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生物化学是研究生物的化学组成和生命过程中各种化学变化的科学,是研究生命的化学本质的科学。也是研究生命现象的重要手段。生物化学不但可以在生物体内研究各种生命现象,还可以在体外研究生命现象的某个过程。
首先来说说生物化学的静态部分。基础生物化学从第一章开始到第六章完,我们学习了细胞中各种组分的结构和功能,了解了小分子如何形成生物大分子,或进一步形成大分子聚集体。从了解蛋白质的元素组成开始,我们学习了核酸、酶、维生素、辅酶、生物膜。核酸作为生命的遗传物质,有DNA和RNA两种类型,对生命的延续以及新物种的诞生都提供了理论依据。新陈代谢是生物体进行一切生命活动的基础,而新陈代谢的进行又离不开酶的催化作用,因此,了解酶的作用和本质,为理解细胞中复杂的生命活动的顺利进行奠定了基础。然而我们都知道单成分的催化活性依赖于酶活性中心三维结构上靠得很近的少数氨基酸残基,而双成分酶必须与辅基或辅酶等蛋白质的辅助因子成分结合才能表现出酶的全部活性,于是维生素就成了不可少的一种物质,比如当体内缺乏维生素B2时人体就会引起口角炎、皮肤炎等病症,可见学习基础生物化学对我们的身体健康都是有益的。
从第七章开始。我们就学习了基础生物化学的动态部分,当然这个部分与静态部分是离不开的,且是建立在静态部分上进行的。这部分讲得最多的就是代谢,代谢包括物质代谢与相传伴的能量代谢。在分解代谢过程中,营养物质蕴藏的化学能便释放出来,比如糖类代谢生成水和二氧化碳,在这个过程中释放出大量的能量,供机体进行一切生命活动。不管是糖类、蛋白质、脂肪,还是核酸代谢对我们生命活动来说都是非常重要的,他们之间也存在着联系,而且这些联系有着不可忽视的作用。这些都是要通过必要的生物化学手段才能够去认识清楚,进而对解释、揭示生命起着很大的作用。
第十三章到第十五章,就介绍了DNA、RNA和蛋白质的合成。对这些物质合成所需要的原料、模板、酶以及生物合成的基本过程进行讲解。这对于我们去控制他们的合成,有了理论基础和可行性。当我们不需要他们合成时我们就可以通过一些手段来实现,比如我们可以用利福平、利福霉素去抑制RNA聚合酶的活性,对治疗结核等病症起了很大的作用。
基础生物化学与其他学科也有很多联系,我们大一是就已经学习了的有机化学在描绘生物大分子的性质上起了很大的作用,大二学习的微生物学对研究代谢途径和调控提供很多材料,比如说很多单细胞生物和一些病毒等。当然基础生物化学的形成于发展也推动了其他一些学科的发展,比如说DNA的三维结构推导出来后,综合遗传学与细胞学的研究成果,就诞生了分子生物学。
基础生物化学这门学科对我们的生活非常重要,也是我们学习今后的相关专业知识技能的必备基础,因此学好基础生物化学就是在为今后更加专业的学习奠基石。
生物化学是从分子水平揭示生命现象及本质的科学,是生物相关专业包括水产养殖学的学科基础课程。它对学生整合相关知识、构建完整的专业思维体系是极为重要的。但是,生物化学这门学科的内容多,信息量大,抽象难懂,而且内容前后交错,学生的学习和教师教学都有较大的难度。为了使学生在学习过程中更好地掌握这门学科,笔者介绍几种方法。
1、适时引入专业知识,激发学生探索兴趣
生物化学课程内容多,学生一开始就有畏难情绪,特别是生物化学的静态生物化学部分,主要介绍各种生物分子的结构、性质和功能,知识点多,内容枯燥,而且有些知识内容交错,学生不易理解。兴趣是最好的老师,为了激发学生的兴趣,在授课过程中除了课本上的知识外,从物质的化学结构和化学性质入手,以点带面,适时引入相关的专业知识,拓宽知识的深度和广度,并使学生意识到基础知识的重要性。例如,在讲蛋白质的性质时,用“点豆腐”来引入蛋白质的沉淀性质,用“点豆腐”的两种不同方式(加卤水或石膏、加葡萄糖酸内酯),形象地介绍要想获得活性蛋白质可以采取盐析、调节pH值至等电点的方式。
为了使学生把所学知识整合起来,可以引入一些与生活密切相关的知识。在糖化学中介绍肽聚糖中的糖链是由NAG和NAM通过β-1,4糖苷键相连,学生印象不深。在学习各种酶时可以通过介绍溶菌酶的作用机制,再回顾肽聚糖的结构,并且告诉大家溶菌酶其实普遍存在于人们的眼泪、鼻腔以及鸡蛋白、各种鱼类的体表粘液中,要想制备溶菌酶也不困难。这样,学生的兴趣大增,纷纷查阅资料。在讲糖类分类时,引入“功能性低聚糖”概念,这些低聚糖中的糖苷键多为α-1,2、α-1,3、β-1,3、β-1,4或β-1,6糖苷键,仅含有少量的α-1,4糖苷键。而动物消化系统中消化糖类的酶如唾液淀粉酶和胰淀粉酶主要水解α-1,4糖苷键,对其他类型的糖苷键的水解能力较弱甚至不分解,因而功能性低聚糖不能被动物消化酶消化。虽然低聚糖不能被动物直接利用,但由于它的结构和性质的特殊性,对动物消化道的改良方面却起到积极作用。
通过这些例子,一方面使学生深刻理解了物质的`结构决定功能的道理,另一方面也增加了趣味性,不但把遥不可及的抽象知识变为具体的研究内容,而且拓宽了学生的知识面,增强了专业自豪感。
2、抓住主线,构建知识框架
生物化学课程的信息量大,抽象而且难记,如果不能把握各知识点的内在逻辑关系,学生很容易迷失在知识的海洋中,一旦不能跟上教师的思路,学生就产生畏难情绪。这是一些学生成绩上不去的主要原因。针对这个情况,笔者在每一章的讲解过程中,把各知识点的逻辑关系作为课前复习和课后总结的重点内容,引导学生理清思路。指导学生自己对每章内容进行总结也是一个很好的构建知识框架的方法。各章的内容也不是孤立的,有很多共同之处。在静态生物化学这部分,不同物质的结构、性质和功能是主线,再从结构入手,层层剖析结构与性质和功能的关系,就能找出一般规律。例如维生素B2、维生素PP、维生素C虽然结构特点不同,但是都能自成氧化、还原体系,因而都能作为递氢体而发挥作用。
坎解物质的代谢和代谢调控部分时,对各个代谢过程进行比较,无论代谢过程多么复杂,只要清楚代谢发生的组织器官、发生的细胞器、初始反应物、终产物、关键步骤及关键酶、水及二氧化碳的产生、能量的转换形式及数量等主要特征,整个代谢过程也就基本清楚了。
3、适时设问,启发学生去思考
对教材内容进行适当调整,巧妙设问,及时解决问题。把生物氧化的内容安插到糖代谢这一章中,讲完糖酵解,留下一系列疑问:细胞质中糖酵解产生的NADH怎样生成ATP?为什么有氧条件下一分子葡萄糖糖酵解可以产生6个或8个ATP?然后引入生物氧化的概念和原理,最后解答细胞质中生成的NADH是如何通过苹果酸穿梭或甘油磷酸穿梭系统进入呼吸链完全氧化的。通过这样的调整,学生不但了解了葡萄糖有氧分解过程的细节问题,而且对整个过程也形成了完整的印象。在讲淀粉和糖原的结构时,可以留下疑问:为什么淀粉和糖原都只有一个还原端和许多个非还原端?这种结构特点有什么重要意义?可以先指出这种结构特点便于糖的迅速分解,具体细节则要到糖代谢内容中解答。
4、反复比较,把相关的知识串联起来
物质代谢途径虽然各不相同,但是都有一些相似的过程,在授课过程中,讲到其中一个时,可以先提出其他代谢途径的类似过程,反复提及,使学生印象深刻。例如,比较核苷三磷酸在糖代谢、脂代谢、蛋白质代谢过程中的大分子合成以及生物氧化的整个过程中的作用:核苷三磷酸除了作为核酸合成的底物以外,4种核苷三磷酸在糖、脂和蛋白质代谢过程中也发挥着不可替代的作用。ATP是各种物质代谢必需的能量货币,但是在不同物质的代谢中,ATP为活化物质所提供的高能磷酸键的数目是不同的,葡萄糖、甘油等含有羟基的物质,活化过程是磷酸化,只需要一个高能磷酸键,因此,ATP变为ADP;而脂肪酸、氨基酸中含有羧基,活化时都需要把羧基转变为酰基,需要消耗两个高能磷酸键,因此,ATP变为AMP。UTP是糖原合成过程中的必需物质,CTP是磷脂合成的关键物质,GTP则是蛋白质合成中必不可少的能量提供者。
生物化学是一门发展很快的专业基础课,而且是发展非常迅速的前沿学科,由于新理论、新知识、新技术的不断出现,使生物化学的研究日新月异,不断有新的研究成果产生,它的研究范围很广,涉及整个生物界,只要有生命存在,就有生化的过程,我校所学的是医用生化,它集中了动物生化和微生物生化的知识,生化的发展促进了医学的发展,是医学课程中很重要的课程,由于生物化学是从有机化学和生理学中脱离而发展起来的,其内容比较抽象,缩写符号多,代谢反应错综复杂且相互联系,理论点多、面广,因而师生普遍反映生物化学是一门难教、难学的课程。因此,如何将这些深奥难以理解的生物化学内容形象化、具体化、生动化,是我们每一位生物化学教师应该不断探索的问题。通过多年教学,我觉得在教学中应注意以下几个方面。
一、强化集体备课,激发群体思维
对于教材中的重点及难点章节采取警体备课,在备课时要发挥骨干教师的辐射作用,开展以他们为主讲人的备课活动,在集体备课前主讲人要广泛收集教学素材,注重理论和实践结合,成功的集体备课能让所有生化老师群体受益,取长补短,相互启发,互相促进,从而保持教学多元化。
