1．G+菌的细胞壁的特点是____________。
a．较疏松
b．无磷壁酸
c．有脂多糖
d．有脂蛋白
e．肽聚糖含量多
2．细菌细胞壁的主要成分是____________。
a．脂蛋白
b．肽聚糖
c．几丁质
d．胆固醇
e．脂多糖
3．革兰阴性菌细胞壁的特殊组分是____________。
a．肽聚糖
b．磷壁酸
c．外膜
d．脂质双层
e．脂多糖
4．溶菌酶溶菌作用的机制是____________。
a．切断肽聚糖的聚糖支架
b．抑制四肽侧连与五肽交联桥的联结
c．干扰细菌DNA的复制
d．干扰细菌蛋白质的合成
e．损害细胞膜
5．细菌的革兰染色性不同是由于____________。
a．细胞核结构的不同
b．细胞壁结构的不同
c．细胞膜结构的不同
d．磷壁酸的有无
e．中介体的有无
6．青霉素的抗菌机制是____________。
a．切断肽聚糖的聚糖支架
b．抑制四肽侧连与五肽交联桥的联结
c．干扰细菌DNA的复制
d．干扰细菌蛋白质的合成
e．损害细胞膜
7．革兰染色所用染液的顺序是____________。
a．稀释复红，碘液，乙醇，结晶紫
b．结晶紫，乙醇，碘液，稀释复红
c．结晶紫，碘液，乙醇，稀释复红
d．稀释复红，乙醇，结晶紫，碘液
e．稀释复红，结晶紫，碘液，乙醇
8．关于细胞壁的功能，下列哪项是错误的____________。
a．维持菌体固有的形态
b．保护细菌抵抗低渗环境
c．有助于维持菌体内离子的平衡
d．是细菌的运动器官
e．决定细菌菌体的抗原性
9．关于细菌L型的特性，下列错误的是____________。
a．高度多形性
b．革兰染色阴性
c．去除抑制物后，可回复原有形态
d．仍有一定致病力
e．在低渗高琼脂培养基上生长
10．下列不属于细菌特殊结构的是____________。
a．荚膜
b．质粒
c．鞭毛
d．菌毛
e．芽胞
11．下列各种微生物不能通过除菌滤器的是____________。
a．麻疹病毒
b．斑疹伤寒立克次体
c．支原体
d．L型细菌
e．以上都可以通过
12．质粒是细菌的____________。
a．核质DNA
b．胞质中核蛋白体
c．异染颗粒
d．中介体
e．核质外DNA
13．关于细菌细胞壁的功能，叙述错误的是____________。
a．保持一定的形状
b．控制渗透压
c．抵抗青霉素
d．参与物质交换
e．有噬菌体受体
14．细菌细胞膜与真核细胞膜不同之处在于____________。
a．磷脂
b．甘油
c．糖脂
d．固醇类物质
e．脂肪酸
15．与细菌致病力有关的结构是____________。
a．芽胞
b．异染颗粒
c．中介体
d．核蛋白体
e．菌毛
16．Each of teh following statements concerning bacterial spores is correct except____________。
a．Their survival ability is based on their enhanced netabolic activity
b．They are formed by gram-positive rods
c．They can be killed by being heated to 121 for 15 miniutes
d．They contain much less water than bacterial cells
17．Which one of the statements is the nost accurate comparison of human,bacterial,and fungal cell?____________。
a．Human cell undergo mitosis,whereas neither bacteria nor fungi do
b．Human and fungal cells have a similar cell wall,in contrast to bacteria,whose cell wall contains peptidoglycan
c．Human an bacterial cells have plasmids,whereas fungal cells do not
d．Human and fungal cells have similar ribosomes ,whereas bacterial ribosomes are different
18．Each of the following is a typical property of obligate anaerobes expect____________。
a．They generate energy by using the cytochrome systeme
b．They grow best in the absence of air
c．They lack superoxide dismutase
d．They lack catalase
19．The main host defense against bacterial exotoxins is____________。
a．activated macrophages secreting proteases
b．IgG and IgM antibodies
c．helper T cells
d．modulation of host cell receptors in response to toxin
20．Each of the following statements concerning the normal flora is correct except:____________。
a．The most common organism found on the skin is Staphylococcus epidermidis
b．Escherichia coli is a prominent member of the normal flora of the throat
c．The major site where Bacteroides fragilis is found is the colon
d．One of the most common site where staphylococcus aureus is found is the nose
21．of the following choices,the most important function of antibody in host defenses against bacteria is____________。
a．activation of lysozyme that degrades the cell wall
b．acceleration of proteolysis of exotoxins
c．facilitation of phagocytosis
d．inhibition of bacterial protein synthesis
22．Which of the following events is most likely to be due to bacterial conjugation____________。
