目标,有效开展系统复习;并以问题作为驱动,带领学生合作探究,将高中有关生物膜的知识进行构建。     

“光合作用”单元复习的教学分析与组织

以"光合作用"一节复习课为教学案例,提出由整体到局部的教学组织原则和自上而下的教学设计思路。强调单元复习应在摸清学生已有知识储备的基础上,厘定在知识、能力、方法等方面的发展路向,努力促成学生的全面提高。     

浅谈生物学课的知识竞赛复习模式

复习课 (无论单元复习、专项复习还是总复习 )是日常教学中的重要环节。高效率的复习课对于学生的知识构建、能力提高具有重要的作用。在单元复习课教学中 ,我尝试着改变教学方式 ,将小组知识竞赛模式引入生物学复习课的教学。这样 ,以知识竞赛为依托既可提高学习兴趣 ,又可通过组内讨论达到促进组员共同进步的目的 ;充分调动每个组员的能动性 ,达到学习优秀者“吃得饱”、吃力者“吃得下”的效果 ,同时又可培养协作精神和表述能力。从学生反馈、课堂反映及测试结果来看 ,这种教学也确实既能继承传统复习课教学优点 ,又能在复习课上调动学生…     

社会性科学议题在高中生物学复习课中的应用

以"太湖水华的发生与治理"和"基因治疗"为例,介绍在高中生物学复习课中,如何利用社会性科学议题作为教学情境,引导学生构建概念体系、解决真实问题.     

高三生物学复习方法探讨——"典例"分析法

鉴于目前高三生物学课复习具有盲目扩大复习范围、过多依赖复习资料,造成信息量增殖,复习效率下降的现象,提出了"典例分析法",分别从"典例"的典型性、分析视角及价值所进行探讨,以期提高学生的思维能力,真正提升复习的价值.     

浅论探究性学习在高三生物专题复习课教学中的应用

在高三生物复习课教学中,如果只靠教师全面讲解,将所学知识机械地重复一遍,会让学生有“炒冷饭”的感觉。学生的学习兴趣和参与程度会大大降低,导致复习效率低下。因此,创造性地构建复习过程,与学生活跃的思维对接,提高复习效率,应是师生共同追求的目标。探究性学习是一种以问题为载体,以主动探究为特征的学习活动。教师要特别重视将探究性学习引入复习课,     

复习课的教改尝试

复习课是以巩固所学知识并提高运用知识解决实际问题能力为主要任务的一种课型。然而 ,教师为了追求知识的全面性 ,节约时间 ,往往采用“容器灌注”的方法 ,既剥夺了学生参与的时间 ,也把学生置于被动学习的境地 ,学生的学习积极性和学习效率受到极大的限制。因此 ,我尝试变换课的结构 ,力争恢复学生的主体地位 ,使复习课真正形成巩固、提高、拓展、创新的崭新局面。1　学生课前演讲进行复习导入复习课内容对学生来说已失去新鲜感 ,甚至认为已全部掌握 ,因而往往失去学习的主动性和积极性 ,失去对知识的进一步渴求。为了调动学生积极性 ,激…     

Role for dopamine in malonate-induced damage in vivo in striatum and in vitro in mesencephalic cultures

Defects in mitochondrial energy metabolism have been implicated in the pathology of several neurodegenerative disorders. In addition, the reactive metabolites generated from the metabolism and oxidation of the neurotransmitter dopamine (DA) are thought to contribute to the damage to neurons of the basal ganglia. We have previously demonstrated that infusions of the metabolic inhibitor malonate into the striata of mice or rats produce degeneration of DA nerve terminals. In the present studies, we demonstrate that an intrastriatal infusion of malonate induces a substantial increase in DA efflux in awake, behaving mice as measured by in vivo microdialysis. Furthermore, pretreatment of mice with tetrabenazine (TBZ) or the TBZ analogue Ro 4-1284 (Ro-4), compounds that reversibly inhibit the vesicular storage of DA, attenuates the malonate-induced DA efflux as well as the damage to DA nerve terminals. Consistent with these findings, the damage to both DA and GABA neurons in mesencephalic cultures by malonate exposure was attenuated by pretreatment with TBZ or Ro-4. Treatment with these compounds did not affect the formation of free radicals or the inhibition of oxidative phosphorylation resulting from malonate exposure alone. Our data suggest that DA plays an important role in the neurotoxicity produced by malonate. These findings provide direct evidence that inhibition of succinate dehydrogenase causes an increase in extracellular DA levels and indicate that bioenergetic defects may contribute to the pathogenesis of chronic neurodegenerative diseases through a mechanism involving DA.     

Scurvy in capybaras bred in captivity in Argentine

In order to determine if the absence of vitamin C in the diet of capybaras (Hydrochoerus hydrochaeris) causes scurvy, a group of seven young individuals were fed food pellets without ascorbic acid, while another group of eight individuals received the same food with 1 g of ascorbic acid per animal per day. Animals in the first group developed signs of scurvy-like gingivitis, breaking of the incisors and death of one animal. Clinical signs appeared between 25 and 104 days from the beginning of the trial in all individuals. Growth rates of individuals deprived of vitamin C was considerably less than those observed in the control group. Deficiency of ascorbic acid had a severe effect on reproduction of another population of captive capybaras. We found that the decrease in ascorbic acid content in the diet affected pregnancy, especially during the first stages. The results obtained suggest that it is necessary to supply a suitable quantity of vitamin C in the diet of this species in captivity.     

Changes in lactate dehydrogenase activity in chicken tissues in hyperthyreosis in ontogenesis

The lactate dehydrogenase activity in reactions of lactate oxidation and synthesis was studied in subfractions of the chicken brain, heart and liver at the embryonal, early postembryonal and adult stages of development after thyroxine administration. It has been shown that during embryogenesis thyroxine predominantly enhanced the rate of lactate oxidation in the mitochondrial tissues. A marked increase in the lactate synthesis was found in cytoplasm of the adult chicken tissues. Specificity of enzyme activity alterations was detected in the chicken brain during ontogenesis after thyroxine administration.     

SSTR5 ablation in islet results in alterations in glucose homeostasis in mice

Somatostatin (SST) peptide is a potent inhibitor of insulin secretion and its effect is mediated via somatostatin receptor 5 (SSTR5) in the endocrine pancreas. To investigate the consequences of gene ablation of SSTR5 in the mouse pancreas, we have generated a mouse model in which the SSTR5 gene was specifically knocked down in the pancreatic beta cells (betaSSTR5Kd) using the Cre-lox system. Immunohistochemistry analysis showed that SSTR5 gene expression was absent in beta cells at three months of age. At the time of gene ablation, betaSSTR5Kd mice demonstrated glucose intolerance with lack of insulin response and significantly reduced serum insulin levels. Insulin tolerance test demonstrated a significant increase of insulin clearance in vivo at the same age. In vitro studies demonstrated an absence of response to SST-28 stimulation in the betaSSTR5Kd mouse islet, which was associated with a significantly reduced SST expression level in betaSSTR5Kd mice pancreata. In addition, betaSSTR5Kd mice had significantly reduced serum glucose levels and increased serum insulin levels at 12 months of age. Glucose tolerance test at an older age also indicated a persistently higher insulin level in betaSSTR5Kd mice. Further studies of betaSSTR5Kd mice had revealed elevated serum C-peptide levels at both 3 and 12 months of age, suggesting that these mice are capable of producing and releasing insulin to the periphery. These results support the hypothesis that SSTR5 plays a pivotal role in the regulation of insulin secretion in the mouse pancreas.