楼顶上的生物作文【一】
Dear Sir or Madam:
In my capacity as the chairman of Biochemistry and Molecular Biology Department, the School of Life Science, Nankai University, I deem it a pleasure to recommend Mr. Bruce Liu as a worthy candidate for graduate studies at the Department of Cell and Molecular Biology of your esteemed university.
Over the past four years, I delivered two important courses Genetics and Cell Engineering to the Mr. Liu‘s class and his performance was impressive. He is endowed with a strong curiosity in the quest for new knowledge. Before attending each class, he would make full preparations so that he could quickly assimilate what was being taught. Sometimes he could come up with some surprisingly thought-provocative questions and he had a habit of discussing important problems with me in great detail. During those discussions, he often brought with him valuable materials that he obtained from a large quantity of technical literature. Such an initiative enabled him to broaden his ken of knowledge extensively and to cultivate and significantly improve his ability in reading technical literature in English and to follow the latest scientific and technological development in the world. Therefore, even before he graduated, he had already distinguished himself from the rest of his classmates in his English proficiency. Furthermore, his indefatigable spirit of reading large amount of technical materials was not simply intended to secure high scores in his coursework, but more importantly, to satisfy his almost insatiable interest in biology.
Apart from this, I was also very impressed by Mr. Liu‘s hands-on ability in conducting experiments. For many complicated experiments, he undertook them with a rigorous and conscientious attitude and would always complete them satisfactorily. In dealing with crucial steps involved in the experiments, he tended to make bold hypotheses and conduct substantial observations, ultimately achieving remarkable results. All those testify to Mr. Liu‘s tremendous potential in academic research, especially in his analytical skills and in the execution of experimental procedures.
In addition to his scholastic aptitudes, Mr. Liu can be described as trustworthy in personality. His kind-hearted nature and his integrity have created many friends for him. By no means a bookworm, Mr. Liu took an active part in extracurricular activities in which he enhanced his group spirit and the sense of collectivism. His willingness to assist his classmates has brought him a very high reputation.
To summarize, Mr. Liu has been an outstanding student in our department and he is fully qualified to undertake high-level studies in a more challenging environment. His excellent qualities will undoubtedly facilitate him in achieving satisfactory results in his future academic pursuit and in his career.
Yours Sincerely
Professor and Chairman of Biochemistry and Molecular Biology Department
Nankai University
楼顶上的生物作文【二】
分布：植物体各处。
特点：生活的薄壁细胞，较大，近于等径。细胞壁由纤维素与果胶质组成，细内
液泡较大，原生质较少，细胞器排列疏松，具明显的胞间隙。
分类：同化组织（细胞中含叶绿体，营光合作用，多数分布在叶，茎的表层部位）
通气组织（细胞间隙大，多见于水生物）
吸收组织（根毛细胞）
贮藏组织（细胞较大，细胞内储存大量后含物，淀粉）
楼顶上的生物作文【三】
1、细胞壁的形成：由原生质体分泌的物质形成，在细胞分裂过程中已形成。成分：主要是纤维素、果胶质，还有非纤维素的多糖、水和蛋白质等其他物质。
2、细胞壁的功能：维持细胞形状，保护原生质体，影响植物的吸收、保护、支持、蒸腾、物质运输、分泌等要的生理活动。
3、细胞壁的结构:
楼顶上的生物作文【四】
生物课是我在小学没有接触过的科目，生物老师把生物课的内容讲的既新鲜又生动，让我对生物产生的好奇心。
生物老师首先讲了生物的定义，（有生命现象的物体）及生物的特征（进行呼吸，获得氧气，排出二氧化碳，需要营养生存和繁殖，生物对外界刺激反应，应刺激，排废物，新陈代谢）
生物老师滔滔不绝生动的课堂给我带来对生物界的惊喜，物种种类大约有200万种，其中，植物40万种，动物150万种，地球真是个大家庭。
应刺激特征，以含羞草为例，含羞草身上有一个液体袋囊，袋囊里充满了液体，当有在界碰触它的叶子时，叶子就会合拢，这一现象，叫应刺激特征。
还有一种非生物类型，以珊瑚为例，珊瑚是有珊瑚虫一代代死去的外壳经年深日久的堆积在一起，慢慢形成了千资百态的珊瑚，珊瑚的聚多形成了珊瑚礁，珊瑚礁是珊瑚虫和藻类植物生活场地，藻类植物给珊瑚虫提供了氧气，珊瑚堆积的越高，附在珊瑚的藻类植物所的到的阳光和氧气越充足，藻类就越茂盛，这就说明珊瑚喜欢生活在温暖的浅水区，和藻类植物互为利用。
神奇的大自然里创造出形形色色的生物，它们的奥妙等待我们去探索，去解答。
楼顶上的生物作文【五】
组 织：指植物体内许多形态结构、机理相同的细胞，在器官发育中有相同来
源，且相互密切联系共同完成一种或几种生理功能的细胞群。
器 官：由各种不同的组织组合在一起形成植物的器官。
简单组织：由一种类型细胞构成的组织。
复合组织：由多种类型细胞构成的组织。
楼顶上的生物作文【六】
组 织：指植物体内许多形态结构、机理相同的细胞，在器官发育中有相同来
源，且相互密切联系共同完成一种或几种生理功能的细胞群。
器 官：由各种不同的组织组合在一起形成植物的器官。
简单组织：由一种类型细胞构成的组织。
复合组织：由多种类型细胞构成的组织。
楼顶上的生物作文【七】
我们迎来了第一次实验课。在周三老师说时，大部分同学都已经迫不及待的想去上生物实验课了。
周四到了，同学们迫不及待的心情被激发了一般，纷纷跑了出去，只有几个同学知道还有眼睛保健操没有做。这时，一个人大喊：“还有眼睛保健操没有做！“大家纷纷又回到座位上。有几个同学看着我的旁边，哦，原来是李冉喊得，大家看看李冉又回到座位上，好像在说这次多亏了李冉提醒，否则，我们班就被扣分了。
第三节课了，同学们飞快的跑到了生物实验室。刚到实验室时，同学们兴奋着：“我们想坐哪儿就坐哪儿！”但老师一声令下：“按班里的位置坐。”“啊，旁边的人又没有变啊！”我在心里说。
老师发下来了玻片，一个是人血图片。一想到人血图片，我不禁打了个寒颤。我和同桌迅速按书上说的完成了对光。第一次，我们观察，李冉说：“我看到了两个细长的东西。”我也去看时我发现我能控制这个东西，我向左它向左，我向右它向右。我仔细一看这个东西，不是生物而是我的眼睫毛。哈哈哈，我在哪儿大笑。到后来，张乐涛说：“我看到了。”同学们都议论着说：“他为什么这么快？”好多同学都议论纷纷。
接下来，好多同学都说：“我也完成了。”我和同桌却什么也没有看见，我们去请教已经完成的，但依然什么也没有完成。
楼顶上的生物作文【八】
形成：细胞停止伸长生长以后时产生。分内层、中层和外层。
特点：由纤维素和其他非半纤维素物质如木质组成。
功能：机械支持。
