When a mutation occure, it cannot reverse to wild type.

A、a mutation that causes the overexpression of a DNA repair gene

B、a mutation that causes telomerase to have reduced expression in somatic cells

C、a deleterious mutation in one copy of a tumor-suppressor gene

D、a deletion that removes one copy of an oncogene

E、an extra X chromosome from the mother

请将以下国际法专业文献中的术语与段落翻译为中文。(上海交大2006年研) A loan syndication occurs when several lenders join together to make a loan to a single borrower on the basis of the same loan contract． Each bank has an obligation to make loans to the borrower in accordance with its commitment． If one bank fails to fund according to its respective commitment，the other banks ale not obliged to fund their pro—rata shares of the commitment．

A．1.？Cancer cells have a reduced dependence on signals from other cells for their survival, growth, and division. 2.？Cancer cells can survive levels of stress and internal derangement that would cause normal cells to kill themselves by apoptosis.

B．3.？Unlike most normal human cells, cancer cells can often proliferate indefinitely.？4. Most cancer cells are genetically unstable,with a greatly increased mutation rate and an abnormal number of chromosomes.

C．5. Cancer cells are abnormally invasive,at least partly because they often lack certain cell adhesion molecules, such as cadherins, that help hold normal cells in their proper plac

E．？6. Cancer cells are abnormally avid for nutrients, which they use to generate much of their ATP by glycolysis in the cell cytosol.

D．7. Cancer cells can survive and proliferate in abnormal locations, whereas most normal cells die when misplace

D．？8. As cancer cells evolve,they secrete signals that influence the behavior of cells in the surrounding connective tissue,thereby modifying the tumor’s microenvironment.

within a population influences their abilities to survive and reproduce in an environment. The differences in individuals is a result of their genetic inheritance from their parents. In a population, any characteristic which blocks reproduction success tends to decrease generation by generation. In time, the ill-adapted die out. On the other hand,the individuals who do survive and reproduce will tend to produce offspring which are better adapted to the environment. Natural selection tends to promote adaptations that will increase the organism's ability to survive in an environment.

Natural selection can serve to stabilize a population if the new traits, called mutations, are eliminated when they appear because they are not as well-adapted to the environment. The opposite effect is obtained when a new trait is introduced which allows individuals to adapt better over time, the species will change as this mutation becomes more widespread in the population. In human beings, increased brain size helped individuals to adapt better, and so brain size increased gradually in the species. Changes in the overall genetic makeup of a population are normal when there are environmental changes, especially sever environmental disruptions. Specialized adaptations to specific environments can lead, over time, to the development of subpopulation of individuals, ones who are better adapted to particular soil conditions food sources and so on. Given enough time, these subpopulations may develop into separate species, such as zebras and horses, living in distinct environments and not interbreeding.

Individuals in a population differ from one another because______.

A．they have different success generation by generation

B．they are ill-adapted and eventually die out

C．they have different genetic inheritances

D．they want to survive and reproduce successfully

es Darwin published The Origin of Species in 1859, the first edition sold out overnight. His revolutionary theory of evolution was of interest not only to his fellow scientists, but to great numbers of ordinary people, who avidly read The Origin and argued over the details of the theory. Today, public interest in biology is even greater. When a previously unknown Scottish biologist cloned the first mammal, a sheep, in February of 1997, the story made front-page headlines all over the world and sharply increased the value of biotechnology stocks overnight. Biology is a discipline in full flower. Biologists now have the capacity to understand the workings and the interactions of organisms and at the cellular level—to alter them, almost at will. Biologists have bred new crops, discovered the frailties and strengths of precious ecosystems, developed new treatments for diseases, and begun to solve many puzzles of the human mind. Spectacular as these developments are, they are a mixed blessing for instructors and their students. The sheer number of facts can be overwhelming. How, for example, can we remember the difference between a missense mutation and a nonsense mutation？ Between a Plasmodia slime mold and a cellular slime mold？ And, more importantly, why should we care？ Yet, to make even the simplest decisions in the 21st century you will need to understand how science works and, at least, the bare basics of biology. If you are sick, should you take an antibiotic？ If one of your parents has a genetic disease, should you be tested for the disease-causing allele？ If the vacant lot down the road is to be turned into a playing field, should the creek that runs through it be preserved？ Is there any harm in running the creek through an underground, concrete culvert？ The answers to all of these questions and hundreds of others depend on the ability to understand and evaluate scientific arguments. The greatest barrier to understanding science is the common misperception that science is inaccessible to ordinary folks. We know that it is accessible. Its about asking questions, getting a partial answer, and then asking further questions. Now get ready to answer the questions. You may use your notes to help you answer. 29. What is the main purpose of the talk？ 30. The professor mentions two great figures in the field of biology. What are their common attributes in the professors viewpoint？ 31. What is the general style. of this professors talk？ 32. According to the professor, which is true about the role of biology in peoples life？ 33. What does the professor mean when he says this？ Professor We know that it is accessible. Its about asking questions, getting a partial answer, and then asking further questions. 34. Why does the professor pose so many questions to the students in this beginning class？Narrator Listen to part of a lecture in a biology class. Now get ready to answer the questions. You may use your notes to help you answer.

What is the main purpose of the talk？

A．To review for an upcoming test.

B．To review material from an earlier lecture.

C．To go over a homework assignment.

D．To introduce points related to a new course.

in such sound combinations as /bi;p/, /geip/ and /su;p/, the voiceless stop /p/, occurring in the final position, is unaspirated, i.e. pronounce withheld to some extent.()

The name of a mass wasting process is a reflection of

A．the area in which the movement occurs

B．the material that is moved and the way it moves

C．the rate of movement relative to other processes

D．the mass and volume of the material involved

根据材料请回答 31～35

Natural Selection

Natural selection describes the biological process in which the differences of individu-als within a population influence their abilities to survive and reproduce in an environment.The differences in individuals are a result of their genetic inheritance from their parents.In a population, any characteristic which blocks reproduction tends to decrease generation by generation.In time, the ill-adapted die out.On the other hand, the individuals who do survive and reproduce will tend to produce offspring(后代which are better adapted to the environment.Natural selection tends to promote adaptations that will increase the organ- ism's(生物体)ability to survive in an environment.

Natural selection can serve to stabilize a population if the new traits, called mutations (突变), are eliminated when they appear because they are not as well-adapted to the envi-ronment.The opposite effect is' obtained when a new trait is introduced which allows indi-viduals to adapt better over time, the species will change as this mutation becomes more widespread in the population.In human beings, increased brain size helped individuals to adapt better; and so brain size increased gradually in the species.Changes in the overall genetic makeup of a population are normal when there are environmental changes, espe-cially severe environmental disruptions.Specialized adaptations to specific environments can lead, over time, to the development of subpopulation of individuals, who are better a- dapted to particular soil conditions, food sources and so on.Given enough time, these subpopulations may develop into separate species, such as zebras(斑马)and horses, living in distinct environments and not interbreeding.

第 31 题 Individuals in a population differ from one another because__________.

A．they have different success generation by generation

B．they are ill-adapted and eventually die out

C．they have different genetic inheritances

D．they want to survive and reproduce successfully

突变(mutation)