Question 1

Which of the following is not a characteristic of endotoxins?

Accepted Answer

A) Stable for hours at 60°C 
B) Induce fever in the host 
C) Poor antigenicity 
D) Located in the cell wall of Gram-negative bacteria 
E) Lethal in small quantities 
A) Stable for hours at 60°C 
B) Induce fever in the host 
C) Poor antigenicity 
D) Located in the cell wall of Gram-negative bacteria 
E) Lethal in small quantities

Question 2

A case of cholera appears in a village that has poor sanitation and is socio-economically depressed.The physician recommends electrolyte infusion,antibiotic treatment of those affected,and widespread sanitation of faucets,handles,and cooking utensils because

Accepted Answer

A) The endotoxin accumulates on these surfaces from contaminated water supplies 
B) Vibrio cholera is transmitted via the fecal-oral route 
C) The toxoids produced by Vibrio cholera are stable for long periods on the hands of people with the infection 
D) If the village is not decontaminated, there will be a very high death rate due to toxic shock 
A) The endotoxin accumulates on these surfaces from contaminated water supplies 
B) Vibrio cholera is transmitted via the fecal-oral route 
C) The toxoids produced by Vibrio cholera are stable for long periods on the hands of people with the infection 
D) If the village is not decontaminated, there will be a very high death rate due to toxic shock

Question 3

The fecal-oral route of contamination refers to the situation where infectious pathogens exit from the host through the _____ and enter another host through the _____.

Accepted Answer

A) anus; skin 
B) Respiratory tract; gastrointestinal tract 
C) Anus; mouth 
D) Genitourinary tract; gastrointestinal tract 
E) Gastrointestinal tract; genitourinary tract 
A) anus; skin 
B) Respiratory tract; gastrointestinal tract 
C) Anus; mouth 
D) Genitourinary tract; gastrointestinal tract 
E) Gastrointestinal tract; genitourinary tract

Question 4

Which of the following common pathogens is mismatched with the disease it causes?

Accepted Answer

A) Bordetella pertussis; whooping cough 
B) Clostridium perfringens; tetanus 
C) Vibrio cholera; cholera 
D) Plasmodium falciparum; malaria 
E) Treponema pallidum; syphilis 
A) Bordetella pertussis; whooping cough 
B) Clostridium perfringens; tetanus 
C) Vibrio cholera; cholera 
D) Plasmodium falciparum; malaria 
E) Treponema pallidum; syphilis

Question 5

A(n)_____ is a thick film of protein secreted by mucous membranes in the mouth that coats teeth and provides a substrate for Staphylococcus mutans to adhere and begin the formation of a slime layer.

Accepted Answer

A) Biofilm 
B) Pellicle 
C) Extracellular matrix 
D) Adhesion 
A) Biofilm 
B) Pellicle 
C) Extracellular matrix 
D) Adhesion

Question 6

To increase phagocytosis of encapsulated bacteria,the host produces

Accepted Answer

A) Antibiotics 
B) Antibodies 
C) Pseudopodia 
D) Defensins 
E) Adhesins 
A) Antibiotics 
B) Antibodies 
C) Pseudopodia 
D) Defensins 
E) Adhesins

Question 7

How does tooth brushing protect teeth from cavity formation?

Accepted Answer

Tooth brushing removes the pellicle,the

Question 8

Connective tissue in the host is compromised by the production of _____ by bacteria.

Accepted Answer

A) Hyaluronidase 
B) Capsules 
C) Streptokinase 
D) M protein 
E) Leukocidins 
A) Hyaluronidase 
B) Capsules 
C) Streptokinase 
D) M protein 
E) Leukocidins

Question 9

Which of the following statements is true?

Accepted Answer

A) Botulinum toxin kill neurons 
B) Exotoxins are often synthesized in an inactive form 
C) Exotoxins make up part of the cell wall of Gram-positive bacteria 
D) Exotoxins are encoded on plasmids can be transmitted to other bacteria 
E) Only one molecule of diphtheria toxin is needed to kill a host cell 
A) Botulinum toxin kill neurons 
B) Exotoxins are often synthesized in an inactive form 
C) Exotoxins make up part of the cell wall of Gram-positive bacteria 
D) Exotoxins are encoded on plasmids can be transmitted to other bacteria 
E) Only one molecule of diphtheria toxin is needed to kill a host cell

Question 10

Both M protein and mycolic acid are

Accepted Answer

A) The same thing with different names 
B) Made by Mycobacterium tuberculosis 
C) Produced by the host as defensive molecules 
D) Part of the cell wall 
E) Inducers of phagocytosis 
A) The same thing with different names 
B) Made by Mycobacterium tuberculosis 
C) Produced by the host as defensive molecules 
D) Part of the cell wall 
E) Inducers of phagocytosis

Question 11

How does Bacillus anthracis ensure that the activity of the anthrax toxin is exerted only inside the host cell?

Accepted Answer

First,the three components of the anthra

Question 12

Which of the following pathogens are virulent only if encapsulated?

Accepted Answer

A) Klebsiella pneumoniae 
B) Bacillus anthracis 
C) Yersinia pestis 
D) Streptococcus pneumoniae 
E) All of the choices 
A) Klebsiella pneumoniae 
B) Bacillus anthracis 
C) Yersinia pestis 
D) Streptococcus pneumoniae 
E) All of the choices

Question 13

Many A-B toxins consist of two subunits,α  and β .Which has specificity for a target cell receptor?

Accepted Answer

A) α 
B) The binding site is dependent on both subunits. 
C) β 
D) Neither α  nor β bind specifically to the target cell; the exotoxin is taken up by pinocytosis. 
A) α 
B) The binding site is dependent on both subunits. 
C) β 
D) Neither α  nor β bind specifically to the target cell; the exotoxin is taken up by pinocytosis.

