超星 - 细菌感染与致病机制--章节练习

单选题

Which statement is true about an exotoxin?

A. It is commonly produced by gram negative bacteria
B. Its 50% lethal dose may be as low as the picogram level
C. It is composed primarily of carbohydrate
D. It is LPS associated
E. It is heat stable

查看答案

单选题

Biological products commonly used for passive immunity are

A. killed bacterial cells
B. the vaccine
C. BCG
D. toxoid
E. antitoxin

查看答案

单选题

The pathogenicity of bacteria mainly depends on bacterial

A. basic and special structures
B. catabolites
C. invasiveness and toxins
D. ways to invade the body
E. number of invading bacteria

查看答案

单选题

Which of the following statements about lipopolysaccharide is correct?

A. It interacts with macrophages and monocytes yielding release of cytokines
B. The toxic component is the O side chain
C. It forms holes in red blood cell membranes yielding hemolysis
D. It causes hypothermia
E. It causes paralysis

查看答案

单选题

Which of the following best describes the mechanism of actionof diphtheria toxin?

A. Forms pores in red blood cells causing hemolysis
B. Degrades lecithin in eukaryotic cell membranes
Causes release of tumor necrosis factor
D. Inhibits elongation factor 2
E. Causes increased adenylate cyclase activity

查看答案

单选题

Which of the following statements correctly describes enterotoxins?

A. They are not produced bySalmonella species
B. They are not produced byEscherichia coli
C. They stimulate adenyl cyclase
D. They are not antigenic
E. They contain lipid A

查看答案

单选题

All of the following statements concerning endotoxins of gram-negative bacteria are true EXCEPT that ( )

A. they differ markedly in their toxicity according to their specific bacterial origins
B. they are found in the blood of patients suffering from endotoxic shock
C. they consist mainly of lipopolysaccharide complexes
D. they induce the release of endogenous pyrogens from leukocytes
E. they are found only in gram-negative bacteria

查看答案

单选题

Which of the following statements is true?

A. Endotoxins produce varied effects such as neurotoxic or protein inhibition effects, but exotoxins produced generalized irritation and inflammation of epithelial surfaces
B. Endotoxins are found attached to the cell wall of certain bacteria, but exotoxins are secreted toxins that may exhibit their effect independently of the presence of the bacteria
C. Endotoxins include the neurotoxins of botulism and tetanus, while exotoxins include the enterotoxin of Staphylococcus aureus
D. More than one of the above statements is true
E. None of the above is true

查看答案

单选题

The ability of a microbial species to cause disease is its ( )

A. pathogenicity
B. cuteness
C. mutation
D. infectious index
E. communicability

查看答案

单选题

Which of the following is an endotoxin?

A. Cholera toxin
B. Diphtheria toxin
C. Plague toxin
D. LPS of salmonella
Enterotoxin

查看答案