问题 实验题

为了探究酵母菌的呼吸方式,某同学做了如下课题研究:

(1)假设:在其他条件(如温度、pH)都相同的情况下,影响酵母菌的呼吸方式的因素是氧气。

(2)设计与实验:设计的实验装置如下图中甲、乙所示。可重复实验以确保结果的准确性。

(3)得出结论:如果甲、乙两装置中的石灰水都变混浊,说明酵母菌既能进行__________________,又能进行____________________________。

(4)实验分析:

①.甲装置中的油脂层的作用是___________,甲、乙两装置中产生的气泡量较多的是______装置;产生能量较少的是_________装置,原因是___________________________________。

②.写出酵母菌进行有氧呼吸和无氧呼吸的反应式(以葡萄糖为底物):

有氧呼吸:______________________________;

无氧呼吸:______________________________。

答案

(3)有氧呼吸   无氧呼吸

(4)①.隔绝空气(或氧气)   乙   甲   甲试管中的酵母菌进行无氧呼吸,产物是酒精和二氧化碳,在酒精中还含有大量的化学能没有释放出来

②.C6H12O6+6O2+6H2O→6CO2+12H2O+能量         C6H12O6→2C2H5OH+2CO2+能量(少量)

单项选择题
单项选择题

Another critical factor that plays a part in susceptibility to colds is age. A study done by the University of Michigan School of Public Health revealed particulars that seem to hold true for the general population. Infants are the most cold-ridden group, averaging more than six colds in their first year. Boys have more colds than girls up to age three. After the age of three, girls are more susceptible than boys, and teenage girls average three colds a year to boys’ two.
The general incidence of colds continues to decline into maturity. Elderly people who are in good health have as few as one or two colds annually. One exception is found among people in their twenties, especially women, who show a rise in cold infections, because people in this age group are most likely to have young children. Adults who delay having children until their thirties and forties experience the same sudden increase in cold infections.
The study also found that economics plays an important role. As income increases, the frequency at which colds are reported in the family decreases. Families with the lowest income suffer about a third more colds than families at the upper end. Lower income generally forces people to live in more cramped quarters than those typically occupied by wealthier people, and crowding increases the opportunities for the cold virus to travel from person to person. Low income may also adversely influence diet. The degree to which poor nutrition affects susceptibility to colds is not yet clearly established, but an inadequate diet is suspected of lowering resistance generally.

The phrase "people in this age group" underlined in Paragraph 2 refers to ______ .

A.infants

B.people in their twenties

C.people in their thirties and forties

D.elderly people