问题 填空题

利用微生物分解玉米淀粉生产糖浆,具有广阔的应用前景。但现在野生菌株对淀粉的转化效率低,某同学尝试对其进行改造,以获得高效菌株。

若已得到两株变异菌株Ⅰ和Ⅱ,其淀粉转化率较高。经测定菌株Ⅰ淀粉酶的催化活性高,菌株Ⅱ的淀粉酶蛋白含量高。进一步研究发现,突变发生在淀粉酶基因的编码区或非编码区,可推测出菌株工的突变发生在()区,菌株Ⅱ的突变发生在()区。

答案

参考答案:编码 非编码

解析:

(1)筛选菌株,首先应是配制固体培养基,其碳源是玉米淀粉;其次要将野生菌株接种到培养基上。用紫外线照射的目的是对野生菌株进行诱变处理;加碘液是为了检验淀粉有没有被分解,如果颜色变浅,说明淀粉被分解了,这种菌落即为初选菌落。(2)依题意,菌株Ⅰ淀粉酶的催化活性高,说明淀粉酶种类有变化,该突变发生在编码区,菌株Ⅱ淀粉酶的蛋白含量高无种类变化,说明该突变发生在非编码区。

单项选择题 A1型题
单项选择题

Beyond question, Clinton was supposed to close up, stay out of sight, and avoid second- guessing his wife’s boss. After his ego blustered into oncoming traffic during Hillary’s heated primary race (1) Obama, the nation suffered from yet another turn of Clinton fatigue.

(2) this week Bill Clinton showed an instinct for robust, inclusive leadership that the (3) White House occupant could make good use of right for the time being. With President Obama struggling to (4) the political damage from the Gulf oil spill, Clinton not only can’t help himself—he’s worth being listened.

The conventional-wisdom (5) on President Obama’s early reaction to the spill was (6) he didn’t emote enough. He didn’t feel the (7) of all those people in the crisis whose livelihood would be destroyed, whose clean waters and wildlife would be (8) in black gunk.

Clinton considers this is an unfair (9) but offers a different—and more pointed— lesson to his young successor. "I think we ought to (10) in the same boat for a while... Let’s just (11) the problem, and then we can hold everybody responsible and emote or not emote, " Clinton conversed (12) CNN Anchor Wolf Blitzer.

Obama’s first (13) after the oil spill was to "feel the blame" rather than "feel the pain, " which are pretty sarcastic words as it were. No one intends to let British Petroleum (BP) management (14) the hook—for dangerously cutting corners, and for a (15) safety record. However, the President’s (16) focus on scolding BP consumed (17) White House energy while the oil gushed.

Great leaders don’t rush to criticise; Instead they instinctively (18) solutions. Rudy Giuliani, who didn’t stop to blame (19) intelligence for letting it happen, stood out from New York mayor with a girlfriend problem to 9/11 hero when he took control of a crisis and instilled confidence that a ravaged city could (20) beyond a terrorist attack.

11()

A.fix

B.discuss

C.consider

D.raise