题目内容

胰高血糖素对糖代谢的作用是( )

A. 促进糖原分解和糖异生
B. 促进糖原分解,抑制糖异生
C. 抑制糖原分解,促进糖异生
D. 抑制糖原分解和糖异生
E. 无作用

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Java语言中,将后缀名为_________的源代码文件编译后形成后缀名为.class的字节码文件。

葡萄糖在肌肉内的代谢如下,但除外( )

A. 糖酵解产生大量乳酸
B. 糖酵解主要在肌肉内进行
C. 糖酵解是氧供应不足情况下的一种供能方式
D. 乳酸可以直接变成6-磷酸葡萄糖以维持血糖恒定
E. 肌肉收缩做功主要靠肌糖原氧化供能

TEXT E As people age, their cells become less efficient and less able replace damaged components. At the same time their tissues stiffen, For example the lungs and the heart muscle expand less successfully, the blood vessels become increasingly rigid, and the ligaments and tendons tighten. Few investigators would attribute such diverse effects to a single cause. Nevertheless, researchers have discovered that a process long known to discolor and toughen foods may also contribute to age-related impairment of both cells and tissues. That process is nonenzymatic glycosylation, whereby glucose becomes attached to proteins without the aid of enzymes. When enzymes attach glucose to proteins (enzymatic glycosylation), they do so at a specific site on a specific protein molecule for a specific purpose. In contrast, the nonenzymatic process adds glucose haphazardly to any of several sites along any available peptide chain within a protein molecule. This nonenzymatic glyeosylation of certain proteins has been understood by food chemists for decades, although few biologists recognized until recently that the same steps could take place in the body. Nonenzymatic glycosylation begins when an aldehyde group (CHO) of glucose and an amino group (HN2) of a protein are attracted to each other. The molecules combine, forming what is called a Schiff base within the protein. This combination is unstable and quickly rearranges itself into a stabler, but still reversible, substance known as an Amadori product. If a given protein persists in the body for months or years, some of its Amadori products slowly dehydrate and rearrange themselves yet again, into new glucose-derived structures. These can combine with various kinds of molecules to farm irreversible structures named advanced glycosylation end products (AGE’s). Most AGE’s are yellowish brown and fluorescent and have specific spectrographic properties. More important for the body, many are also able to cross-link adjacent proteins, particularly ones that give structure to tissues and organs. Although no one has yet satisfactorily described the origin of all such bridges between proteins, many investigators agree that extensive cross-linking of proteins probably contributes to the stiffening and loss of elasticity characteristic of aging tissues. In an attempt to link this process with the development of cataracts (the browning and clouding of the lens of the eye as people age), researchers studied the effect of glucose on solutions of purified crystallin, the major protein in the lens of the eye. Glucose-free solutions remained clear but solutions with glucose caused the proteins to form clusters, suggesting that the molecules had become cross-linked. The clusters diffracted light, making the solution opaque. The researchers also discovered that the pigmented cross-links in human cataracts have the brownish color and fluorescence characteristic of AGE’ s. These data suggest that nonenzymatic glycosylation of lens crystallins may contribute to cataract formation. With which of the following statements concerning the stiffening of aging tissues would the author most likely agree

A. It paradoxically both helps and hinders the longevity of proteins in the human body.
B. It can be counteracted in part by increased ingestion of glucose-free foods.
C. It is exacerbated by increased enzymatic glycosylation.
D. It probably involves the nonenzymatic glycosylation of proteins.

王某是农贸市场个体屠宰户,因生意不好,屡次拖欠税款。某日,税务人员刘某又向王某征收生猪屠宰税,王某不但不给,还破口大骂刘某。刘某继续耐心向其宣讲税收知识,劝说其交税。王某对此感到很不耐烦,推搡刘某,让其离开,刘某则坚持不走,还要求其跟随自己去税务所缴纳税款并接受罚款。王某恼羞成怒,突然拿起挂猪肉用的钢制尖棒扎入刘某大腿正面部分,刘某腿部当即涌出鲜血。刘某随即被旁观群众送往医院救治。 问:(1)如果刘某的伤势经鉴定为重伤,王某构成何罪为什么 (2)如果刘某的伤势经鉴定为轻伤,王某构成何罪为什么

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