二、授课时多结合临床病例,激发学生的学习兴趣
生物化学较强的理论性和抽象性是学生感到生物化学枯燥及学习被动的主要原因。兴趣是学习的动力,是力求认识事物的心理倾向,激发学习生物化学的兴趣是非常重要的。所以教学内容要侧重于将生物化学的基本理论、基本知识与临床工作联系起来,既能激发学生的学习兴趣,又有助于生物化学课程与后期临床课程和临床实践的密切配合。如在讲授酶时,把酶作用的最适温度概念和高烧对人体的危害、冬眠疗法、高温灭菌、低温保存生物制品等医疗工作措施联系起来。在讲核酸和蛋白质生物合成时,联系一些抗生素抑制细菌生长和抗癌药抑制癌细胞生长的机理,在讲述糖代谢时,可列举糖尿病病例,利用糖代谢知识分析糖尿病“三多一少”产生的原因及治疗方法。不但加深了学生对生物化学知识的理解,而且极大地激发了学生的学习兴趣。让学生觉得理论不再空洞,加快其领悟,提高了教学效果。
三、实施趣味引导式教学
生物化学中有许多原理比较深奥、难以理解,如果采用传统的直接讲授方法,学生必定会感到枯燥乏味,提不起兴趣,若在教学中讲述一些有趣的见闻、运用一些形象的比喻及提出一些启发性的问题,使深奥的理论浅显化、抽象的事物形象化、枯燥的知识生动化,必然会提高学生学习的兴趣。比如,在讲解呼吸链抑制剂鱼藤酮的抑制原理时,可以先讲古代日本渔民打鱼趣闻,他们用生长在海边的一种藤条状的植物在水中浸泡,鱼就会自然死亡,后来研究发现鱼的死亡是由于呼吸链被抑制,细胞缺氧而死亡,就把这种抑制剂称为鱼藤酮。这样的讲解,使学生很容易就记住了知识点。又如,在讲解三羧酸循环时,把循环过程比喻为操场,草酰乙酸比喻为运动员,乙酰辅酶A比喻为矿泉水,运动员沿着操场跑步,每跑一圈喝一瓶矿泉水,然后总结三羧酸循环的特点,每循环一圈,消耗一分子乙酰辅酶A,通过对这些问题的解答,可以使学生轻松地掌握这些内容,同时也提高了学生的思维能力。既能引起学生学习的兴趣,又能化解生物化学教学中的难点,起到事半功倍的效果。逐步启发学生,引导探究,层层深入,直至学生能主动地领会和掌握知识技能的方法。
四、利用多媒体教学,提高生化教学质量
多媒体课件可以充分利用各种媒体素材,生动形象地展示课堂内容,再现传统教学难以表述的内容,具有将抽象理论形象化、平面板书立体化、信息摄取多元化、教育过程人性化等特点,从而调动学生的积极性,吸引学生的注意力,提高学生的学习兴趣。多媒体教学具有图文并茂、动静结合的特点,使图片和动画内容生动活泼,直观性强,可帮助学生了解一些抽象的内容,并将这些内容清晰地展现在学生面前,增强学生对知识的想象力,调动学生思维的积极性。因此教师在制作课件时,先将一些深奥的理论知识转变为学生的感性知识,再通过教师的深入讲解,使之转化为学生的理性知识。另外,在多媒体教学中注意表格的应用,图表的作用在于提纲挈领地列举事物,便于记忆。图表格式的系统化、条理化、简明化,是记忆外储的一种良好形式,图表在多媒体教学中的广泛应用可以大大提高学习效率。绘制表格的基本原则是简单明了、避免杂乱繁琐。设计合理、精美的表格能起到一览诸要,便于记忆的作用。并且教师在多媒体教学中应与传统教学有机地结合,在讲授重点和难点时,适当应用提问、讨论和启发等多种教学方法,增加形体语言的交流,建立“教师―媒体―学生”相互作用的新教学模式。
总之,教学过程是教与学的互动过程。作为一名生化老师如何充分发挥自己的作用,还需在今后的工作中进行认真的总结和探索,找出更好、更有效的方法。
很多人认为考研中生物化学很难记忆的,不过这门课又非靠记忆不行。
我的经验是首先了解生物化学这门课的整体框架,看目录就行,知道大致讲了那些内容,如糖代谢脂肪代谢等等。做到心中有数。
然后分单元看时,需要不时回忆一下,我现在所学习的内容是属于那个大章节的,同时你又可以想象一下这个大章中我已经复习了那些,到这个章节结束时,你再回忆一下所有的内容,并拎一下重点。在不看书的情况下,你能想起多少,能想起的也就是你的收获,想不起来的,翻书补充一下。
这样一步一步看下来,第一遍看会很累的,因为进度很慢,不时地要回过去,不时地要复习以前记的一个个循环。但是如果这第一步你挺过来了,接下来的就是温故而已,会很轻松,心情也很放松,因为你看到一道题,一般你都能找到它的家。然后稍微回忆一下就能答题了。
当然到最后临考时,你也并非能记得全部,但是你要想想你不记得的地方也不一定考到啊,所以就不必过于担心啦。可以胸有成竹地上考场。
其实每次在考生物和化学这两门课的时候,都会很紧张,也许是知识点不扎实,自己的底气不足。要加倍努力补充自己的知识点了。
一、合理应用多媒体和传统教学法
一方面,多媒体教学具有直观、生动的特点,它能将抽象概念具象化,通过图片、动画形式将生物化学概念和过程进行形象展示,较传统教学手段有着显著的优势。在现代教学中,多媒体已然成为了教学中的主导教学方式,传统板书教学的利用已越来越少。例如,生物化学中关于分子生物学,如蛋白质、核酸以及基因复制、表达和蛋白质合成的内容,就十分适合使用多媒体教学。分子生物学是从分子水平进行的研究,文字叙述抽象,学生难以理解,而黑板板书也难以准确传达,这时适当使用图片和动画视频进行展示,能让学生在三维空间中观看分子结构,将基因表达调控的动态过程以生动逼真的动画模拟进行演示,辅以老师的讲解,使得学生在观看过程中觉得新鲜有趣,激发学习兴趣,更好理解教学内容,达到理想的教学效果。
另外,除理论教学,实验教学中多媒体的应用也显得十分重要。学生在实验之前观看实验教学录像,可以近距离观察实验操作细节,不仅能够复习已学技能,还能够清楚地学习实验新技术,减少了实验教学中学生操作不规范、不正确的情况发生。另一方面,多媒体教学固然在形象和生动上具有优势,但如果教师一味关注生动趣味性,忽略教材结构及文字内容,就会使得学生在复习中往往感到无从下手,觉得书本内容生疏、晦涩难懂,其实并不利于学生的自主学习和对知识体系的整体把握。这时,教师就要多引导学生关注教材,理清课本的思路和篇章结构,帮助学生构建知识体系,用板书的传统教学手段带领学生搭建学习框架。例如,当讲解物质代谢过程时,在结束物质基本代谢反应的教学后,教师有必要将物质代谢之间的联系进行归纳总结,在学生已掌握的知识基础上,将章节内容相互关联,形成系统的知识结构。譬如糖代谢一章包括许多糖代谢途径,如糖的氧化分解,糖原合成、分解,糖异生,糖转化为其它非糖物质等,各章节知识点多、散、杂,老师此时应当充分利用传统教学手段,以血糖平衡为中心,引导学生思考各途径和血糖恒定之间的关系,用文字和图线将血糖的来源去路标识,将各个代谢途径的意义和血糖平衡进行联系,使得学生将糖的所有代谢途径串联在一起,形成关于体内糖代谢的统一认识,这对于生物化学的学习和认知是十分重要的。总之,在理论和实践的教学中,教师应当根据教学内容适当选择教学方法、手段,将现代教学方法和传统板书教学方式有机结合。
二、突出生物化学实用性,启发学生自主思考
生物化学是一门和临床及生活、生产实践密切相关的学科,通过对日常生活和临床实例的结合,能够不断有效地激发学生在生活中探寻原理的热情,并利于学生更好地理论联系实际,掌握相关理论知识。例如,在讲述绪论内容时,可以通过介绍日常生活中应用生物化学为人类服务的例子,如通过介绍人们利用加酶来增强洗衣粉的去污能力,利用微生物发酵生产酸奶、醋、酱油以及卤水点豆腐的食物制作等,来阐明生物化学是一门实用性强,和人们的生活息息相关的学问,对于拉近学生距离,提高学生学习生物化学的兴趣有着极大的促进作用。在进行其他章节理论的教授时,也要密切联系实际和临床,注重培养学生思考、分析问题的能力,启发学生用所学知识提出解决问题的方法,让学生既听得明白,又能够有所提高和拓展,达到学有所得、学以致用的目的。例如,在讲蛋白质的变性问题时,学习到高温高压、强酸强碱、射线辐射以及重金属等都是蛋白质变性的诱发因素,这时候就要引导学生思考,在实际生活和临床中可以怎样利用或防止蛋白质的变性来为人类服务。然后让学生思考并解释为什么高温加压、紫外照射可以消毒灭菌,低温可以保存生物蛋白制品,可以利用蛋白为重金属中毒解毒等,不仅能使学生在思考过程中加深理解,还能扩展知识。
三、关注实验教学内容的临床实用性,培养学生严肃认真的科学精神