Question 14

An infection in an abrasion affecting only the epidermis of the skin is unlikely to spread systemically to other sites because

Accepted Answer

A) The micro environment of the epidermis is unfavorable for microbial growth 
B) The dermis beneath secretes antimicrobial substances that contain the infection 
C) There is availability of blood in this layer of the skin 
D) There is no availability of blood in this layer of the skin 
A) The micro environment of the epidermis is unfavorable for microbial growth 
B) The dermis beneath secretes antimicrobial substances that contain the infection 
C) There is availability of blood in this layer of the skin 
D) There is no availability of blood in this layer of the skin

Question 15

What are produced by many pathogens to anchor them to host tissue?

Accepted Answer

A) Adhesions 
B) Pellicles 
C) Leucocidins 
D) Hyaluronidase 
E) Invasins 
A) Adhesions 
B) Pellicles 
C) Leucocidins 
D) Hyaluronidase 
E) Invasins

Question 16

Which of the following is not associated with the parenteral route?

Accepted Answer

A) Contaminated needles used by drug users 
B) Transmission of malaria by mosquitoes 
C) Contaminated food 
D) Tick-derived Lyme disease 
E) Blood products used by hemophiliacs 
A) Contaminated needles used by drug users 
B) Transmission of malaria by mosquitoes 
C) Contaminated food 
D) Tick-derived Lyme disease 
E) Blood products used by hemophiliacs

Question 17

A dose of 1000 bacteria can kill 50% of the animals and a dose of 2400 can kill 70% of the animals.What is the approximate LD50?

Accepted Answer

A) 1000 
B) 2400 
C) 150 
D) 1700 
A) 1000 
B) 2400 
C) 150 
D) 1700

Question 18

What is the general term for components of a pathogen that help it to be infectious?

Accepted Answer

A) Portals of entry 
B) Parenteral characteristic 
C) Transmissible factors 
D) Virulence factors 
E) Adhesion factors 
A) Portals of entry 
B) Parenteral characteristic 
C) Transmissible factors 
D) Virulence factors 
E) Adhesion factors

Question 19

The reason for converting toxins to toxoids for vaccine use is

Accepted Answer

A) To reduce their antigenicity 
B) To increase their toxicity 
C) To stimulate better immune responses 
D) To retain their antigenicity but destroy their toxicity 
A) To reduce their antigenicity 
B) To increase their toxicity 
C) To stimulate better immune responses 
D) To retain their antigenicity but destroy their toxicity

Question 20

The respiratory tract is the main portal of entry for which of the following infectious agents?

Accepted Answer

A)  C. perfringens 
B)  HIV 
C)  Influenza virus 
D)  S. typhi 
E)  V. cholera 
A)  C. perfringens 
B)  HIV 
C)  Influenza virus 
D)  S. typhi 
E)  V. cholera

Exam 5: Requirements for Infection

Which of the following is not a characteristic of endotoxins?

A case of cholera appears in a village that has poor sanitation and is socio-economically depressed.The physician recommends electrolyte infusion,antibiotic treatment of those affected,and widespread sanitation of faucets,handles,and cooking utensils because

The fecal-oral route of contamination refers to the situation where infectious pathogens exit from the host through the _____ and enter another host through the _____.

Which of the following common pathogens is mismatched with the disease it causes?

A(n)_____ is a thick film of protein secreted by mucous membranes in the mouth that coats teeth and provides a substrate for Staphylococcus mutans to adhere and begin the formation of a slime layer.

To increase phagocytosis of encapsulated bacteria,the host produces

How does tooth brushing protect teeth from cavity formation?

Connective tissue in the host is compromised by the production of _____ by bacteria.

Which of the following statements is true?

Both M protein and mycolic acid are

How does Bacillus anthracis ensure that the activity of the anthrax toxin is exerted only inside the host cell?

Which of the following pathogens are virulent only if encapsulated?

Many A-B toxins consist of two subunits,α and β .Which has specificity for a target cell receptor?

An infection in an abrasion affecting only the epidermis of the skin is unlikely to spread systemically to other sites because

What are produced by many pathogens to anchor them to host tissue?

Which of the following is not associated with the parenteral route?

A dose of 1000 bacteria can kill 50% of the animals and a dose of 2400 can kill 70% of the animals.What is the approximate LD50?

What is the general term for components of a pathogen that help it to be infectious?

The reason for converting toxins to toxoids for vaccine use is

The respiratory tract is the main portal of entry for which of the following infectious agents?

What is Microbiology and Why Does it Matter?

Fundamental Chemistry for Microbiology

Essentials of Metabolism

An Introduction to Cell Structure and Host-Pathogen Relationships

Transmission of Infection, the Compromised Host, Epidemiology, and Diagnosing Infections

Principles of Disease

Emerging and Re-Emerging Infectious Disease

The Clinical Significance of Bacterial Anatomy

Bacterial Growth

Microbial Genetics and Infectious Disease

The Structure and Infection Cycle of Viruses

Viral Infection

Parasitic and Fungal Infections

The Innate Immune Response

The Adaptive Immune Response

Failures of the Immune Response

Control of Microbial Growth with Disinfectants and Antiseptics

Antibiotics and Antimicrobial Drugs

Antibiotic Resistance

Infections of the Respiratory System

Infections of the Digestive System

Infections of the Genitourinary System

Infections of the Central Nervous System

Infections of the Blood and Lymph

Infections of the Skin and Eyes

Filters

The fecal-oral route of contamination refers to the situation where infectious pathogens exit from the host through the _ and enter another host through the _.

A dose of 1000 bacteria can kill 50% of the animals and a dose of 2400 can kill 70% of the animals.What is the approximate LD₅₀?