问题 问答题 简答题

简述培养基制作的一般要求。

答案

参考答案:

(1)培养基必须含有细菌生长繁殖所需要的营养物质。所用的化学药品必须纯净,称取的份量务必准确。

(2)培养基的酸碱度应符合细菌生长要求。按各种培养基要求准确测定调节pH值。多数细菌生长的适宜pH值为7、2~7、6,呈弱碱性。

(3)培养基的灭菌时间和温度,应按照各种培养基的规定进行,以保证灭菌效果及不损失培养基的必需营养成分。培养基经灭菌后,必须置37℃温箱中培养24小时,无菌生长者方可应用。

(4)所用器皿须洁净,忌用铁或钢质器皿,要求没有抑制细菌生长的物质存在。

(5)制成的培养基应该是透明的,以便观察细菌生长性状以及其他代谢活动所产生的变化。

单项选择题
阅读理解

阅读理解。

     Star hurdler Liu Xiang returned home last night after spending about three months in the United States for

foot operation and recovery.

     Liu and coach Sun Haiping were followed away by officials after arriving at Shanghai Pudong airport at

around 6: 30 pm, and said nothing to the waiting media.

     Liu went straight to the Xinzhuang training base in Shanghai, where he will start on the comeback (恢复)

through rehabilitation (复职) and training.

     Feng Shuyong, vice-director of China's Athletics Administrative Center, said a group of experts is on

standby at the training base to help with Liu's recovery.

     "The experts will give Liu a full check-up tomorrow or the day after and advise regularly on rehabilitation

in the coming months," Feng was quoted by qq. corn as saying.

     The foot injury forced defending champion Liu to quit from the 2008 Beijing Olympics last August after

he limped out of the Bird's Nest in the first round of the men's 110 m hurdles, bitterly disappointing adoring

home fans.

     The 25-year-old Athens Olympic and world champion had successful foot surgery in December at the

Memorial Hermann-Texas Medical Center in Houston, and had four calcium deposits (钙物质) removed from

his right Achilles tendon (跟腱).

     He spent the next three months in Houston for rehabilitation and basic training under the guidance of

doctors there.

     "His recovery is better than we expected. Doctors believe that after three months' rehabilitation and training,

he has actually achieved the level of recovery that generally needs four months," Feng said.

     Liu will, however, be absent from the ongoing annual Chinese People's Political Consultative Conference

(CPPCC) meeting due to the recovery process. Feng said Liu is paying close attention to the meeting through

the Internet, and closely following issues such as athletes' education and life after retirement.

     It is the second time Liu has asked for leave from the annual session after being elected to the CPPCC: He

did not attend last year's meeting because he was at a key competition in Spain.

1. The best title for the passage is _____.

A. Fate and Challenge

B. Liu Xiang Returns after Operation Success

C. No Desire to Be a Representative of CPPCC

D. Happiness and Hardships behind Success

2. Which of the following statements is NOT true according to the passage?

A. The experts will give Liu a full check-up and advise regularly on recovery in the coming months.

B. Liu and his coach were followed away by officials after arriving at Pudong airport at around 6:30 pm.

C. Liu paid close attention to the CPPCC meeting through the Internet, caring graduates' further education.

D. His foot operation was successful and four calcium deposits were removed from his right Achilles tendon.

3. The underlined word "limped" most probably means _____.

A. walked nervously

B. walked quickly

C. walked bitterly

D. walked lamely

4. Liu Xiang was absent from CPPCC in the first time because of _____.

A. recovery process

B. accepting the training

C. lecture abroad

D. a key competition