Microbio Final Exam pt. 2 Flashcards

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1. Normal microbiota

A) leaves the body after a while

B) are normally found in blood

C) both indefinitely colonize the body and take up residence in sites such as the colon and mouth

D) almost always cause disease in the host

Answer: C


2. Development of emerging infectious disease can be a result of all of the following EXCEPT

A) modern transportation

B) overuse of antibiotics

C) changes in the environment

D) use of genetically modified foods

Answer: D


3. All of the below are examples of a biofilm EXCEPT

A) archaea as part of the plankton community in the open ocean

B) vegetations on a patient heart valve

C) dental plaque

D) slimy layer on riverbed rocks

Answer: A


4. The DNA found in most bacterial cells

A) is found in multiple copies

B) is surrounded by a nuclear membrane

C) is circular in structure

D) is linear in structure

Answer: C


5. A system of classification grouping organisms into 3 domains based on the cellular organization of organisms was devised by

A) Robert Koch

B) Carolus Linnaeus

C) Carl Woese

D) Louis Pasteur

Answer: C


6. Which microscope achieves the highest magnification and greatest resolution?

A) fluorescence microscope

B) darkfield microscope

C) compound light microscope

D) electron microscope

Answer: D


7. Which microscope is used to observe a specimen that emits light when illuminated with ultraviolet light?

A) fluorescence microscope

B) electron microscope

C) darkfield microscope

D) light microscope

Answer: A


8. You are performing a Gram stain on gram-positive bacteria and you stop after the addition of the first dye. What is the appearance of the bacteria at this point?

A) purple

B) brown

C) colorless

D) red

Answer: A


9. Which of the following statements is INCORRECT?

A) They lack membrane-enclosed organelles.

B) They reproduce by binary fission.

C) They typically have a circular chromosome.

D) They lack a plasma membrane.

Answer: D


10. By which of the following mechanisms can a cell transport a substance from a lower to a higher concentration?

A) extracellular enzymes

B) simple diffusion

C) active transport

D) aquaporins

Answer: C


11. Which of the following statements is TRUE?

A) Endospores allow a cell to survive environmental changes by producing a dormant period with no growth

B) Endospores are for reproduction

C) Endospores are easily stained in a Gram stain.

D) A cell produces one endospore and keeps growing

Answer: A


12. The difference between simple diffusion and facilitated diffusion is that facilitated diffusion

A) moves materials from a lower to a higher concentration

B) requires transporter proteins

C) moves materials from a higher to a lower concentration

D) does not require ATP

Answer: B


13. A culture medium consisting of agar, yeast extract, and beef heart is a

A) complex medium

B) chemically defined medium

C) reducing medium

D) selective medium

Answer: A


14. The term aerotolerant anaerobe refers to an organism that

A) tolerates normal atmospheric nitrogen gas levels

B) is killed by oxygen

C) does not oxygen but tolerates it

D) requires more oxygen that is present in air

Answer: C


15. Where are phospholipids most likely found in a prokaryotic cell?

A) ribosomes

B) flagella

C) the plasma membrane

D) the plasma membrane and organelles

Answer: C


16. Oxygen crosses a plasma membrane

A) through simple diffusion

B) by osmosis

C) with the help of a nonspecific transporter

D) through porins

Answer: A


17. Patients with indwelling catheters (long-term tubes inserted into body orifices for drainage, such as through the urethra and into the urinary bladder) are susceptible to infections because

A) biofilms develop on catheters

B) their immune systems are weakened

C) infections can be transmitted from other people

D) injected solutions are contaminated

Answer: A


18. Which of the following is a limitation of the autoclave?

A) it cannot kill endospores

B) it requires an excessively long time to achieve sterilization

C) it cannot be used with glassware

D) it cannot be used with heat-labile materials

Answer: D


19. Which concentration of ethanol is the most effective bactericide? (think hand sanitizer!!!)

A) 70 percent

B) 50 percent

C) 40 percent

D) 100 percent

Answer: A


20. The addition of which of the following to a culture medium will neutralize acids?

A) buffers

B) heat

C) sugars

D) pH

Answer: A


21. How do all viruses differ from bacteria?

A) Viruses are not composed of cells.

B) Viruses do not have any nucleic acid.

C) Viruses are filterable.

D) Viruses do not replicate.

