单选题染色体结构变异中的缺失和重复在染色体配对中都形成环(瘤)，但这两种变异形成的环所涉及的染色体是不同的，其中缺失环涉及______。 A．缺失染色体 B．部分重复染色体 C．正常染色体 D．缺失和正常染色体交换

单选题下表是T4噬菌体5个表型相似的突变体的互补实验结果(+、-分别表示能和不能互补)，试根据结果判断他们分属于几个顺反子?______ 1 2 3 4 5 1 - + + + + 2 - + - + 3 - + - 4 - + 5 - A．2 B．3 C．4 D．5

单选题如果在第三代中雄性1与雌性4交配，它们的第一个子代是淡黄毛的概率是______

单选题纯种芦花雄鸡和非芦花母鸡交配，得到子一代。子一代个体互相交配，问子二代的芦花性状与性别的关系是______。

单选题细胞质基因的分离和重组的过程______。 A.类似于有丝分裂 B.类似于减数分裂 C.类似于细菌的二分分裂方式 D.没有规律，具有随机性

单选题如果一个平衡的群体中有4%个体表现出由单基因控制的隐性性状，那么两个没有表现出这个性状的个体的后代出现该隐性性状的比例为( )。

单选题某个体发生了性细胞的隐性突变，在后代中，突变性状的表现和出现突变纯合体是______。 A．第一代表现，第二代纯合 B．第二代表现，第二代纯合 C．第一代表现，第一代纯合 D．第二代表现，第三代纯合

单选题22，原核启动子在-35和-10处有两个中心，-10处的序列对DNA解链有重要作用，此处 a．富A-T； b．富G-C； c．A-T/G-C各半。

单选题真核细胞液中的mRNA通常是 a．monocistronic； b．polycistronic； C．intercistronic。

单选题在一个链霉素抗性的Hfr菌株中，已知A位点比B位点先转移，而Strs位点最后转移，用菌株HfrA+B+Strs与F-A-B-StrR菌株接合，经一定时间用搅拌器中断接合，添加链霉素，然后分析活菌的基因型，各种基因型如下：A-B-=80% A+B+=10% A+B-=50% A-B+=5%，从这些资料看，A和B之间的重组率应是______ A.10% B.20% C.50% D.33.3% E.上述答案均不对

单选题一条雌鲫鱼一年内能繁殖约3000余条幼鱼，但能够生存下来并发育成熟的却很少，按照达尔文进化观点，这个实例说明了( )。

单选题在一个隔离的岛上住着5800个人，其中2800人是男性。有196个男性患有红绿色盲。该色盲是由于伴X隐性突变因子(r)造成的。该色盲不影响个体的健康。在该岛上至少有一个女性患此种色盲的可能性是多少?

单选题It's obvious that humans are fundamentally different from other animal species. It's not so easy, though, to identify the traits that make human beings so special. Scientists realized long ago that other animals make tools, play jokes and even have a sense of justice and altruism—all things we once thought were unique to our species. Now a paper in the journal Current Biology has added another behavior to the list of what other animals share with us—and this one isn't quite so charming. After years of field observations in Uganda's Kibale National Park, John Mitani of the University of Michigan and several colleagues have concluded that chimps wage war to conquer new territory. "We already knew that chimps kill each other," says Mitani. "We've known this for a long time." What scientists didn't know for certain, at least in cases in which groups of chimps banded together to kill others, was why. One hypothesis, advanced more than a decade ago by anthropologist Richard Wrangham, was the idea of territorial conquest; circumstantial evidence from both Gombe and Mahale national parks in Tanzania bolstered the theory. In Mahale, for example, male members of one group mysteriously vanished, and another group then expanded into what had been their land. In Gombe, an existing group dissolved into civil war, resulting in killings and land takeovers. What's especially chilling about the observation is that the murder rate appears to be so high. The anthropologists couldn't be certain of how big a band the victims belonged to because they weren't used to a human presence and thus couldn't be accurately counted. But even a conservative estimate suggests that the death rate is significantly higher than you would see in war between human hunter-gatherer groups. Mitani isn't oblivious to the lesson some people might draw from the study. "Invariably, some will take this as evidence that the roots of aggression run very deep," he says, and therefore conclude that war is our evolutionary destiny. "Even if that were true," says Mitani, "we operate by a moral code that chimps don't have." Apart from that, he points out, the Pan troglodytes chimps he studies are one of two subspecies. The other is called Pan paniscus, also known as bonobos, and, says Mitani, "the latter, as far as we know, aren't nearly as aggressive with respect to intergroup relations. Yet they're equally close to us." That means that if we're wired for warfare, we're wired for peace too. Ultimately, the route we choose is still up to us.

