Chemistry is the study of the behavior and composition of matter. All foods are
made up of chemical substance which undergoes chemical changes when cooking 1.______
in an oven or digested within the body. The cooking of meat and vegetables induce 2.______
chemical changes, making it more delicious; similarly the leavening action of 3.______
baking powder is a straightforward chemical change, as is the conversion of
starch into sweet sugars by digestion.
Cookery is a science requiring a knowledge of chemistry. 4.______
This is evident from the variety of cooking products and food additives available
as cooking oils, fats, colorings, sweeteners, tenderizers, flavorings, screaming
agents, preservatives, etc. Each is carefully prepared before painstaking 5.______
research.
It is therefore essential for trained cookers to understand 6.______
chemical science in order to appreciate the chemistry nature of foods 7.______
and the changes achieving on cooking. Homeworkers should also 8.______
know cleansing agents and textiles used in the home and how the latter 9.______
responds to the effects of heat, light, water, and chemical cleansing agents. 10.______
You work as a network technician at Company. Please study the exhibit carefully. In this Company wireless network, the LAP (lightweight access point) attempts to register to a WLC (Wireless LAN Controller). What kind of message is transmitted?()
What does the world bank study show?
There was ______ time when he wanted to study a second foreign language to find ______ better job.
Test 15 Study the following two pictures carefully and write an essay of about 200 words.
Your essay should meet the requirements below:
1)Describe the pictures.
2)Deduce the purpose of the painter of the pictures.
3)Suggest counter-measures.
Scientists study the development of expertise in different areas so that their findings can help children in becoming experts in these and other areas.
[A] The work builds on a study published last year by Shinya Yamanaka of Kyoto University in Japan, which showed that mouse tail cells could be transformed into ES-like cells by inserting four genes (Science Now, 3 July 2006).Those genes are normally switched off after embryonic cells differentiate into the various cell types. In June this year, Yamanaka and another group reported that the cells were truly pluripotent, meaning that they had the potential to grow into any tissue in the body (Science Now, 6 June).
[B] In the new work, Yamanaka and his colleagues used a retrovirus to ferry into adult cells the same four genes they had previously used to reprogram mouse cells: OCT3/4, SOX2, KLF4, and c-MYC. They reprogrammed cells taken from the facial skin of a 36-year-old woman and from connective tissue from a 69-year-old man. Roughly one iPS cell line was produced for every 5,000 cells the researchers treated using the technique, an efficiency that enabled them to produce several cell lines from each experiment.
[C] Now the race to repeat the feat in human cells has ended in a tie: Two groups report today that they have reprogrammed human skin cells into so-called induced pluripotent cells (iPSs). In a paper published online in Cell, Yamanaka and his colleagues show that their mouse technique works with human cells as well. And in a paper published online in Science, James Thomson of the University of Wisconsin, Madison, and his colleagues report success in reprogramming human cells, again by inserting just four genes, two of which are different from those Yamanaka uses.
[D] Once the kinks are worked out, “the whole field is going to completely change,” says stem cell researcher Jose Cibelli of Michigan State University in East Lansing. “People working on ethics will have to find something new to worry about.”
[E] Thomson’s team started from scratch, identifying its own list of 14 candidate reprogramming genes. Like Yamanaka’s group, the team used a systematic process of elimination to identify four factors: OCT3 and SOX2, as Yamanaka used, and two different genes, NANOG and LIN28. The group reprogrammed cells from fetal skin and from the foreskin of a newborn boy. The researchers were able to transform about one in 10,000 cells, less than Yamanaka’s technique achieved, Thomson says, but still enough to create several cell lines from a single experiment.
[F] Scientists have managed to reprogram human skin cells directly into cells that look and act like embryonic stem (ES) cells. The technique makes it possible to generate patient-specific stem cells to study or treat disease without using embryos or oocytes—and therefore could bypass the ethical debates that have plagued the field. “This is like an earthquake for both the science and politics of stem cell research,” says Jesse Reynolds, policy analyst for the Center for Genetics and Society in Oakland, California.
[G] Although promising, both techniques share a downside. The retroviruses used to insert the genes could cause tumors in tissues grown from the cells. The crucial next step, everyone agrees, is to find a way to reprogram cells by switching on the genes rather than inserting new copies. The field is moving quickly toward that goal, says stem cell researcher Douglas Melton of Harvard University. “It is not hard to imagine a time when you could add small molecules that would tickle the same networks as these genes” and produce reprogrammed cells without genetic alterations, he says.
(此文选自Science2007年刊)
Order:
Majored Finance An increase in students (11)to study economics at university is being attributed to (归因于)the global economic crisis awakening a public thirst for knowledge about how the(12)system works. Applications for degree courses beginning this autumn were up by 15% this January, according to UCAS, the Universities and Colleges Admissions Service. A(13)for the Royal Economic Society said applications to do economics at A-level were also up. Professor John Beath, the president of the society and a leading lecturer at St Andrews University, said his first-year lectures—which are open to students from all departments—were (14)crowds of 400, rather than the usual 250. "There are a large number of students who are not (15)majors, who would like to learn something about it. One of the things I have done this year is to relate my teaching to contemporary (16)in a way that one hasn't traditionally done," he added. University applications rose 7% last year. But there were rises above average in several subjects. Nursing saw a 15% jump, with people's renewed interest in (17)in the public sector (部门) ,which are seen as more secure in economic crisis. A recent study showed almost two thirds of parents (18)schools should do more to teach pupils about financial matters, and almost half said their children had asked them what was going on, although a (19)of parents felt they did not understand it themselves well enough to explain. Zack Hocking, the head of child trust funds, said: "It's possible that one good thing to(20)from the downturn will be a generation that's financially wiser and better equipped to manage their money through times of economic uncertainty." 17.()
Exhibit: You work as a network technician. Please study the exhibit carefully. In this wireless network, theLAP (lightweight access point) attempts to register to a WLC (Wireless LAN Controller). What kindof message is transmitted?()
(),is the study of how words combine to form sentences and the rules which govern the formation of sentences.