Answer: A


22. Shingles is an example of

A) reactivation of latent virus

B) lytic virus

C) lysogeny

D) transformation

Answer: A


23. An infectious protein is a

A) retrovirus

B) bacteriophage

C) papovavirus

D) prion

Answer: D


24. Most drugs that interfere with viral multiplication also interfere with host cell functions

A) True

B) False

Answer: A


25. Dogs do not get measles because their cells lack the correct receptor sites for that virus.

A) True

B) False

Answer: A


26. Many enzymes in both prokaryotic and eukaryotic cells are compartmentalized within organelles.

A) True

B) False

Answer: B


27. Eukaryotes lack organelles.

A) True

B) False

Answer: B


28. New cell numbers balanced by death of cells.

stationary phase


29. No cell division but intense metabolic activity.

lag phase


30. A logarithmic plot of the population produces an ascending straight line.

log phase


31. In a completed Gram stain, gram-positive bacteria are purple.

A) True

B) False

Answer: A


32. Spontaneous generation refers to living cells arising only from other living cells

A) True

B) False

Answer: B


33. An isolated colony on a streak plate contains millions (or even billions) of identical cells all arising from one initial cell

A) True

B) False

Answer: A


34. All pathogens known to infect humans have been identified at this point in time.

A) True

B) False

Answer: B


35. Most pathogenic bacteria are mesophiles

A) True

B) False

Answer: A


36. A South San Francisco child enjoyed bath time at his home because of the colorful orange and red water. The water did not have this rusty color at its source, and the water department could not culture the Thiobacillus bacteria responsible for the rusty color from the source. How were the bacteria getting into the household water? What bacterial structures make this possible?

The bacteria was able to get into the household water because of the location and condition of where the child lives. Because of binary fission, the bacteria was able to multiply and infect the household's water. Bacteria may also contain flagella which allows the bacteria to travel. There is also biofilm on the pipes.


37. A patient with a heart pacemaker received antibiotic therapy for streptococcal bacteremia (bacteria in the blood). One month later, he was treated for recurrence of the bacteremia. When he returned 6 weeks later, again with bacteremia, the physician recommended replacing the pacemaker. Why would this cure his condition? What was on his pacemaker allowing bacteria to grow and be resistant to antibiotic therapy?

Replacing the pacemaker would cure his condition because the pacemaker he has now contains a biofilm causing bacteremia. By replacing it with a new one, without a biofilm on it, he should not have any bacteremia. Biofilm is resistant to antibiotic.


38. Discuss, briefly, why viruses are considered infectious "particles" on the borderline between living and non-living.

Viruses are considered infectious "particles" because they're obligatory parasites. Depending on the host and the host's cellular factors, the virus can cling inside the host and feed off from it making it infectious to other people.


39. What conditions that are characteristic of the food tend to retard spoilage in each of the following foods?

Grape Jelly

Salted fish

Grape jelly - is acidic and also has a relatively high osmotic pressure from added sugars

Salted fish - have high osmotic pressures.


40. You are growing bacteria in the lab, at which phase of growth (think growth curve) would you add antibiotics in their media to cause the most adverse effects on the bacterial population.

I would add antibiotics to the log phase. The log phase is when there is an increase of curve.


41. Used to grow obligate anaerobes

reducing media


42. Nutrients digests or extract; exact chemical composition varies slightly from batch to batch

complex media


43. Designed to suppress the growth of unwanted bacteria and to encourage growth of desired microbes

selective media


44. This term _____ refers to the spectrum of host cells a virus can infect.

host range


45. Which of the following statements is FALSE?

A) This leading strand of DNA is made continuously

B) DNA polymerase joins nucleotides in one direction (5' to 3') only

C) DNA replication proceeds in only one direction around the bacterial chromosome

D) Multiple replication forks are possible on a bacterial chromosome

Answer: C


46. DNA is constructed of

A) two strands of nucleotides running in an antiparallel configuration

B) None of the answers is correct

C) a single strand of nucleotides with internal hydrogen bonding

D) two complementary strands of nucleotides bonded A-C and G-T

Answer: A


47. An enzyme produced in response to the presence of a substrate is called a(n)

A) repressible enzyme

B) operator

C) restriction enzyme

D) inducible enzyme

Answer: D


48. Transformation is the transfer of DNA from a donor to a recipient cell

A) by cell-to-cell contact

B) by crossing over

C) as naked DNA in solution

D) by a bacteriophage

Answer: C


49. Synthesis of a repressible enzyme is stopped by the

A) corepressor binding to the operator

B) end product binding to the promoter

C) corepressor-repressor complex binding to the operator

D) substrate binding to the repressor

Answer: C


50. An enzyme that makes covalent bond between Okazaki fragments in the lagging strand of DNA being replicated is


B) DNA helicase

C) RNA polymerase

D) DNA ligase

Answer: D


51. Generalized transduction occurs when a bacteriophage inadvertently packages the wrong material into one of its newly-formed protein coats. While the source of this material may vary, its always:



C) protein


Answer: B


52. Recombination will always alter a cell's genotype.

A) True

B) False

Answer: A


53. Bacteria usually contain multiple chromosomes.

A) True

B) False

Answer: B


54. In the Ames test, any colonies that form on the control plates, in the absence of chemical being tested, should be the result of spontaneous mutations.

