生物学如何造福人类英语作文【一】
横切面为平行双层膜结构，两层膜之间有空腔。分为光面内质网、糙面内质网。
生物学如何造福人类英语作文【二】
How to prevent the H7N9?
As is well known,the A flu is spreading throught our country. However, if we negnect it, the deadly H7N9 may cause more infectors,or even more deaths. So what is the most important is that we should take some effective measures to prevent it.They can be listed as follows.
Firstly,it is necessary for you to realize the Avian flu can be prevented if you develop good living habits. For example,you shouldn’t forget to wash your hands before meals.Besides,don’t spit everywhere and try to cover your mouth or nose with paper or hankerchiefs when you have to cough or sneeze.What’s more, remember to wear the mouth-cover if you have to go to the public places, such as the crowded cinemas,supermarkets, buses,where the A flu may spread easily.
Secondly,of course, taking exercise more often and taking good sleep to build your body are wise choices for you to reduce the risk of being infected.
Last but not the least, if you are unlucky to be infected with the slight flu cold, try to stay at home,and take some medicine. Do pay attention to your daily body temperature. If you have a high fever, go to the hospital without delay for further treatment. Make sure you are not expected to come back to school before the cold or flu is cured.
Only by doing like this can you prevent or defeat the A flu in the end.
生物学如何造福人类英语作文【三】
1、分生组织的概念：指植物体内保留的具有持久分裂能力的组织。
2、分生组织组成细胞的特点：细胞壁薄、体积小、原生质浓厚、细胞核大、液泡不明显。
3、分生组织的类型：
按位置分：
1）顶端分生组织分布于根、茎顶端形成初生植物体。
2）侧生分生组织分布于双子叶植物和裸子植物根、茎侧面形成植物体的次生结构。
3）居间分生组织位于植物顶端分生组织被成熟组织隔离而保留下来的部分。
按来源和性质分：
1）原生分生组织直接由植物胚胎里的细胞分裂保留下来的组织。
2）初生分生组织由原分生组织衍生细胞组成，已出现了分化，仍具有分裂能力。
3）次生分生组织由成熟组织经反分化成为具分裂能力的细胞。分为：维管形成层和木栓形成层。
4、组织的形成：成熟组织和非分生组织分生组织衍生的大部分细胞，逐渐丧失分裂能力，进一步生长和分化，形成的其它各种组织。
生物学如何造福人类英语作文【四】
功能： ① 调节物质进出原生质体；
② 协调细胞壁物质的合成和组装；
③ 进行植物激素和与细胞生长、分化有关的环境信号的转导。
流动镶嵌模型突出了膜的流动性和不对称性，认为细胞膜由流动的脂双层和嵌在其中的蛋白质组成。磷脂分子以疏水性尾部相对，极性头部朝向水相组成生物膜骨架，蛋白质或嵌在脂双层表面，或嵌在其内部，或横跨整个脂双层，表现出分布的不对称性。
