Thymine kinase xúc tác phản ứng phosphoryl hóa với cơ chất là thymine và acyclovir như phản ứng dưới đây. Các enzyme kinase của tế bào có thể chuyển hóa acyclo-GMP thành acyclo-GTP. Acyl-GTP là một cơ chất của DNA polymerase. Virus Herpes là một Adeno virus gây bệnh zona thần kinh, có gene mã hóa thymine kinase và DNA polymerase của nó. Ái lực của acyclovir với thymine kinase cao gấp 200 lần so với thymine kinase của tế bào người.

• Giải thích cơ chế điều trị zona thần kinh bằng thuốc acyclovir.

• Một đột biến làm ở virus giảm ái lực của DNA polymerase virus với acyclo-GTP thì tác dụng điều trị bằng acyclovir tăng lên hay giảm xuống ? Tại sao ?

Đọc đoạn văn sau và trả lời các câu hỏi:

A balanced diet contains proteins, which are composed of complex amino acids. There are 20 types of amino acids, comprising about 16 percent of the body weight in a lean individual. A body needs all 20 to be healthy. Amino acids can be divided into two groups: essential 5 and nonessential. There are 9 essential amino acids. These are the proteins that the body cannot produce by itself, so a healthy individual must ingest them. The 11 nonessential amino acids, on the other hand, are produced by the body, so it is not necessary to ingest them. Proteins are described as being either high-quality or low-quality, 10 depending on how many of the 9 essential amino acids the food contains. High-quality proteins, typically found in animal meats, are proteins that have ample amounts of the essential amino acids. Low-quality proteins are mainly plant proteins and usually lack one or more of the essential amino acids. Since people who follow a strict vegetarian 15 diet are ingesting only low-quality proteins, they must make sure that their diets contain a variety of proteins, in order to ensure that what is lacking in one food is available in another. This process of selecting a variety of the essential proteins is called protein complementation. Since an insufficient amount of protein in the 20 diet can be crippling, and prolonged absence of proteins can cause death, it is imperative that a vegetarian diet contains an ample amount of the essential proteins.

1. With what topic is this passage primarily concerned?
(A) the 20 types of amino acids
(B) high- and low-quality proteins
(C) the process of complementation
(D) healthy diets for vegetarians
2. The word "lean" in line 3 could be best replaced by
(A) thin
(B) fat
(C) tall
(D) short
3. The word "ingest" in line 7 is closest in meaning to which of the following?
(A) chew
(B) swallow
(C) suck
(D) drink
4. The word "ample" in line 13 is closest in meaning to which of the following?
(A) meager
(B) frequent
(C) substantial
(D) harmful
5. Which of the following would NOT be an example of a low-quality protein?
(A) legumes
(B) apples
(C) grains
(D) tuna
6. As used in line 14, which of the following words is closest in meaning to "strict"?
(A) responsible
(B) casual
(C) harmonious
(D) rigid
7. According to the passage, a vegetarian could die from insufficient protein ingestion if he or she
(A) did not follow a varied and properly protein-complemented diet.
(B) ate too many animal proteins,and could not digest them properly.
(C) did not follow a diet in which nonessential proteins were ingested.
(D) ate too many low-quality proteins.
8. Which of the following is closest in meaning to the word "crippling" as used in line 20?
(A) discouraging
(B) betraying
(C) incapacitating
(D) amazing
9. Which of the following words could best replace the word "prolonged" in line 20?
(A) narrow
(B) hollow
(C) hard-hearted
(D) extended
10. In line 21, the word "imperative" can be best replaced by
(A) crucial
(B) impossible
(C) wonderful
(D) satisfying
11. Which of the following best describes the author's tone in this passage?
(A) forceful
(B) light
(C) casual
(D) argumentative
12. Which statement best describes the organization of this passage?
(A) Contrasting views concerning proteins are compared.
(B) The author moves from a general comment to a specific argument.
(C) A statement is given and its cause is then discussed.
(D) Items are discussed in their order of importance.

Dịch:ko dùng google dịch vì hay bị sai

-A mixture contains different subtances that are not chemically joined to each other.

-Pure subtances are composed of only one kind of molecule in it.Most of the things in this world are mixtures.

