SECTION 3
Directions: Each passage in this group is followed by questions based on its content. After reading a passage, choose the best answer to each question. Answer all questions following a passage on the basis of what is stated or implied in the passage.
Many microorganisms survive such environmental stresses as heat, cold
and desiccation not by rapid rates of mitosis, but by producing specialized cells
designed to persist in a dormant state in hostile environments. Most fungi, for
Line example, yield single-celled spores, which, through wind distribution, can
(5) survive for long periods of time before germinating and sprouting fungal
filaments of their own. Other types of bacteria produce a special type of spore
called an endospore, capable of withstanding such extremes as boiling and
freezing temperatures, and even ultraviolet radiation.
Though research results remain tentative, several factors may protect
(10) endospores from environmental stress: they have a low water content, unusual
proteins and a tough spore coat absent in mature bacterial cells. When garden
fruits and vegetables, which may contain botulism endospores, are preserved by
canning at boiling temperatures, we know that these spores survive the heat
and sprout in the food, and as a result, the bacteria generate the botulism toxin
(15) that can lead to food poisoning-proof of their magnificent resilience.
The author's primary purpose in the passage is to
A.describe the limits of biologists' understanding of the phenomenon of cellular dormancy
B.explain how certain organisms have adapted to withstand environmental adversity
C.contrast the survival techniques of two organisms which use dormancy to survive hostile environments
D.explain why endospores are so adept at surviving the traditional canning process
E.suggest which methods are effective for killing endospores at which are not
第1题
中国蓝培养基属于
A.基础培养基
B.营养培养基
C.鉴别培养基
D.选择培养基
E.增菌培养基
第4题
SS琼脂培养基属于()
A.基础培养基
B.增菌培养基
C.选择培养基
D.鉴别培养基
E.厌氧培养基
第6题
庖肉培养基属于何种培养基
A.基础培养基
B.选择培养基
C.鉴别培养基
D.增菌培养基
E.厌氧培养基
第8题
糖发酵管、双糖铁培养基属于何种培养基
A.基础培养基
B.选择培养基
C.鉴别培养基
D.增菌培养基
E.厌氧培养基
第9题
SS培养基属于
A、基础培养基
B、营养培养基
C、选择培养基
D、鉴别培养基
E、增菌培养的培养基
为了保护您的账号安全,请在“上学吧”公众号进行验证,点击“官网服务”-“账号验证”后输入验证码“”完成验证,验证成功后方可继续查看答案!