实验是加深学生理解、培养学生动手能力的重要教学部分。生物化学实验种类繁多,不同专业实验教学侧重点有所不同,且由于高职高专学制短,实验课时都被大幅缩减,因此就要求教师必须要认真考察实验条件,结合各自学校硬、软件设施条件的实际,从临床适用角度,为不同专业的学生选择适当的实验教学内容。例如:临床检验中的血清蛋白电泳、血糖测定、血清胆固醇测定、血清甘油三酯测定、血清尿素测定等实验,涉及的实验原理既是理论教学的重点,也是生物化学在临床中常见的检测应用;并且,对于一种临床指标,通常有多种实验方法进行检测,教师应该重点选择和当前临床实践最贴近,并且操作简单、结果准确、操作安全的实验方法。通过实验,学生能够了解如何将理论应用于实践,有助于学生思维的拓展和创造力的发掘。另外,教师还可以根据学生情况,适时适当引入设计性实验,引导学生自己设计实验方法,培养学生运用理论和实验操作技能分析、解决问题的能力。此外,医学生物化学的实验教学目的也在于培养学生认真、客观、严肃的研究精神以及踏实、负责的医学态度。因此,相比要求学生按照标准操作得到正确的实验结果,教会学生如何分析实验结果并得出客观的结论,进行实验结论分析则显得更为重要。这就要求教师在实验过程中,要让学生完全清楚实验原理和操作,理清每一步实验步骤的操作和意义,在实验结束后,针对自己的实验结果得出全面、客观的实验结论,达到实验教学的培养目的。
综上,生物化学教学是基础医学教学的重要组成部分,促进生物化学教学改革是促进学科优化、提升教学质量的重要环节。通过不断教学实践改革和探索,建立和谐积极的教学氛围,促进学生学习,才能促进提高生物化学教学质量,帮助培养出理论扎实、踏实认真的优秀医学人才。
1不断提高职业道德修养
教师职业道德修养不仅影响医学教师的发展,也影响学生的学习和发展。高校医学教师肩负着培养高级人才的重任,教学效果固然重要,但医学教师的职业态度、思想道德和个人修养都会对学生的知识体系构建、世界观的形成产生重大影响。除了积极参加单位组织的学习外,医学教师更要自觉地了解名人传记和模范事迹,自我鼓励。在教育和教学实践中,在处理师生之间、教师之间、教师与其他成员之间的关系中,才能辨明是非,才能辨别善恶,才能对照、发现和纠正自己的缺点和不足,从而培养自己良好的思想道德水平。目前,我校新聘教师要先后通过教研室、学院及大学不同层面严格的考核,最终选择师德高尚、知识渊博的人才到教师岗位,革除忽视师德、只重学历的'弊端。建议:第一,师德的表现应与工资、岗位和职称挂钩。第二,建立监督制度,结合行政与社会监督力量,明察暗访,并设立“师德信箱”,通过各种手段鼓励教师严于律己,以达到较高的思想境界。
2始终重视提高教学能力
教师的首要任务是教学,教学能力的提高是对教师的基本要求。近年来,随着大学招生规模的扩大和师资的新老更替,大批年轻教师被引进。由于缺乏教学经验,知识储备不足,难以厚积薄发,使得教学捉襟见肘,学生感到索然无味,存在青年教师的教学能力不足的现象。例如,本人所在教研室共17名在岗人员,其中35岁以下教师高达70%,因此,对于青年教师教学能力的培养应格外重视。看法如下:第一,现有培训结束后每个人都会颁发一个证书,无关乎你培训表现、出勤等,纯属“走过场”。因此,建议加强培训制度法律化,通过立法的形式,把参加在职培训作为医学教师终身在职教育。第二,由年资高、经验丰富的教师对青年教师进行“一对一”带教,要从最基本的做起,如,针对实验课的“基本操作及标准曲线法测定未知硫酸铜浓度”,不仅要指导青年教师的教学过程,还要“手把手”完成整个实验。课后,青年教师要积极进行教育教学反思,如,写反思日记、观摩教学、讨论教学等,再与带教老师沟通,以便提高自己的教学能力。第三,青年医学教师要努力提高专业水平,做好专业知识积累,保持与专业前沿同步。
3努力提高教师科研能力
教师教学工作本身需要良好的科研能力,这样才能去追求创新,“创造”良好的教学效果,以适应教育改革和发展的需要。研究意味着要在实践中探索,再反馈于理论,医学教师必然会科学地收集、分析并加工知识,最终达到科研促进教学的目的。具体看法如下:第一,相关部门应建立规范合理的科研管理体系、公正透明的竞争机制和激励措施。项目申报组织校内专家进行初审,提出修改意见并反馈,以便申报者及时改进。第二,大学应创造更多条件让中青年医学教师通过各种渠道和方式参加继续深造,尤其对学科带头人和突出人才,保持优秀骨干不断拓展新的研究领域。第三,形成一支相对稳定的科研队伍,通过“请进来,走出去”的方式来提高科技人才的培养速度,作为后备军,必须加大青年医学教师科研能力的培养,建立健全一套行之有效的人才培养机制。在影响学生发展的众多因素中,医学教师是教育的直接实施者,又是一个专业队伍,相比其他任何因素,都具有明显优势。因此,作为教师都不能妄自菲薄,只有不断提高自身的综合素质,才能有效的完成各项任务,真正推进教育的健康发展。
摘 要:本文通过对生物化学学习方法的探讨,阐述了合适的生物化学教学方法。
关键词:生物化学 教学方法 知识框架 学习方法
生物化学是生物学与化学交叉的边缘学科,与医药的关系十分密切,是医学、药学等专业的一门重要专业基础学科。由于其概念多,代谢复杂,学生普遍反映不好学。我们可以通过各种不同的教学方法,帮助他们完成对生物化学的整体学习,具体方法如下:
一、搭建生物化学知识框架,从整体上认识生物化学
很多学生学了一学期的生物化学,最后却不知道自己在学什么,就像一首诗所描写的:“横看成岭侧成峰,远近高低各不同。不识庐山真面目,只缘身在此山中。”也就是说他们对其中的内容可能知道,但一想就不清楚了。终其原因是不能跳出来看看其“庐山真面目”。针对这一点我们可以引导学生搭建生物化学的知识框架,使他们能从整体上认识生物化学。
生物化学可以分为两大部分:一是静态生化,二是动态生化。对于职业学校的学生来说,静态生化主要讲的是蛋白质、核酸的组成、结构、理化性质、结构与功能的关系及生物学功能五大方面的内容,以及维生素的一些简单知识。酶的化学本质是蛋白质,在组成、结构、理化性质上与蛋白质是相似的,静态生化主要讲的是它的催化作用,包括催化机理、影响催化作用的因素等。蛋白质和核酸又可对比起来学习,在以上五方面进行对比,既容易区别两者又容易记忆。这样理顺,学生就能大致上明白在静态生化这一块中学习了一些什么内容,学习起来也不至于盲目。动态生化主要讲的是四大物质(糖、脂类、蛋白质和核酸)的代谢。一般来讲四大物质代谢包括合成代谢和分解代谢,书中对这四大物质的两类代谢的讲解是有侧重的。四类物质的代谢是相互关联的,其间的关系需要给学生讲明。比如:糖的分解代谢能产生合成脂肪的原料,脂肪的分解代谢既能进入到三羧酸循环彻底氧化分解,又能通过糖异生转化为糖。蛋白质的合成与三种RNA相关,核酸的合成又与某些蛋白质相关。每种物质的分解代谢或合成代谢与其结构都是有联系的,研究四大物质的结构,对于理解和联系四大物质代谢是很有好处的。静态生化讲的是物质基础,动态生化讲的是生命运动基础,两者相互联系。因此,我们要带领学生明确知识框架,认识生化,为更好地学习生化打下基础。
二、利用对比法、模型法、常识法等学习方法理解知识
知识框架有助于学生学习时明确方向,看自己到底学到什么地方了,使知识重现变得容易起来。而对于具体知识的理解还是需要花些工夫的,我们可以引导学生利用对比法、模型法、常识法等学习方法进行学习。
比如:蛋白质的一级、二级、三级、四级结构的定义就可以与DNA的一级、二级、三级结构对比起来学习。以最重要的一级结构为例:蛋白质的一级结构指的是由氨基酸之间通过肽键连接并按一定顺序排列构成的大分子化合物。DNA的一级结构指的是由脱氧单核苷酸之间通过3′,5′-磷酸二酯键连接并按一定顺序排列构成的大分子化合物。这两个概念定义的方式是相同的,都包含基本组成单位(蛋白质:氨基酸;DNA:脱氧单核苷酸)、连接键(蛋白质:肽键;DNA:3′,5′-磷酸二酯键)等信息。蛋白质与蛋白质、DNA与DNA之间之所以有区别,就是因为它们的排列顺序不一样。根据这三点信息,学生对这两个定义就能理解得很深刻,并且了解它们的基本组成单位和连接键。这样的例子还有很多,比如蛋白质的变性与核酸的变性,必需脂肪酸与必需氨基酸等。
利用模型记忆也是一种很好的方法。这里所说的模型并不是真正的模型,而是自己在脑海里构建的物象。比如蛋白质的合成就可以把过程想成是在装配机上进行的一系列操作,学习蛋白质合成只是把装配机的运行速率放慢,并分解每一个动作。多个rRNA进行蛋白质的'合成,就像在工厂里进行流水作业,这样一想,生化里非常抽象的蛋白质生物合成就变得形象化了。每一个要进行加工的物品(氨基酸)都要进行初加工,把氨基酸接到tRNA的氨基酸臂上。初加工过的氨基酸进入到装配机里进行装配。每一个装配过程包括:进位、转肽、移位和脱落。四个步骤的作用就是把氨基酸接到已经合成好的肽链上,然后从tRNA上脱落下来。这样把合成的过程用语言很形象地讲出来,学习起来就要容易些。形象的内容比抽象的内容记忆起来要容易得多。这样的例子还有核酸的合成,脂类的合成,糖元的合成等。