A) True


Answer: A


55. Explain why the following statement is false: Sexual reproduction is the only mechanism for genetic change.

Genetic change, or mutation can be classified into germ line mutation and somatic mutation.


56. The restriction enzyme EcoRI recognizes the sequence GAATTC. Which of the following is TRUE of DNA after it is treated with EcoRI?

A) All of the DNA fragments will have single-stranded regions ending in AT.

B) All of the DNA will be circular.

C) All of the DNA fragments will have single-stranded regions ending in AA.

D) All of the DNA will have blunt ends.

Answer: C


57. Self-replicating DNA used to transmit a gene from one organism to another is a

A) southern blot


C) clone

D) vector

Answer: D


58. You want to determine whether a person has a certain mutant gene. The process involves using a primer and a heat-stable DNA polymerase. This process is

A) restriction mapping


C) site-directed mutagenesis

D) translation

Answer: B


59. A restriction fragment is

A) a segment of mRNA

B) a segment of DNA

C) a gene

D) a segment of tRNA

Answer: B


60. PCR can be used to identify an unknown bacterium because

A) the DNA primer is specific to particular target DNA sequences

B) all cells have DNA

C) DNA polymerase will replicate any bacterial DNA

D) DNA can be electrophoresed

Answer: A


61. The term biotechnology refers exclusively to the use of genetically engineered organisms for the production of desired products.

A) True

B) False

Answer: B


62. In recombinant DNA technology, a vector is a self-replicating segment of DNA, such as a plasmid or viral genome

A) True

B) False

Answer: A


63. Explain briefly how and why are restriction enzymes used to make recombinant DNA?

Restriction enzymes cut DNA into fragments of a size suitable for cloning. Second, many restriction enzymes make staggered cuts that create single-stranded sticky ends conducive to the formation of recombinant DNA.


64. Antibiotic resistance is a result of my body fighting the effects of a specific antibiotic.

A) True

B) False

Answer: B


65. If you use antibacterial soaps for everyday cleaning, you could unwittingly be creating super germs that are resistant to antibiotics.

A) True

B) False

Answer: A


66. What is antibiotic resistance? What are the major causes of it?

Antibiotic resistance happens when germs like bacteria and fungi develop the ability to defeat the drugs designed to kill them. Major causes include overuse of antibiotics and poor infection control.


67. What is the best defense against MRSA?

A) the MRSA vaccine

B) antiviral drugs

C) antibiotics

D) good hygiene

Answer: D


68. Which of the following statements about drug resistance is FALSE?

A) It may be carried on a plasmid.

B) It is found only in gram-negative bacteria.

C) It may be due to decreased uptake of a drug.

D) It may be transferred from one bacterium to another during conjugation.

Answer: B


69. Chloramphenicol binds to the 50S ribosome subunit. What effect would occur if this drug is administered to a eukaryote?

A) The drug would bind to the 50S ribosome subunit, but at a different location, and protein synthesis would continue.

B) Nothing- eukaryotes have a 60S large ribosomal subunit, not a 50S

C) The drug would bind instead to the 30S ribosome subunit, but still shut down protein synthesis

D) The drug would effectively shut down protein synthesis in the eukaryote

Answer: B


70. Use of antibiotics in animal feed leads to antibiotic-resistant bacteria because

A) the antibiotics cause new mutations to occur in the surviving bacteria, which results in resistance to antibiotics

B) the antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.

C) The antibiotics persist in soil and water.

D) Bacteria from other animals replace those killed by antibiotics.

Answer: B


71. Explain selective toxicity when referring to an antimicrobial drug.

Refers to the ability of an antimicrobial drug to harm the target microbe without harming the host


72. Differentiate between intrinsic and acquired resistance.

Intrinsic - bacteria natural resistant to an antibiotic due to physical characteristics

Acquired - developed through mutation or transfer of genetic material


73. A drug that inhibits mitosis, such as griseofulvin, would be more effective against

A) gram-negative bacteria

B) gram-positive bacteria

C) mycobacteria

D) fungi

Answer: D


74. Most of the available antimicrobial agents are effective against

A) viruses

B) fungi

C) protozoa

D) bacteria

Answer: D

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75. In Table 20.2, the most effective antibiotic tested was

A) D

B) C

C) A

D) B

Answer: A

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76. In Table 20.2, which antibiotic would be most useful for treating a Salmonella infection?

