问题 解答题

有人将线粒体比喻为“动力车间”,因为线粒体能够使细胞内的______,经过复杂的化学反应过程,转变成______和______,同时将其中的______释放出来,供给细胞生活利用.

答案

线粒体能将细胞中的一些有机物当燃料,使这些与氧结合,经过复杂的过程,转变为二氧化碳和水,同时将有机物中的化学能释放出来,供细胞利用.此过程称作呼吸作用.呼吸作用的表达式可以这样表示:有机物+氧→二氧化碳+水+能量.

故答案为:有机物;二氧化碳;水;化学能(能量)

解答题
单项选择题


Directions: There are 10 blanks in the following passage. For each numbered blank, there are 4 choices marked A, B, C and D.

It is difficult to imagine what life would be like without memory. The meanings of thousands of everyday perceptions, the bases (51) the decisions we make, and the roots of our habits and skills are to be (52) in our past experiences, which are brought into the present (53) memory.
Memory can be defined as the capacity to keep (54) available for later use. It includes not only "remembering" things like arithmetic or historical facts, but also any change in the way an animal typically behaves. Memory is (55) when a rat gives up eating grain because he has sniffed something suspicious in the grain pile. Memory is also involved when a six-year-old child learns to swing a baseball bat.
Memory (56) not only in humans and animals but also in some physical objects and machines. Computers, for example, contain devices for storing data for later use. It is interesting to compare the memory-storage capacity of a computer (57) that of a human being. The in stant-access memory of a large computer may hold up to 100 000 "words" —ready for (58) use. An average American teenager probably recognizes the meanings of about 100 000 words of English. However, this is but a fraction of the total (59) of information which the teenager has stored. Consider, for example, the number of facts and places that the teenager can recognize on sight. The use of words is the basis of the advanced problem-solving intelligence of human beings. A large part of a person’s memory is in terms of words and (60) of words.

A.combinations

B.connections

C.co-ordinations

D.collections