以日常生活的常识与生化知识相联系理解学习生化也是很简单易行的方法。比如同工酶,其定义为:催化同一种化学反应,而其酶蛋白结构组成,理化性质及免疫学性质上都有所不同的一组酶。仔细理解“同工”二字,“同”是相同的意思,“工”即工作。同工酶不就是指做同一种工作的酶吗?既然是做同一种工作的酶,那么它们的结构组成、理化性质和免疫学性质必然不同,如果相同的话,那就是相同酶了。这样理解,这个定义学起来也就容易了。比如:复制、转录、三连体密码等均可如此记忆。再如糖的生理学作用,主要有两条:①主要的能源物质;②生物体的重要组成成分之一。米饭、面食等是人类生存的主食,这些物质的主要成分就是糖。糖在身体中不仅有消耗,同时还有吸收和贮存,那么必然是生物体的组成成分。这样糖的生物学作用就不容易混淆了。我们可以这样学习的例子还有影响酶促反应速度的因素、有氧氧化的生理意义等。
奥苏伯尔说过:“影响学生最重要的原因是学生已经知道了什么,我们应当根据学生原有的知识状况去进行教学。”教师应该先对学生在生活中对这些知识了解到什么程度,有什么样的实际经验可以借用作一个细致的思考。这就要求教师在备课时要掌握教材的整体结构,深入了解学生的现状与需求;广泛搜集相关资料,合理取舍讲课的内容;帮学生从已知的知识过渡到未知的知识,形成专业的思维方式,使学生不但学会学习这门课,更能举一反三,学会学习。
active center.
活性中心
a specialized region of an enzyme where the enzyme interacts with the substrate and catalyzes its conversion to products. many aminoacyl residues contribute to the active center.
adenylyl cyclase.
腺苷酸环化酶
an enzyme that catalyzes the synthetic reaction of cyclic amp from atp in response to hormones such as epinephrine and glucagon.
alanine-glucose cycle.
丙氨酸-葡萄糖循环
a cooperative pathway between liver and muscle in which the ammonia and carbon from amino acid metabolism are removed from the muscle as alanine, taken up by the liver, transaminated to pyruvate, converted into glucose, and shipped out back to the muscle.
albumin.
清蛋白
albumin makes up 50% to 55% of the proteins of plasma and is thought to be the main contributor to osmotic pressure of blood. another important function is that albumin has very broad and non-specific binding properties.
allosteric enzyme.
变构酶
allosteric enzymes are enzymes whose activity at the catalytic site may be modulated by the presence of allosteric effectors at an allosteric site. allosteric means “occupy another space”, so an allosteric effector occupy another space, giving an effect on enzymes.
allosteric regulation.
变构调节
a type of enzyme regulation in which an effector binds to one site on the enzyme and increase or decreases the activity at another site. allosteric regulation provides a rapid means for regulation of their activity.
aminoacyl-trna synthetase.
氨基酰trna合成酶
the enzymes are responsible for the recognition and attachment of the 20 amino acids to specific trna.
anticodon.
反密码子
the template-recognition site on trna is a sequence of three bases called the anticodon, which recognizes a complementary sequence of three bases on mrna.
apoprotein.
载脂蛋白
the protein moiety of a lipoprotein. they mediate the interaction between lipoproteins and tissues.
apoptosis.
细胞凋亡
programmed cell death. the programmed cell death is tightly regulated, which plays important roles in physiologic processes. typical morphologic changes can be observed in apoptosis. one or more endonucleases degrade dna, leading to characteristic ladder of discrete dna fragment on electrophoresis.
bile salts.
胆汁酸盐
salt form of bile acids and their conjugates. since bile contains significant quantities of sodium and potassium and the ph is alkaline, it is assumed that the bile acids and their conjugates are in a salt form, so called “bile salts.”
biotin.
生物素
a cofactor involved in carboxylation reactions. most enzymes that catalyze the atp-dependent addition of co2 to a substrate (like acetyl-coa carboxylase) requires the cofactor biotin.
calcitonin.
降钙素
a 32-amino-acid peptide secreted by the parathyroid. the dominant biological action of calcitonin is to mediate a lowering of serum calcium levels. the hypocalcemic and hypophosphatemic effects of calcitonin are believed to be due to an inhibition of pth-mediated calcium resorption.
calcium-binding protein.
钙结合蛋白
1,25(oh)2-d3 stimulates gene transcription and formation of specific mrna that codes for “calcium-binding protein”, also called “calbindin”. three distinct vitamin d-induced “calbindin” have been isolated. two of them are found exclusively inside the intestinal and kidney cells, which are actively involved in calcium translocation.
calmodulin.
