显微镜是生物实验中最常用的观察细胞的仪器，请回答下列有关实验的问题：(1)在观察洋葱鳞片叶的表皮细胞时，怎样区别显微镜视野中的气泡和细胞？_____________。(2)如果在视野-七年级生物

更多内容推荐

• 用糖拌西红柿，一段时间后，盘中会出现一些液体，主要原因是西红柿细胞的细胞液浓度[]A．大于外界溶液浓度，细胞吸水B．小于外界溶液浓度，细胞吸水C．大于外界溶液浓度，细胞失-八年级生物
• 在植物细胞结构中，具有支持作用的结构是[]A．液泡B．细胞质C．细胞膜D．细胞壁-七年级生物
• 将名词与相应的功能对应起来。1．细胞膜a．内有细胞液2．叶绿体b．控制物质进出3．分生组织c．运输水和无机盐4．输导组织d．分裂能力5．细胞核e．保护和支持细胞6．细胞壁f．遗传信息库7-七年级生物
• 阅读理解。 The students in America usually begin high school at the age of 13 or 14. Some leave at the ag
• 小华用薄刀片从一小茎切下一极薄的茎的样品制成玻片标本，则小华制取的是[]A．切片B．涂片C．装片D．无法判断-七年级生物
• 阅读理解。 Soon computers and other machines (机器) will be able to remember you by looking at your eyes! T
• 存在于细胞质中，与呼吸作用有关，为生命活动提供能量的结构是[]A．细胞质B．细胞核C．线粒体D．叶绿体-七年级生物
• 水稻叶肉细胞中的能量转换器的[]A．线粒体B．叶绿体C．线粒体和叶绿体D．液泡-八年级生物
• 完形填空。 How can you think in English? I think the best way is to practise as what a football player 1
• 读短文，用所给动词的适当形式填空。 The only language that seems easy to learn is the mother tongue. We should remembe
• 在制作洋葱表皮细胞临时装片时，错误的操作是[]A．将盖玻片的一边先接触水滴，再快速地盖上B．将盖玻片的一边先接触水滴，再缓慢地盖上C．在载玻片中央先滴一滴清水D．将碘液滴在-七年级生物
• 西瓜之所以甘甜可口，主要是因为西瓜的细胞质中含有大量的糖分。[]-七年级生物
• 阅读理解。 Whatwilltheweatherbelike?Somepeoplesaytheycanknowwhattheweatherwillbelikefrombirds.Whentheysee
• 图为植物叶肉细胞结构示意图，与图中序号相对应的结构名称不正确的是[]A．①表示叶绿体B．②表示液泡C．③表示细胞核D．④表示细胞膜-八年级生物
• 阅读理解。Lifts are very useful. Why?Think about a tall building. You work on the thirtieth fIoor. Maybe
• 阅读理解。 Isyourschoolbagtooheavytocarry? Thee-schoolbagswillhelpyou.Itissaidthate-schoolbagsaregoingtob
• 阅读下面短文，根据短文内容，完成表格中所缺的信息。Whatmakestheworldbecomesmaller?Someinventions.Itbegan inthe11thcentury,buti
• 阅读理解。 The English Fashion recently asked people about their wonderful ideas and plans about things t
• 阅读理解。 Every 30 seconds there is an earthquake. But don't worry because most are so weak that th
• 阅读理解。 Speaking is different among the four skills in learning English. The other three you can do al
• 细胞是物质、能量和信息的统一体，细胞的生活需要物质和能量。_____________能够将光能转变成化学能，___________能将有机物中的化学能释放出来，为细胞的生活提供动力，细胞-七年级生物
• 完形填空。 Most adults（成年人） once studied at school,had classes and did their homework every day.The same1
• 阅读理解。 The children at the top of the class succeed by knowing a few basic skills that others can eas
• 用所给动词的适当形式填空，必要时可加助动词或情态动词。 As school kids, we have many dreams. These dreams can be very big, such
• 烟草中含有对人体有害的尼古丁，它主要存在于烟草细胞的哪部分结构[]A．细胞核B．液泡C．细胞质D．细胞核-七年级生物
• 读短文，用所给动词的适当形式填空。 English is one of the most important subjects in middle schools. Almost everyone 1
• 构成一株油菜的基本单位是细胞，下列关于油菜的结构或组成物质由微观到宏观的排列顺序是[]A．基因、染色体、细胞核、细胞、组织、器官、系统、油菜B．基因、染色体、细胞核、细-八年级生物
• 请你推断，当植物细胞处于周围溶液浓度大的环境中时，液泡将[]A．缩小B．胀大C．消失D．正常-七年级生物
• 阅读理解。 Some school officials (官员) want to change the class time from 8:00 a. m. to 9:00a. m. Somestud
• ①细胞核A．为细胞生命活动提供能量②基因B．遗传信息库③DNAC．主要的遗传物质④线粒体D．有特定遗传功能的DNA片段⑤染色体E．由DNA和蛋白质组成-七年级生物
• 绿色植物进行光合作用的主要场所是[]A．叶绿体B．细胞核C．细胞膜D．液泡-七年级生物
• 下面是明明制作洋葱鳞片叶表皮细胞临时装片的操作步骤，操作顺序正确的是[]A．①②③④B．①③②④C．②①③④D．②①④③-八年级生物
• 综合填空。 There are four seasons in a year: spring, summer, fall and winter. In spring, the weather is w
• 阅读理解。 We are learning English, but how can we learn English well? A student can know a lot about Eng
• 完形填空。 There are differences1 boys' and girls' favorite subjects2 school. Many young3 like
• 阅读理解。 Let me tell you my first English class. It's very interesting. It's the first class
• 阅读理解。 The moon travels around the earth. The moon does this because gravity pulls it. Gravity is the
• 阅读理解。 In Japan many old people don't live with their children. They have no one to talk to. The
• 阅读理解。 Here is the survey of what the students in Mr Huang's class want to be:JobNumberReasondoc
• 阅读理解。 You prlbably know the food pyramid (金字塔) well enough. It is a food pyramid with horiaontal str
• 请在下列各序号后面的横线上填上恰当的结构名称，以完善细胞的概念图。①__________②__________③____________④_____________⑤_____________-七年级
• 缺词填空。 School education (教育) is very important and useful. Yet no one can (1) l______ everything at s
• 阅读理解。 Do you know why different animals or pests (昆虫) have their special colors? Colors in them can
• 阅读理解。 Round eyes, round head, round ears, round body! What is this lovely little animal?He looks lik
• 在显微镜下观察用碘液染色的洋葱表皮细胞，可看到染色最深的结构是[]A．细胞膜B．细胞质C．细胞核D．液泡-七年级生物
• 植物细胞中，被称为能量转换器的结构是[]A．细胞壁B．细胞核C．叶绿体D．细胞质-七年级生物
• 细胞进行光合作用，将太阳能转化为化学能的结构是[]A．细胞质B．线粒体C．叶绿体D．细胞核-七年级生物
• 完形填空。 According to a team of Dutch scientists, walking backward helps people think more clearly. The
• 我市某校生物活动小组的同学，在实习园地种植了经航天飞船搭载的太空番茄种子，在收获的番茄中有的味道较甜，有的味道稍酸，你知道这不同的果实中的甜味和酸味物质存在于下列-七年级生物
• 实验：观察植物细胞，请据下图回答问题。甲图是小明制作洋葱鳞片叶表皮细胞临时装片的过程图。(1)请写出正确的实验操作顺序_____________→_____________→_____________