Một gen rất ngắn được tổng hợp nhân tạo trong ống nghiệm có trình tự nucleotit như sau:         

Mạch I: (1) TAX ATG ATX ATT TXA AXT AAT TTX TAG GTA XAT (2)         

Mạch II: (1) ATG TAX TAG TAA AGT TGA TTA        AAG ATX XAT GTA (2)         

Gen này dịch mã trong ống nghiệm cho ra 1 chuỗi polipeptit chỉ gồm 5 acid amin. Hãy cho biết mạch nào được dùng làm khuôn để tổng hợp ra mARN và chiều sao mã (phiên mã) trên gen?  

Nếu mã gốc có đoạn: TAX ATG GGX GXT AAA... thì mARN tương ứng là:  

Một đoạn ADN có trình tự mạch mã gốc như sau 3’ ATG TAX GTA GXT…….. 5’. Hãy viết trình tự các nuclêôtit trong mARN sơ khai được tổng hợp từ gen trên:  

Quan sát hình mô tả cấu trúc của mARN, tARN, rARN và cho biết có bao nhiêu câu trả lời không đúng.  

(1) Các số (1), (2) và (3) trên hình vẽ tương ứng với các nội dung: liên kết hiđrô, côđon và anticôđon.

(2) Ở hình trên, tARN làm nhiệm vụ vận chuyển các axit amin và mang anticôđon 5’–UAX–3’.

(3) mARN có cấu trúc 1 mạch thẳng, làm khuôn cho quá trình phiên mã và mang bộ ba mở đầu là 3’– GUA–5’.

(4) tARN có 3 thùy tròn nên chỉ có thể mang tối đa 3 axit amin cho 1 lần tới riboxom.

(5) Axit amin gắn ở đầu 3'–OH của tARN này là Mêtiônin hoặc fMet.  

Nếu nội dung G + X của ARN trong tế bào E. coli là 30%, thì hàm lượng G + X của ADN sinh ra ARN đó là

ARN được tổng hợp từ mạch nào của gen?

Một gen rất ngắn được tổng hợp nhân tạo trong ống nghiệm có trình tự nucleotit như sau:         

Mạch I: (1) TAX ATG ATX ATT TXA AXT AAT TTX TAG GTA XAT (2)         

Mạch II: (1) ATG TAX TAG TAA AGT TGA TTA        AAG ATX XAT GTA (2)         

Gen này dịch mã trong ống nghiệm cho ra 1 chuỗi polipeptit chỉ gồm 5 acid amin. Hãy cho biết mạch nào được dùng làm khuôn để tổng hợp ra mARN và chiều sao mã (phiên mã) trên gen?  

Bộ ba đối mã (anticodon) của tARN vận chuyển acid amin metionin là

Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each of the numbered blanks from 24 to 28:

A child prodigy of four is receiving computer lessons at Brunei University, in London. Nicholas MacMahon is studying at university because he is too clever for school. A senior lecturer at the university, Valso Koshy, said that the boy was remarkably intelligent. Nicholas spoke fluently before he was one and by the time he was 18 months old, he was taking telephone (24) _______. This was soon followed by conversational French. These are the trademarks of a highly gifted child unusual but not unique. The strange thing about Nicholas is his reading - he taught himself to read before he could speak. Ms. Koshy, an expert (25) _______ gifted children, says Nicholas is quite exceptional. Yet “exceptional” underrates his amazing ability to read, almost from birth. “He was talking when he was one and we realized from the start that he could read,” his father said. “Soon after, he was correcting my spelling, words (26) _______ caterpillar. Now he (27) _______ insects by their Latin names.” The list of achievements is impressive, but frightening. A four-year-old who can (28) _______ a Boeing 747 from a DC 10, devours encyclopedias, read The Daily Telegraph and is well on the way to becoming a violin virtuoso is hardly normal.

Question 28:

Read the passage and mark A, B, C or D to indicate the correct answer to each of the blanks:

 In a small village in North Yorkshire, there is a big old farmhouse ______(31) three families live together. Alice and George and their three children, Joe and Pam and their two children, and Sue and her baby daughter. The adults divide up the work between them. George does the cooking, Joe and Sue do almost the housework. Pam looks after the shopping and ______(32) the repairs, and Alice takes care of the garden. Alice, George and Sue go out to work. Joe works at home ______(33) computer systems, and Pam, who is a painter, looks after the baby during the day. Two of the children go to school in the village, but the three oldest ones go by bus to the secondary school in the nearest town, ten miles away. The three families get ______(34) well, and enjoy their way of life. There are a few difficulties, of course. Their biggest worry at the moment is money - one of the cars needs replacing, and the roof needs some expensive repairs. But this isn't too serious - the bank has agreed to a loan, which they expect to be able to pay back in three years. And they all say they would much rather go on living in their old farmhouse ______(35) move to a luxury flat in a big city.

Question 33:         

Read the passage and mark A, B, C, or D to indicate the correct answer to each of the blanks.