钙调蛋白
a ubiquitous calcium sensor in eukaryotes, regulates the activities of many intracellular proteins. the binding of ca2+ to multiple sites in calmodulin induces a major conformational change that converts it from an inactive to an active form. activated calmodulin binds to many enzymes and modifies their activities.
camp.
环化腺苷一磷酸
second messenger for increased demand for energy and glucose. camp activates camp-dependent protein kinase. increased camp levels are associated with increased protein phosphorylation. increases in the camp concentration cause activation of glycogen degradation, increased fatty acid breakdown, stimulation of glycolysis in muscle, and stimulation of gluconeogenesis in the liver.
camp-dependent protein kinase,pka.
依赖camp的蛋白激酶
most effects of cyclic amp in eukaryotic cells are mediated by the activation of a single protein kinase. this key enzyme is called protein kinase a or camp-dependent protein kinase, which alters the activities of target proteins by phosphorylating specific serine or threonine residues.
capping.
帽子生成
putting a 7-methylguanosine triphosphate on the 5’ end of an mrna molecule. capping is involved in the recognition of mrna and may increase the stability of the rna by preventing the attack of 5’exonucleases.
carnitine shuttle.
肉碱穿梭
gets fatty acyl groups into mitochondria. fatty acyl-coa in the cytosol is transferred to carnitine to make fatty acyl carnitine, which is transported into mitochondria. once inside, the fatty acyl group is transferred to coa and the carnitine is returned to the mitochondrial membrane.
catabolic pathway.
分解代谢途径
degradative metabolism. catabolic pathways involve oxidative processes that release free energy.
catabolic repression.
分解代谢阻遏
catabolic repression means that an intermediate in a sequence of catabolic enzyme-catalyzed reactions has ability to repress synthesis of catabolic enzymes.
catabolite gene activator protein, cap.
分解(代谢)物基因激活蛋白
a camp-binding protein that is capable of stimulating transcription by binding to certain promoter sites. it consists of two subunits, each of which contains a dna-binding domain and a camp binding domain.
cdna library.
cdna文库
a library is a collection of recombinant clones. cdna library represents the population of mrna in a tissue. see also cdna.
cdna.
互补dna
complementary dna. cdna copies from a population of cytoplasmic mrna using enzyme reverse transcriptase, converting the cdna single strands to double-stranded dna. the reverse transcriptase copies rna templates into dna-rna hybrids. after the rna in these hybrids is specifically destroyed, double-stranded dna may be produced by dna polymerase. cdna is a copy of an mrna so that it contains only the exon sequences.
cis-acting element.
顺式作用元件
this word described the regulatory interactions between two dna sequences on the same gene. an enhancer or repressor sequence in the dna is a cis-acting element or factor that affects the transcription of the gene.
cistron.
顺反子
a stretch of dna that carries the information for a polypeptide chain is called cistron.
clone.
克隆
group of cells or sequences of dna that are identical with a single parental cell or molecule.
coding strand.
编码链
the coding strand of dna has the same sequence as that of the rna transcript except for t in place of u. it is so-called because it matches the rna transcript that encodes the protein. the coding strand is also known as the sense strand.
codon.
密码子
each amino acid in a protein is specified by an mrna sequence of three nucleotides, which is called a codon.
coenzyme.
辅酶
a molecule bound to an enzyme and is essential for its activity. the coenzymes allow the enzyme to have functional groups that are not available from the side chains of the amino acids.
competitive inhibition.
竞争性抑制
substrate and inhibitor combine at the same site and result in raising the apparent km for the substrate.. in competitive inhibition, inhibitor can be completely displaced by a high concentration of the substrate.
configuration.
构型
the stereochemical arrangement of atoms in a molecule. configuration cannot be changed without breaking and reforming covalent bonds.
conformation.
构象
differences in rotation around bonds. the conformation of a molecular can be changed by simply rotating groups around single bonds.
conjugated bilirubin.
结合胆红素
adding glucuronic acid molecules to bilirubin. hepatocytes perform the process and convert bilirubin to a water-soluble form.
cosmid vector.
柯斯质粒载体
a special class of artificially constructed e.coli plasmids that carry the λ cos site, which allows them to be packaged intoλphage particles for efficient introduction into bacteria.
creatine kinase.
肌酸激酶
kinases incorporate phosphate from atp into the substrate. creatine kinase converts creatine to creatine phosphate, a major energy reserves in muscle.
de novo synthesis.
从头合成
biosynthesis of nucleotides with simple materials. purine and pyrimidine ribonucleotides are synthesized via two pathways, in which the purines are built as nucleotides via phosphoribosyl intermediates, whereas the pyrimidine ring is completed to the stage of orotate before coupling to ribose.
degenerate.
简并
more than one codon can specify the same amino acid and all codons are unambiguous in that each specifies no more than one amino acid.
denaturation.
变性
destroy the secondary, tertiary, and quaternary structure of a protein, dna, or rna molecule.
dna damage.
dna损伤
dna damage is that changes in the dna sequence resulted from copying errors and the effects of various physical and chemical agents or carcinogens,which alters one or more nucleotides in dna.
dna polymerase.
dna聚合酶
the principal synthetic enzyme, dna polymerase, extends the primers in the 5’ to 3’ direction by catalyzing addition of deoxyribonucleoside 5’-phosphates to the primer 3’ends. synthesis proceeds in the 5’ to 3’ direction as the template strand is read in the 3’ to 5’ direction.
dna replication.
dna复制
generation of a new copy of double-stranded dna from a parental dna molecule.
domain.
结构域
some polypeptide chains fold into two or more compact supersecondary structures. these compact globular supersecondary structures are called domains, which is one level of protein’s structures between secondary structure and tertiary structure.
effector.
效应剂
a class of small molecules capable of binding at a regulatory site. the binding of an effector changes the conformation of the enzyme so as to alter the kinetic properties of the catalytic site.
enhancer.
增强子
the sequence elements that can increase the rate of transcription initiation of eukaryotic genes. enhancers have no promoter activity of their own but they can exert their stimulatory actions over distances of several thousand base pairs.
enterohepatic circulation.
肠肝循环
the primary bile acids are synthesized in the liver and the secondary bile acids are formed in the intestine. the secondary bile acids are absorbed in the intestine, returning to the liver then recycle between intestine and liver, which is known as the entero-hepatic circulation.
epidermal growth factor (egf) .
表皮生长因子
epidermal growth factor can stimulates growth of many epidermal and epithelial cells. also see “growth factor”.
essential amino acid.
必需氨基酸
the amino acids that humans can not synthesize. the human diet must contain these amino acids to support growth or maintain health.
exon.
外显子
regions that are retained in the mature rna.
fad.
黄素腺嘌呤二核苷酸
flavin adenine dinucleotide. fad is derived from vitamin riboflavin, which serves as cofactor for oxidation and reduction reactions.
fat.
脂肪
mainly stored as triglyceride in adipose tissue. the adipose tissue releases fatty acids by the activation a hormone-sensitive lipase that catalyzes the hydrolysis of the triglyceride. the fatty acids are then transported through the serum and oxidized via b oxidation in the tissues to yield energy.
feedback inhibition .
反馈抑制
feedback inhibition refers to the inhibition of the activity of an enzyme in a biosynthetic pathway by an end product of that pathway.
ferritin.
铁蛋白
intracellular form of iron storage. it stores iron that can be used as condition requires.
fh4.
四氢叶酸
tetrahydrofolate. a reduced form of folic acid involved intimately in one-carbon transfer reactions.
gene.
基因
a stretch of dna that carries the information for a polypeptide chain is called gene or cistron. also see cistron.
genome.
基因组
total information of gene contained in a cell, an organism or a virus.
genomic dna library.
基因组dna文库
fragments of dna from the genome of some organism. they are prepared from the total dna of a cell line or tissue by performing partial digestion of total dna with a restriction enzyme that cuts dna frequently. it contains exons, introns, untranslated regions that can occur in dna.
glucogenic amino acid.
生糖氨基酸
the amino acid that yield pyruvate or citric cycle intermediates.
gluconeogenesis.
糖异生
making glucose or glycogen from noncarbohydrate. the term used to include all mechanisms and pathways responsible for converting noncarbohydrate to glucose or glycogen.
glycerol-a-phosphate shuttle.
a-磷酸甘油穿梭
get electron from cytoplasmic nadh into the mitochondria so that 2 atps can be made by oxidation of the nadh. the enzymes of the shuttle in mitochondria is linked to the respiratory chain via a flavoprotein.
glycolysis.
酵解
metabolic pathway that provides pyruvate as fuel to the citric cycle or for fat synthesis. in the absence of oxygen, lactate is produced from the pyruvate to regenerate nad+ so that the pathway can continue to work in the absence of oxygen.
gout.