单选题小鼠中，黑毛由常染色体隐性基因决定。两个正常毛色的小鼠交配，产生了一个黑色雄鼠，该黑色雄鼠与一个正常毛色雌鼠再进行兄妹间交配，那么所产生的第一个小鼠是黑毛的概率是(假设没发生突变)______

单选题苯丙酮尿症是一种隐性纯合的严重的代谢缺陷病症，基因位于常染色体上。如果两个正常的双亲，生了一个患病的女儿，一个正常表型的儿子，那么儿子是此病基因携带者的概率是______

单选题一个表型正常的人，其舅父患某种常染色体隐性遗传病，他如果和表型正常的姨表妹结婚，后代中患该病的风险是______。

单选题生物进化的内在因素是( )。

单选题A very important world problem, if not the most serious of all the great world problems which affect us at the moment, is the increasing number of people who actually inhabit this planet. The limited amount of land and land resources will soon be unable to support the huge population if it continues to grow at its present rate. In an early survey conducted in 1888, a billion and a half people inhabited the earth. Now, the population exceeds five billion and is growing fast--by the staggering figure of 90 million in 1988 alone. This means that the world must accommodate a new population roughly equal to that of the United States and Canada every three years! Even though the rate of growth has begun to slow down, most experts believe the population size will still pass eight billion during the next 50 years. So why is this huge increase in population taking place? It is really due to the spread of the knowledge and practice of what is becoming known as "Death Control". You have no doubt heard of the term "Birth Control"--" Death Control" is something rather different. It recognizes the work of the doctors and scientists who now keep alive people who, not very long ago, would have died of a variety of then incurable diseases. Through a wide variety of technological innovations that include farming methods and sanitation, as well as the control of these deadly diseases, we have found ways to reduce the rate at which we die--creating a population explosion. We used to think that reaching seventy years old was a remarkable achievement, but now eighty or even ninety is becoming recognized as the normal life-span for humans. In a sense, this represents a tremendous achievement for our species. Biologically this is the very definition of success and we have undoubtedly become the dominant animal on the planet. However, this success is the very cause of the greatest threat to mankind. Man is constantly destroying the very resources which keep him alive. He is destroying the balance of nature which regulates climate and the atmosphere, produces and maintains healthy soils, provides food from the seas, etc. In short, by only considering our needs of today, we are ensuring there will be no tomorrow. An understanding of man's effect on the balance of nature is crucial to be able to find the appropriate remedial action. It is a very common belief that the problems of the population explosion are caused mainly by poor people living in poor countries who do not know enough to limit their reproduction. This is not true. The actual number of people in an area is not as important as the effect they have on nature. Developing countries do have an effect on their environment, but it is the populations of richer countries that have a far greater impact on the earth as a whole. The birth of a baby in, for example, Japan, imposes more than a hundred times the amount of stress on the world's resources as a baby in India. Most people in India do not grow up to own cars or air-conditioners--nor do they eat the huge amount of meat and fish that the Japanese child does. Their life-styles do not require vast quantities of minerals and energy. Also, they are aware of the requirements of the land around them and try to put something back into nature to replace what they take out. For example, tropical forests are known to be essential to the balance of nature yet we are destroying them at an incredible rate. They are being cleared not to benefit the natives of that country, but to satisfy the needs of richer countries. Central American forests are being destroyed for pastureland to make pet food in the United States cheaper; in Papua New Guinea, forests are destroyed to supply cheaper cardboard packaging for Japanese electronic products; in Burma and Thailand, forests have been destroyed to produce more attractive furniture in Singapore and Japan. Therefore, a rich person living thousands of miles away may cause more tropical forest destruction than a poor person living in the forest itself. In short then, it is everybody's duty to safeguard the future of mankind--not only through population control, but by being more aware of the effect his actions have on nature. Nature is both fragile and powerful. It is very easily destroyed; on the other hand, it can so easily destroy its most aggressive enemy--man.

单选题Griffith发现，在活的无毒菌液中加入死的有毒性细菌然后感染家鼠，结果家鼠很快死亡，并释放出大量的有毒性细菌，那么细菌经历了何种过程才有此现象?______ A.转导 B.易位 C.转化 D.接合 E.衰退

单选题假如一个性状呈数量遗传，但估算的遗传力为0，那么下面这些结论中哪一个是正确的?( )