A) D

B) The answer cannot be determined based on the information provided.

C) B

D) A

Answer: B


77. Community acquired MRSA is typically less virulent than healthcare-associated MRSA.

A) True

B) False

Answer: B

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78. How many pieces will EcoRI produce from the plasmid shown in Figure 9.1?

A) 5

B) 2

C) 3

D) 1

Answer: B

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79. In Figure 9.4, the bacteria transformed with the recombinant plasmid and plated on media containing ampicillin and X-gal will

A) form blue, ampicillin-sensitive colonies

B) form white, ampicillin-resistant colonies

C) not grow

D) form white, ampicillin-sensitive colonies

Answer: B


80. This microbe is acquired by humans as infants and is essential for good health. Acquiring closely related strain causes severe stomach cramps, bloody diarrhea, and vomiting. What is the microbe?

E. coli


81. Explain, briefly, the difficulties in developing antiviral drugs against DNA viruses, when compared to RNA viruses.

They have different enzymes for replication(RNA), DNA viruses use host machinery or similar processes for replication. Not all RNA viruses use reverse transcriptase


82. The most frequently used portal of entry for pathogens is the

A) parent to fetus

B) skin

C) mucous membranes of the respiratory tract

D) mucous membranes of the gastrointestinal tract

Answer: C


83. SARS-CoV-2 is described as a zoonotic virus - what does this mean?

A) such viruses are confined to animals

B) They do not cause disease in humans

C) They emerge from animals to cross the species barrier infrequently.

D) They cause pandemics

Answer: C


84. Endotoxins are

A) part of the gram-negative cell wall

B) A-B toxins

C) associated with gram-positive bacteria

D) molecules that bind nerve cells

Answer: A


85. Which of the following contributes to the virulence of a pathogen?

A) numbers of microorganisms that gain access to a host and evasion of host defenses

B) numbers of microorganisms that gain access to a host, evasion of host defenses, and toxin production

C) evasion of host defenses

D) toxin production

Answer: B


86. Innate immunity

A) is nonspecific and present at birth

B) involves T cells and B cells

C) is slower than adaptive immunity in responding to pathogens

D) involves a memory component

Answer: A


87. What type of immunity results from vaccination?

A) artificially acquired active immunity

B) artificially acquired passive

C) innate immunity

D) naturally acquired passive immunity

Answer: A


88. Where are B cells and T cells "born"?

A) in the thymus

B) in the thyroid

C) in the bone marrow

D) in the blood

Answer: C


89. Which one of the following is an example of an indirect method of disease transmission?

A) coughing

B) sneezing

C) shaking hands

D) eating contaminated food

Answer: D


90. What does better describe the coronavirus structure?

A) club-shaped glycoprotein spikes protrude through a lipid bilayer

B) large regimented barrel shaped virus

C) An icosahedral large pleomorphic virus

D) An icosahedral structure with an envelope

Answer: A


91. Phage therapy has been used in the past as an effective, common antiviral treatment.

A) True

B) False

Answer: B


92. COVID-19 spreads between people in close contact, closer than around _____ feet.

A) 4

B) 6

C) 3

D) 2

Answer: B


93. If you use antibacterial soaps for everyday cleaning, you could unwittingly be creating super-germs that are resistant to antibiotics.

A) True

B) False

Answer: A


94. We have been reading about acquired immunity (or herd immunity) for COVID-19, this is resistance that is developed by the host as a result of previous exposure to a natural or artificial pathogen or foreign substance.

A) True

B) False

Answer: A


95. To help avoid contracting and spreading SARS-CoV-2, you should wash your hands frequently with soap and water for a least ______ seconds.