a．A strain of Corynebacterium diphtheriae produces a toxin encoded by a prophage
b．A stain of pseudomonas aeruginosa produces β-lactamase encoded by a plasmid similar to a plasmid of another gram negative organism
c．An encapsulated strain of Streptococcus pneumoniae acquires the gene for capsule formation from an extract of DNA from another encapsulate strain
d．A gene encoding resistance to gentamicin in the escherichia coli chromosome appears in the genomes of a virulent bacteriophage that has infected E．coli
23．Which one of the following best descibes the mode of action of endotoxin?____________。
a．Degrades lecithin in cell membranes
b．Inactivates elongation factor 2
c．Blocks releases of acetyl choline
d．Causes the release of tumor necrosis factor
24．Each of the following statement concerning bacterial spores is correct except:____________。
a．Spores are formed under adverse environmental conditions such as the absence of a cabon source
b．Spores are resistant to boiling
c．Spore are metabolically inactive and contain dipicolinic acid ,a calcium chelator
d．spores are formed primarily by organisms of the genus Neisseria
25．SITE OF ACTIVITY for Penicillin____________。
a．Integrity of the cell wall
b．Synthesis of the cell wall
c．Synthesis of proteins
d．None of the above
26．MOST IMPORTANT VIRULENCE FACTOR for Clostridium tetani____________。
a．Anti-phagocytic capsule
b．Production of toxins
c．Invasion of tissues
d．Intracellular growth
27．MOST IMPORTANT VIRULENCE FACTOR forVibrio cholerae____________。
a．Anti-phagocytic capsule
b．Production of toxins
c．Invasion of tissues
d．Intracellular growth
28．MOST IMPORTANT VIRULENCE FACTOR forBacterial pharyngitis____________。
a．Cell-mediated response
b．Anti-toxin antibodies
c．Opsonizing antibodies
d．Normal flora
29．MOST IMPORTANT HOST DEFENSE MECHANISM for Malta fever____________。
a．Cell-mediated response
b．Anti-toxin antibodies
c．Opsonizing antibodies
d．Normal flora
30．Each of the following statements concerning the Gram stain is correct except____________。
a．Escherichia coli stains pink because it has a thin peptidoglycan layer
b．streptococcus pyogenes stain blue because it has a thick peptidoglycan layer
c．Mycobacterium tuberculosis stains blue because it has a thick lipid layer
d．Mycoplasma pneumoniae isn't visible in the Gram stain because it doesn't have a cell wall．
31．Each of the following statements concerning the killing of bacteria is correct except____________。
a．Lysozyme in tears can hydrolyze bacterial cell walls
b．Silver nitrate can in activate bacterial enzymes
c．Detergents can disrupt bacterial cellmembranes
d．Ultraviolet light can degrade bacterial capsules
32．Chemical modification of benzylpenicillin(penicillin G)has resulted in several beneficial changes in the clinical use of this drug．Which one of the following is not one of those benificial changes?____________。
a．Lowered frequency of anaphylaxis
b．Increased activity against gramnegative rods
c．increased resistance to stomach acid
d．reduced cleavage by penicillinase
33．"菌落"是指 ____________。
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