-A mixture can be separated physically or chemically.

-When a salt and water mixture is separated by heating,pure water can be obtained.

Answer the questions:(bằng tiếng anh)

1.how can you separate a mixture of water and sand?

..................................................................................................................................................................................................................................................................................................................................................................................................................

2.What can you do to separate iron filings and salt

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Hepl.Ngay mai tui thi roi!Thanks

dịch đoạn văn sau sang tiếng việt:

Tricksy by nature, pixies particularly delight in tormenting humans. For this reason, they cam be found living in suburban and rural areas, and sometimes even in the parks of cities,any greenward,basically,where people frequent

Ranging between two feet and the height of a human child, pixies ( also known as pixies) make their homes in the hollows of logs ,lean-tos formed by felled trees,and in gardens.Unlike boggarts and brownies,pixies never live inside houses,prefering to dwell outdoors.They sometimes can be spotted alone but are more commonly found in groups of three to five.Their desire to dwell in groups place them in the trooping category within the Invisible world

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

According to sociologists, there are several different ways in which a person may be recognized as the leader of a social group in the United States. In the family, traditional cultural patterns confer leadership on one or both of the parents. In other cases, such as friendship groups, one or more persons may gradually (26)__________as leaders, although there is no formal process of selection. In larger groups, leaders are usually chosen formally through election or recruitment.

(27)__________of the common belief that leaders are people with unusual personal ability, decades of research have failed to produce consistent evidence that there is any category of “natural leaders”. It seems that there is no set of personal qualities that all leaders have (28)__________common;rather, virtually any person may be recognized as a leader if the person has qualities that meet the needs of that particular group.

Furthermore, although it is commonly supposed that social groups have a single leader, research suggests that there are (29)__________two different leadership roles that are held by different individuals. Instrumental leadership emphasizes the completion of tasks by a social group. Group members look to instrumental leaders to “get things done”. Expressive leadership, on the other hand, is leadership (30)__________ emphasizes the collective well-being of a social group’s members.

Question 30

A. which  

B. who  

C. what

D. those

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

According to sociologists, there are several different ways in which a person may be recognized as the leader of a social group in the United States. In the family, traditional cultural patterns confer leadership on one or both of the parents. In other cases, such as friendship groups, one or more persons may gradually (26)__________as leaders, although there is no formal process of selection. In larger groups, leaders are usually chosen formally through election or recruitment.

(27)__________of the common belief that leaders are people with unusual personal ability, decades of research have failed to produce consistent evidence that there is any category of “natural leaders”. It seems that there is no set of personal qualities that all leaders have (28)__________common;rather, virtually any person may be recognized as a leader if the person has qualities that meet the needs of that particular group.

Furthermore, although it is commonly supposed that social groups have a single leader, research suggests that there are (29)__________two different leadership roles that are held by different individuals. Instrumental leadership emphasizes the completion of tasks by a social group. Group members look to instrumental leaders to “get things done”. Expressive leadership, on the other hand, is leadership (30)__________ emphasizes the collective well-being of a social group’s members.

Question 28

A. on

B. in 

C. by

D. at

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

According to sociologists, there are several different ways in which a person may be recognized as the leader of a social group in the United States. In the family, traditional cultural patterns confer leadership on one or both of the parents. In other cases, such as friendship groups, one or more persons may gradually (26) ______ as leaders, although there is no formal process of selection. In larger groups, leaders are usually chosen formally through election or recruitment.

(27) ______ of the common belief that leaders are people with unusual personal ability, decades of research have failed to produce consistent evidence that there is any category of “natural leaders”. It seems that there is no set of personal qualities that all leaders have (28) ______ common; rather, virtually any person may be recognized as a leader if the person has qualities that meet the needs of that particular group.

Furthermore, although it is commonly supposed that social groups have a single leader, research suggests that there are (29) ______ two different leadership roles that are held by different individuals. Instrumental leadership emphasizes the completion of tasks by a social group. Group members look to instrumental leaders to “get things done”. Expressive leadership, on the other hand, is leadership (30) ______ emphasizes the collective well-being of a social group’s members.

Điền vào ô số 30

A. which 

B. who 

C. what 

D. those