痛风
it is an inherited metabolic disease that affects the joints and kidneys caused by hyperuricemia. though some patients have a partial deficiency of hypoxanthine-guanine phosphoribosyl transferase (hgprt), it is not sole cause of the disease.
growth factor.
生长因子
small polypeptides (more properly called cytokines) that stimulate the growth of particular classes of cells. the factors have a variety of effects, including changes in the uptake of small molecules, initiation or stimulation of the cell cycle, and ultimately cell division. examples of secreted cytokines are egf (epidermal growth factor), pdgf (platelet-derived growth factor), and insulin.
guide rna.
指导rna
guide rna is a sequence that is complementary to the correctly edited mrna.
hairpin structure.
发夹结构
a double-helical stretch formed by base paring between neighboring complementary sequences of a single strand of dna or rna.
helicase.
解链酶
an enzyme whose activity involved in dna replication that relieves the strain associated with unwinding the dna double helix during replication.
heme.
血红素
a cofactor consisting of a porphyrin ring containing an iron atom. heme has different functions depending on the protein that used them as a cofactor. heme are used to carry oxygen without oxidizing it in hemoglobin and myoglobin, but in other proteins, like cytochrome p450, the heme iron produces a very reactive iron-oxygen species at the active site.
hemoglobin.
血红蛋白
hemoglobin is the oxygen-carrying system found in erythrocytes, which transports oxygen from the lungs to all tissues of the body. the quaternary structure of hemoglobin confers its allosteric properties that adapt it to its biologic roles and permit its precise regulation.
hexokinase.
己糖激酶
responsible for the phosphorylation of glucose for entry into glycolysis, glycogen synthesis, or the pentose phosphate pathway.
hnrna.
不均一核内rna
heterogeneous nuclear rna. they are formed in the nucleus that is a precursor to mrna, which has both the intron and exon sequences.
hormone response element, hre.
激素反应元件
a specific dna sequences capable of binding activated receptors. these elements regulate the gene expression. both steroids and peptide hormones exert their effects on transcription through hres, but the initial reactions are different.
housekeeping gene.
管家基因
the genes that are expressed at a reasonably constant rate and not known to be subject to regulation.
induction.
诱导
synthesis of a particular protein in response to a signal stimulation in cellular metabolism. for example, the synthesis of an enzyme can be induced by its substrate.
intron.
内含子
the mosaic nature of eukaryotic genes is discontinuous. the primary transcript of a gene contains the regions that are not present in the mrna. regions that are removed from the primary transcript are called introns.
isoelectric point.
等电点
the ph at which a molecule has a net zero charge.
isomerase.
异构酶
an enzyme that catalyzes an intramolecular rearrangement.
isozyme.
同工酶
distinct physical forms of an enzyme with the same catalytic activity. separation and identification of isozymes is of diagnostic value.
jaundice.
黄疸
when bilirubin in the blood reaches a certain concentration, hyperbilirubinemia exists and bilirubin diffuses into the tissues, which then became yellow. the condition is called jaundice.
ketogenic amino acid.
生酮氨基酸
an amino acid that yields only acetyl-coa. they can not yield pyruvate or tricarboxylic acid cycle intermediates.
ketone bodies.
酮体
acetoacetate, hydroxybutyrate and acetone. at high rate of fatty acid oxidation, the liver produces considerable quantities of acetoacetate and hydroxybutyrate. the former continually undergoes spontaneous decarboxylation to yield acetone. ketone bodies are metabolized in muscle and brain as an energy source.
km.
米氏常数
if an enzyme follows hyperbolic kinetics, the km is equal to the substrate concentration at which the reaction rate is half its maximal value.
ligase.
连接酶
a ligase catalyzes the joining of two pieces of dna covalently. dna ligase joins the backbone phosphates in a phosphodiester bond.
lipids.
脂类
lipids consist of a diverse set of hydrophobic molecules including triglycerides, phospholipids, steroids, and so forth. it is soluble in organic solvents like chloroform or ether.
malate-aspartate shuttle.
苹果酸-天冬氨酸穿梭
gets electrons from cytoplasmic nadh into the mitochondria so that 3 atps can be produced by oxidation of the nadh.
mitogen-activited-protein kinase ( mapk).
有丝分裂原激活蛋白激酶
mitogen-activated protein kinase (mapk) is one of the most ancient signaling molecules and is involved in multiple cellular processes, including cell proliferation, cell growth, and cell death.
messenger rna (mrna).
信使rna
the rna in cytoplasm that serve as templates for protein synthesis. the primary rna transcript is processed to mrna by adding a cap and a tail and removing introns.
nad+-nadh.
辅酶i
nicotinamide adenine dinucleotide. nadh is an electron carrier. nad+ accepts two electrons and a proton from substrates and ultimately transfers them to the electron transport chain to make three atps and h2o.
nicotinic acid.
尼克酸
a vitamin that serves as a source of the pyridine ring of nad+ and nadp+. dietary deficiency of nicotinic acid can lead to pellagra. humans can synthesize nicotinic acid that derived from tryptophan.
non-competitive inhibition.
非竞争性抑制
in non-competitive inhibition, inhibitor bind to a different domain of an enzyme, lowering the maximum velocity but with normal km.
nucleosides.
核苷
a nucleoside consists of a purine or pyrimidine base linked to a pentose.
nucleotides.
核苷酸
a nucleotide is a phosphate ester of a nucleoside on 3’- or 5’-carbon of ribose. phosphorylation on 5’-carbon of ribose is the one most commonly esterified forms.
okazaki fragment.
冈崎片段
the short discontinuous segments, which later are joined by dna ligase, are called okazaki fragment after their discoverer.
oncogene.
癌基因
oncogenes are the genes capable of changing a normal cell into a transformed cells. many oncogenes encode abnormal signal transduction proteins involved in imitating the action of polypeptide growth factor.
operator.
操纵序列
the operator is a dna segment adjacent to the structural genes. the binding of the repressor to the operator prevents the transcription of these genes.
operon.
操纵子
a collection of prokaryotic structural genes that are present in a linear array and whose expression is controlled by the same regulatory region of the dna. this arrangement allows simple control over the expression of proteins that are all needed for a common job. it should be noted that an operon includes both operator and its associated structural genes.
osteomalacia.
软骨病
osteomalacia is caused by vitamin d deficiency in the adult, which leads to softening and weakening of bones.
oxidation.
氧化
when something is oxidized, something else must become reduced. with removal of an electron, ferrous is oxidized to ferric ion. so oxidation is a process with the loss of electrons.
oxidative phosphorylation.
氧化磷酸化
the process in which atp is formed as a result of the transfer of electrons from nadh or fadh2 to oxygen by a series of electron carriers.
parathyroid hormone (pth) .
甲状旁腺素
parathyroid hormone, an 84-amino acid-containing protein, is secreted by the chief cells of the parathyroid gland. the biological actions of pth are related to regulate calcium metabolism.
pentose phosphate pathway.
磷酸戊糖途径
an alternative route for the metabolism of glucose. the pathway generates both nadph for reductive syntheses and ribose residues for nucleotide biosynthesis.
peptide bond.
肽键
the bond that the a-carboxyl group of one amino acid is joined to the a-amino group of another amino acid by an amide bond in a polypeptide.
phospholipase c.
磷脂酶c
the activation of the phospholipase c is mediated by g protein. the active form of the enzyme catalyzes the hydrolysis of a membrane-bounded substrate to form two second messengers, diacylglyceride and inositol 1,4,5-triphosphate. diacylglyceride is capable of activating protein kinase c. inositol 1,4,5-triphosphate is effective for the release of calcium from intracellular calcium pool.
plasmid.
质粒
independently replicating circular pieces of dna whose natural function is to confer antibiotic resistance to the host cell.
platelet-derived growth factor.
血小板源生长因子
platelet-derived growth factor can stimulates growth of messenchymal and glial cells. also see “growth factor”.
point mutation.
点突变
it is cause by a single base change of dna gemone, which in turn results in a change in the messenger rna, a structural abnormality of gene expression.
polycistronic mrna.
多顺反子mrna
a single mrna that encodes more than one separately translated protein is referred to as a polycistronic mrna, which contains multiple independent translation start and stop codons for each cistron.
polypeptide chain.
多肽链
many amino acids joined by peptide bonds form a polypeptide chain, which has two different ends, i.e. n-terminal and c-terminal respectively.
polyribosome.
多核糖体
an mrna molecule with many ribosomes bound to it. many ribosomes can translate the same mrna simultaneously.
primary transcript.
初级转录本
primary transcript is the original unmodified rna product corresponding to a transcription unit.
primase.
引物酶
primase catalyzes polymerization of ribonucleoside 5’-triphosphates to form rna primers. the sequence of monomer addition is dictated by a template strand of dna and the chain lengths of primers are usually 10-50 nucleotides.
promoter.
启动子
promoter is a region of dna involved in binding of rna polymerase to initiate transcription.
prosthetic group.
辅基
many proteins require tightly bound, specific nonpolypeptide units for their biological activities. such a unit is called a prosthetic group.
protease.
蛋白酶
an enzyme that hydrolyzes the amide bonds in a protein. most proteases recognize a specific type of amino acid side chain and cleave the protein at specific points.
proto-oncogene.
原癌基因
normal cellular genes with the potential to become oncogenes are called proto-oncogenes or cellular oncogenes. these genes were conserved in a wide range of eukaryotic cells. the conserved sequences were important components of normal cells and their products are believed to play important roles in normal differentiation and other cellular process.
pyridoxal phosphate.
磷酸吡多醛
all transamination reactions require the coenzyme pyridoxal phosphate. the important functional groups of the coenzyme are the aldehyde group, which can form a schiff base with the a-amino group of an amino acid and facilitate transamination.
rate-limiting enzyme.
限速酶
enzymes catalyzing committed steps in unidirectional anabolic and catabolic pathways, which act as natural governors of metabolic flow and represent the most efficient regulatory intervention.
receptor.
受体
all of receptors are proteins that can selectively bind specific molecule and initiate their biologic effects.
recombinant dna.
重组dna
information exchanging by breaking and joining chromosomal dna. recombination can occur between genes with similar sequences or between genes with different sequences.
reduction.
还原
chemically, reduction is defined as the gain of electrons. nad+ is reduced to nadh. it follows that reduction is accompanied by oxidation of an electron donor.
replication.
复制
generation of a new copy of double-stranded dna from a parental dna molecule.
residue.
残基
in a polypeptide chain, an amino acid unit is called a residue.
respiratory chain.
呼吸链
exists in the mitochondria, consists of a number of redox carriers. the respiratory chain provides most of the energy captured in metabolism.
restriction endonuclease.
限制性内切核酸酶
the classes of endonucleases cut dna at specific dna sequences within the molecule.
reverse transcriptase.
反转录酶
an rna-directed dna polymerase in retroviruses; capable of making dna complementary to an rna.
reverse transcription.
反转录
rna-directed synthesis of dna, catalyzed by reverse transcriptase.
ribosomes.
核糖体
complex cytoplasmic particles each consisting of two ribonucleoprotein subunits. translation of mrna occurs on it.
ribozyme.
核酶
a class of rnas that meet all the classic criteria for definition as enzymes. these catalytic rnas catalyze highly specific hydrolysis of phosphodiester bonds in rnas and are important in the processing events involved in maturation of pre-mrna.
rickets.
佝偻病
vitamin d deficiency in childhood produces rickets characterized by low plasma calcium and phosphorus levels and by poorly mineralized bone with associated skeletal deformities.
rna editing.
rna 编辑
the information content of some mrna is altered following transcription by process other than rna splicing.
rna polymerase.
rna聚合酶
rna polymerase is an enzyme that synthesizes rna using a dna template.
rrna.
核蛋白体rrna
ribosomal rna. structural components of ribosomes. there are several discrete size classes of rrna, usually referred to by their sedimentation coefficients as 5s, 5.8s, 18s, and28s in eucaryotic cells.
s-adenosyl methionine, sam.
s腺苷蛋氨酸
sam is a major donor of one-carbon unit at the methyl oxidation state, which is formed from methyl-thf and homocysteine by a vitamin b12-dependent reaction.
salting out.
盐析
the solubility of the proteins is lowered at high salt concentrations, so-called the “salting out”. it can be used to fractionate proteins because the dependence of solubility on salt concentration differs from one protein to another.
salvage pathway.
补救合成途径
the pathways that purines and pyrimidines derived from nucleic acid catabolism react with prpp and form the corresponding ribonucleotides. corresponding deoxyribonucleotides are produced by reduction of the ribonucleoside diphosphates, using nadph as the reducing agent.
semiconservative replication.
半保留复制
dna replication follows a law called semiconservative replication, i.e., one of the strands of each daughter dna molecule is newly synthesized, whereas the other is passed on unchanged from the parent dna molecule.
sigma factor.
σ因子
sigma factor is the subunit of bacterial rna polymerase needed for initiation. it is the major influence on selection of binding sites (promoters).
signal transduction.
信号转导
the process by which an extracellular signal is amplified and converted to a cellular response. for example, growth factors act on the cell cycle and mitosis via transmembrane signal transduction.
snrna.
小核rna
small nuclear rna. they have roles in rna processing but are not directly involved in protein synthesis.
splicing.
剪接
splicing describes the removal of introns and joining of exons in rna; thus introns are spliced out, while exons are spliced together.
substrate.
底物
reagent in a catalytic reaction by an enzyme.
synthase.
合酶
a synthase is an enzyme that makes something but doesn’t directly require the hydrolysis of atp to do it.
synthetase.
合成酶
a synthetase requires the hydrolysis of atp to make the reaction go.
telomere.
端粒
specialized structure at the ends of chromosomes that allows replication of the extreme 5’ ends of the dna without loss of genetic information.
template strand.
模板链
the template strand, also known as the antisense strand, is one strand that the genetic information resides in the sequence of nucleotides in the double-stranded dna molecules. this is the strand of dna that is copied during nucleic acid synthesis.
terminator.
终止子
terminator is a sequence of dna , represented at the end of the transcript, that causes rna polymerase to terminate transcription.
thiamine pyrophosphate, tpp.
焦磷酸硫胺素
it is derived from the vitamin thiamine, which is required for decarboxylation of a-keto acids and also involved in some transfer reactions of aldehyde derivatives.
topoisomerase.
拓扑异构酶
enzymes that catalyze topologic changes of dna are called topoisomerases, which can relax or insert supercoils. topoisomer of dna can be interconverted only by cutting one or both dna strands and then rejoining them.
trans-acting factor.
反式作用因子
trans-acting factor is used to describe the effect of a product from one gene on the transcription of another gene.
transamination.
转氨基作用
the amino acid are degraded via reaction of transamination, in which the a-amino group is transferred to a acceptor a-ketoacid with production of the a-keto derivative of the amino acid.
transcription.
转录作用
the synthesis of rna using a dna template. rna polymerase catalyzes the synthesis and uses the antisense strand as a template.
transferrin.
运铁蛋白
transferrin carries two ferric ions and transfer them to cells having receptors for transferrin. association with transferrin diminishes the potential toxicity of free iron and directs iron to where it is required in the body.
translation.
翻译
the synthesis of protein directed by the nucleotides sequence of an mrna. translation occurs on ribosomes.
triglyceride.
甘油三酯
also called triacylglycerol. it is formed by glycerol molecule and three fatty acid chains, which attached through ester linkages.
trna.
转运rna
transfer rna. they serve as adaptor for the translation of the information in the sequence of nucleotides of the mrna into specific amino acids.
ubiquinone.
泛醌
a redox carrier presented in the respiratory chain, which is also called coenzyme q. it exists in mitochondria, linking the flavoproteins to cytochrome b.
uncouples.
解偶联
allow protons back into the mitochondria without making any atp.
upstream.
上游
upstream identifies sequence proceeding in the opposite direction from expression; for example, the bacterial promoter is upstream of the transcription unit, the initiation codon is upstream of coding region.
urea cycle.
尿素循环
the pathway that excess ammonia produced by deamination is excreted after conversion to urea is called urea cycle. since urea synthesis converts toxic ammonia to nontoxic urea, the defects in urea synthesis result in ammonia intoxication.
vectors.
载体
something that can be used to introduce recombinant dna into a host organism. an insert is the piece of dna that has been placed into the vector.
vitamin b12.
维生素b12
this vitamin is synthesized exclusively by microorganisms. in animals, it is conserved in the liver. the absorption of vitamin b12 in the intestine is mediated by receptor sites, i.e., intrinsic factor. in clinic, deficiency of vitamin b12 can lead to anemia.
vitamin d.
维生素d
cholesterol is the precursor of vitamin d. by various metabolic changes in the body, cholesterol is converted into calcitiol, which plays an essential role in the control of calcium and phosphorus metabolism.
zwitterion.
兼性离子
an amino acid exhibits dipolar ions (zwitterion) rather than un-ionized molecules at suitable ph. in the dipolar form of an amino acid, the amino group is protonated and the carboxyl group is dissociated so that a molecule has zero charge.
ρ factor.
ρ因子
rho factor is a protein involved in assisting e.coli rna polymerase to terminate transcription at certain (rho-dependent) sites.
实验心得体会
在真正投入到创新实验计划当中之前,我以为不会很难。因为课内实验我们也做了很多,只要做好预习工作,好好听老师的讲解,再加上自己多动脑筋,几乎没遇上什么比较大的困难,实验完成起来也比较快。各种各样的实验加起来,涉及的知识面很广,学到了很多,让自己对于这样的研究与实验工作也更加感兴趣。
但是真正开始创新实验计划时,发现我仿佛进入了一个新的空间。一切要从头学起,从最简单的做起。与高年级的学长比起来,自己的基本实验技能与专业知识少的可怜,面对那些精密的仪器与无数的文献资料,信心一下子被浇熄了大半。每天跟在学长后面做着清洗瓶子,到扫卫生,摘桑叶,诸如此类的体力活。貌似什么也学不到,看着学长学姐一言不发的熟练操作,却一点也摸不到头脑。 有时真的懊恼的有些想泄气,但幸亏老师常常与我们开会讨论,开导鼓励我们,他还时常有意无意地启发我们的安全防范意识。古语说的没错:耳濡目染。一天天下来,不知不觉当中,我们的实验技巧越来越熟练,对于一些仪器的基本操作也能单独上手,学长学姐很有耐心地一次次纠正我们犯下的或大或小的错误,并不厌其烦的叮嘱我们注意安全。
渐渐地我们可以单独完成一些比较系统全面的实验工作。但错误当然也是不可避免的,而且人往往要犯错之后才能明白如何不犯错和为什么不要犯下这样的错误。比如因为我们某一步的实验操作不规范,导致最后的实验结果不尽入人意,无法纳入最后的总结分析中,也就是说我们白忙活一场。其实这样的失败也未尝不是一件好事,通过它我们更加清晰地认识到这个实验步骤的原理、影响及具体细节。
重复这是整个实验过程中常做的一件事,面对规律性不强的实验结果,我们只有一次次反思,重新再来,如果一而再再而三的重复失败,我们就只得求助于学长学姐和老师们了,但是这样具体的操作细节中失误,非当事人又是无法完全了解的,还是需要我们自己一点一点的去摸索。
当然整个实验过程中最困难的还要数自行设计实验的具体步骤了,老师所能给的知识一个全面概括的指导意见,让我们不致发生方向性的失误。老师也给了我们一些相关的文献资料,但同样的道理,具体到某一方面我们还是要自己去搜索,筛选,概括。有时甚至要面对一些英文文献,仅凭我们已有的英文水平还过于单薄。困难就是让人来解决的。我们摸索前进,自己跑到机房查资料,下载翻译软件,制定实验方案,阅读大量晦涩难懂的文献,失败了就再来一次,总结后再勇往直前。困难一个接着一个,但既然选择了这条路,我们就要毅然决然的走下去,不管后面的路是沼泽泥泞还是荆棘丛生。
终于我们的实验数据慢慢变得有规律起来,面对棘手的麻烦我们也能镇定自若,实验的因素探索一个个完成,一点点接近于目标。回望之前,发现与取得的成绩,获得的知识相比,以前都算不了什么。
不得不承认,通过这项本科实践创新训练项目,我们学到了很多,得到了很多,有些是书本上永远也学不来的,有些仅靠我们自己摸索几乎为不可能的,有些仅凭我们自行监督是无法坚持下来的。
在这里要感谢关心爱护我们的老师,学长学姐还有同届同学以及学弟学妹,没有你们我们无法完成这项艰巨的工作。
生物化学教学总结
高一是中学生学习非常重要的时期,是培养兴趣、扎实基础,发展能力的关键阶段,这一阶段的起始教学直接影响高中三年的学习,因此,本学科的教学必须做到常常总结和反思,才能在不断提高教师的教学技能和思想觉悟的基础上,发展学生的认知水平与技能水平。随着期末的到来,一学期的教学工作也接近尾声了。回顾这学期本学科的教与学,虽然基本上按时地完成了教学计划,取得了一定的成果,但缺点和不足也是不容回避的,现将工作总结如下:
一、教学目标完成情况
在教学方面,本人平时做好了钻研教材、认真备课,不但备学生而且备教材备教法,根据教材内容及学生的实际,设计课的类型,拟定采用的教学方法,并对教学过程的程序及时间安排都作了详细的记录,认真写好教案。每一课都做到“有备而来”,每堂课都在课前做好充分的准备,课后及时对该课作出总结,写好教学反思,并认真按搜集每课书的知识要点,归纳成集。
在上课过程中,在了解学生原有知识与技能水平的基础上讲授重难点,组织好每一节的课堂教学,增强上课技能,提高教学质量。为了使课堂上的讲解线索清晰,层次分明,言简意赅,深入浅出,我在课堂上特别注意调动学生的积极性,加强师生互动,充分体现学生的主体性,让学生学得容易,学得轻松,学得愉快,让学生在教师的引导下主动地参与到学习中来。
此外,及时布置与批改作业、课后辅导、听课、评课等工作也同步进行,并借助各种学习渠道广泛收集课堂素材以形成比较完整的知识结构,一方面可以使学生学有所得,不断提高,另一方面也可以帮助自己不断提高自己的教学水平和思想觉悟,并顺利完成教育教学任务。
在教学成绩方面,依据本学科在开学初制定的教学计划,让学生掌握人体主要化学物质的组成、结构、性质和功能,熟悉人体物质代谢的主要过程及生理意义,了解生物化学与人体健康之间的密切关系,具备科学的思维方法以及理论联系实际的工作作风,具备良好的`人际交往、沟通能力和团队意识,认识到科学是一个过程,进而培养科学的世界观与人生观。经过一学期的学习,大多数学生基本上达到了最基本的教学目标,掌握了学习生物化学的方法,自学再生能力得到了某种程度的提高,但由于环境条件的制约,缺乏大环境的熏陶,学生的成绩还参差不齐,具体表现在少数后进生虽然知识上掌握了该学科的相关理论基础,但能力方面还有所欠缺,有待发展与提高,因此整体成绩提高得不快,有些甚至不尽人意,这有待今后工作中不断的探索、借鉴与完善。
二、教师自我发展情况
21世纪是生命科学的世纪,生物学知识日新月异,发展很快,随着课程改革的推进,对教师的素质要求更高。为了使教学工作有目的、有计划、有组织地开展,根据本校的实际条件和学生的实际情况,在充分了解学生的知识、能力基础上,按照学校的各项要求,立足现在,放眼未来,提高教师的教以利于学生的学,教师应在自己已有的水平上不断地进步和提高,才能跟上教育改革的步伐。因此,在教师的自我发展方面,学习新的理念是最基础的内容,也是一种不能中断的学习。
在备课过程中,我在熟悉教材的基础上,不断查阅资料,不断更新教学理念,并在教学中实施。为了赶上时代步伐,我在讲授教材内容的基础上,还经常上网查阅资料,了解现代生物学新成果、新观念。但由于初上讲台,教学技能与策略都不够熟练,所以这方面得虚心向老教师请教,取长补短的同时,根据自己的教学特点,形成自己独特的教学风格和特色。
三、存在的问题与反思
现在班级存在的问题是后进生的学习,没兴趣、听不懂、不想听是他们普遍表达的观点,如何培养后进生对本学科的学习兴趣,提高他们的成绩是耽误之急,也是一个长期的工作。要提高后进生的成绩,首先要解决他们心结,让他们意识到学习的重要性和必要性,使之对学习萌发兴趣。要通过各种途径激发他们的求知欲和上进心,让他们意识到学习并不是一项任务,也不是一件痛苦的事情。而是充满乐趣的,从而自觉的把身心投放到学习中去。这样,后进生的转化,就由原来的强制学习转化到自觉的求知上来。在此基础上,再教给他们学习的方法,提高他们的技能。并认真细致地做好查漏补缺工作。后进生通常存在很多知识断层,这些都是后进生转化过程中的拌脚石,在做好后进生的转化工作时,要特别注意给他们补缺,把他们以前学习的知识断层补充完整,这样,他们就会学得轻松,进步也快,兴趣和求知欲也会随之增加。
以上几点是我本学期在工作中的总结,有所得,有所不足。今后我定会在教学中不断改进,以适应教育改革的新浪潮,努力使学生的成绩在原有的基础上有更大的进步。
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