A) 15

B) 3

C) 30

D) 20

Answer: D


96. List at least 2 types of reservoirs of infection.

humans and animals


97. Identify the sequence of stages exhibited by most infectious diseases in the human body.

1. incubation period

2. prodromal stage

3. stage of illness

4. stage of decline

5. convalescence period


98. A healthcare-associated infection (traditionally known as nosocomial infection) is

A) acquired during the course of hospitalization

B) always present, but is inapparent at the time of hospitalization

C) only a result of surgery

D) always caused by medical personnel

Answer: A


99. Biological transmission differs from mechanical transmission in that biological transmission

A) occurs when a pathogen is carried on the feet of an insect

B) requires direct contact

C) involves reproduction of a pathogen in an arthropod vector prior to transmission

D) works only with noncommunicable diseases

Answer: C


100. Which of the following definitions is INCORRECT?

A) pandemic: a disease that affects a large number of people in the world in a short time

B) epidemic: a disease that is constantly present across the world

C) endemic: a disease that is constantly present in a population

D) incidence: number of new cases of a disease

Answer: B


101. The rise in herd immunity amongst a population can be directly attributed to:

A) antibiotic-resistant microorganisms

B) increased use of antibiotics

C) improved handwashing

D) vaccinations

Answer: D


102. Transient microbiota differs from normal microbiota in that transient microbiota

A) are present for a relatively short time

B) are always acquired by direct contact

C) never cause disease

D) are found in a certain location on the host

Answer: A


103. Which of the following is NOT a reservoir of infection?

A) None of the answers is correct; all of these can be reservoirs of infection

B) a healthy person

C) a hospital

D) a sick animal

Answer: A


104. The science that deals with when diseases occur and how they are transmitted is called

A) epidemiology

B) communicable disease

C) public health

D) ecology

Answer: A

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105. Figure 14.1 shows the incidence of influenza during a typical year. Which letter on the graph indicates the endemic level?

A) C

B) B

C) D

D) A

Answer: D


106. Would you expect the graph you saw in figure 14.1 to change if this was for the southern hemisphere, rather than the northern hemisphere?

A) Yes, because the population in the northern hemisphere is less than that in the southern hemisphere, the peak of the graph would be higher

B) Yes, because the seasons are reversed in the southern hemisphere. While weather doesn't directly cause influenza outbreaks, the cold, dry air and human crowding indoors contribute to increased cases. The southern hemisphere would still have a peak, but it would be at a different time of year than the northern hemisphere.

C) No, the graph would not change. Influenza epidemics occur at the same time each year.

Answer: B


107. Emergence of infectious diseases can be attributed to all of the following EXCEPT

A) The emergence of infectious diseases can be attributed to all of these.

B) Ease of travel

C) new strains of previously known agents

D) antibiotic resistance

Answer: A


108. Which of the following can contribute to postoperative infectors?

A) normal microbiota on the operating room staff

B) All of the answers are correct.

C) errors in aseptic technique

D) antibiotic resistance

Answer: B


109. The entry, establishment, and multiplication of a pathogen in a host is called:

A) exposure

B) inflammation

C) disease

D) infection

Answer: D


110. True or False? Phagocytosis is a form of adaptive immunity in the body.

A) True

B) False

Answer: B


111. On average, how long does it take the adaptive immune response to become fully active to an infecting pathogen?

A) 10 to 14 days

B) 2 to 3 days

C) 28 to 30 days

D) 18 to 24 hours

Answer: A


112. ______ are the natural reservoir for the Ebola virus.



113. Define the terms "vector" and "zoonotic".

vector is any agent which carries and transmits an infectious pathogen into another living organism

zoonotic disease is a disease or infection that can be transmitted naturally from animals to humans or from humans to animals


114. Why is Zika virus of great concern to pregnant women?

Zika virus is of great concern to pregnant women because the virus can spread to their babies which is linked to microcephaly.


115. Which of the following diseases has a commonly used vaccine that has dramatically reduced its occurrence? (for which, we discovered in class, I am too old and the vaccine was not available when I was younger)

A) herpes

B) chickenpox

C) ebola

D) zika virus infection

Answer: B


116. Explain how the terms COVID-19, SARS-CoV-2, and coronavirus mean different things.

SARS-CoV-2 - responsible for causing the disease.
Coronavirus - a family of viruses that include SARS-CoV-2.
COVID-19 - the actual name of the disease that is caused by SARS-CoV-2


117. The major significance of Robert Koch's work is that

A) microorganisms are the result of disease

B) microorganisms cause disease

C) diseases can be transmitted from one animal to another

D) microorganisms can be cultured

Answer: B


118. The SARS-CoV-2 virus has an RNA genome made of 30,000 nucleotides. List the four different types of nucleotides found in the SARS-CoV-2 genome.

A, U, C, and G


119. Under what circumstances it difficult to use Koch's postulates to determine the etiologic agent of an infectious disease?

The particular bacteria cannot be "grown in pure culture" in the laboratory