In a small village in North Yorkshire, there is a big old farmhouse ______(31) three families live together. Alice and George and their three children, Joe and Pam and their two children, and Sue and her baby daughter. The adults divide up the work between them. George does the cooking, Joe and Sue do almost the housework. Pam looks after the shopping and ______(32) the repairs, and Alice takes care of the garden. Alice, George and Sue go out to work. Joe works at home ______(33) computer systems, and Pam, who is a painter, looks after the baby during the day. Two of the children go to school in the village, but the three oldest ones go by bus to the secondary school in the nearest town, ten miles away. The three families get ______(34) well, and enjoy their way of life. There are a few difficulties, of course. Their biggest worry at the moment is money- one of the cars needs replacing, and the roof needs some expensive repairs. But this isn't too serious- the bank has agreed to a loan, which they expect to be able to pay back in three years. And they all say they would much rather go on living in their old farmhouse ______(35) move to a luxury flat in a big city.  

Question 34:

Read the passage and mark A, B, C or D to indicate the correct answer to each of the blanks:

 In a small village in North Yorkshire, there is a big old farmhouse ______(31) three families live together. Alice and George and their three children, Joe and Pam and their two children, and Sue and her baby daughter. The adults divide up the work between them. George does the cooking, Joe and Sue do almost the housework. Pam looks after the shopping and ______(32) the repairs, and Alice takes care of the garden. Alice, George and Sue go out to work. Joe works at home ______(33) computer systems, and Pam, who is a painter, looks after the baby during the day. Two of the children go to school in the village, but the three oldest ones go by bus to the secondary school in the nearest town, ten miles away. The three families get ______(34) well, and enjoy their way of life. There are a few difficulties, of course. Their biggest worry at the moment is money - one of the cars needs replacing, and the roof needs some expensive repairs. But this isn't too serious - the bank has agreed to a loan, which they expect to be able to pay back in three years. And they all say they would much rather go on living in their old farmhouse ______(35) move to a luxury flat in a big city.

Question 35:             

Here are tips that help succeed in your job interview: Always arrive early. If you do not know (46) _________ the organization is located, call for exact directions (47) ____________ advance. Leave some extra time for any traffic, parking, or unexpected events. If you are running late, call right away and let someone know. The best time to arrive is approximately 5 - 10 minutes early. Give yourself the time to read your resume one more time, to catch your breath, and to be ready for the interview. Once you are at the office, treat everyone you encounter with respect. Be (48) _________ to everyone as soon as you walk in the door. Wear a professional business suit. This point should be emphasized enough. First (49) ____________ are extremely important in the interview process. Women should (50)_________ wearing too much jewelry or make up. Men should avoid flashy suits or wearing too much perfume. It is also important that you feel comfortable. While a suit is the standard interview attire in a business environment, if you think it is an informal environment, call before and ask. Regardless, you can never be overdressed if you are wearing a tailored suit.

Question 46:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 19 to 23:

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (19)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (20) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access. Because the federal government provides only limited funds to schools, individual school districts (21)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (22)________ abundant resources, spacious facilities, and curricular and instructional support. In (23) __________, school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged. 

Question 20:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 19 to 23:

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (19)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (20) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access. Because the federal government provides only limited funds to schools, individual school districts (21)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (22)________ abundant resources, spacious facilities, and curricular and instructional support. In (23) __________, school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged. 

Question 22:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 19 to 23:

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (19)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (20) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access. Because the federal government provides only limited funds to schools, individual school districts (21)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (22)________ abundant resources, spacious facilities, and curricular and instructional support. In (23) __________, school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged. 

Question 21:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 19 to 23:

Schools in the United States have not always had a large number of libraries. As recently as 1958 about half of the public schools in the United States had no libraries at all. The (19)_______of public school libraries increased dramatically when the federal government passed the Elementary and Secondary Education Act of 1965, which provided funds for school districts to improve their education programs and facilities, including their libraries. (20) _______, many educators claim that since the legislation was passed federal spending has not increased sufficiently to meet the rising cost of new library technologies such as computer databases and Internet access. Because the federal government provides only limited funds to schools, individual school districts (21)______ on funds from local property taxes to meet the vast majority of public schools tend to reflect the financial capabilities of the communities in which they are located. Districts in wealthy suburbs often have fully staffed libraries (22)________ abundant resources, spacious facilities, and curricular and instructional support. In (23) __________, school districts in many poor areas house their libraries in ordinary classrooms or in small rooms. The libraries in such areas are generally staffed by volunteers, who organize and maintain books that are often out-of-date, irrelevant, or damaged. 

Question 23:

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word or phrase that best fits each of the numbered blanks from 24 to 28:

A long and happy marriage is something that many people wish for, but finding the right partner is (24) _______ more difficult than you might imagine. A friend of mine, Susan had not been very successful in her attempt to find the perfect partner, and she was beginning to lose heart and feel rather depressed. One day she happened to hear someone (25) _______ about a computer dating agency which could help you to find the ideal partner. Susan immediately (26) _______ an appointment to see someone at the agency, then waited to see what would happen. The agency arranged a meeting with a “suitable” partner at the local railway station a week later, although I (27) _______ her not to go. My friend arrived a few minutes early but could see no one who matched the appearance of the man in the photograph she had been sent. She noticed a man waiting under the station clock and (28) _______ a bunch of flowers. But there was no one else around. Suddenly the man started chatting to her and, after a while, asked her if she would like to go and have a coffee. Not until much later did they come to the conclusion that they had both been waiting for each other! When they had both recovered from the shock, they decided that the computer had been right after all!

Question 26: