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Final Exam!

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569 Questions

Which stain (from a list) would be helpful in determining the size and shape of a colorless bacterium WITHOUT fixing.

India ink stain or Nigrosin stain

In a Gram stain, a step could be ommitted and still alllow differentiation between Gram positive and Gram negative cells. Which step?

Counterstaining with safranin or basic fuchsin

Which is NOT a type of inclusion (from a list)?

Ribosomes

How can genomes from microbes that cannot be grown in the lab still be studied?

Metagenomics

Six Staphylococcus aureus cells were accidently inoculated into an uncooked pie. How many cells would be in the pie after 3 hours. Assume generation time of 60 minutes.

48 cells

If an F+, Cys+ cell recombines with an F-, Cys- cell, what might happen to the F-,Cys- cell?

The recipient cell becomes F+ and Cys+

During PCR, instead of using DNA polymerase from Thermus aquaticus, human DNA polymerase is used. Starting with 1 molecule of DNA, after 3 full cycles are completed (assuming all other conditions remain the same), how many DNA molecules do you expect to see?

8 molecules

How did the idea of spontaneous generation come about?

The belief that living organisms emerge from nonliving matter arose from observations such as flies emerging from manure, maggots from dead animals, and microorganisms appearing in liquids after a short period.

What role do microorganisms play in the biological control of pests?

Certain microorganisms cause diseases in insects. Microorganisms that kill insects can be effective biological control agents because they are specific for the pest and do not persist in the environment.

What is the role do microorganisms play in recycling elements?

All of the above.

What role do microorganisms play in normal microbiota?

Normal microbiota are microorganisms that are found in and on the human body. They do not usually cause disease and can be beneficial.

What role do microorganisms play in sewage treatment?

Organic matter in sewage is decomposed by bacteria into carbon dioxide, nitrates, phosphates, sulfate, and other inorganic compounds in a wastewater treatment plant.

What role do microorganisms play in human insulin production?

Recombinant DNA techniques have resulted in insertion of the gene for insulin production into bacteria. These bacteria can produce human insulin inexpensively.

What role does microorganisms play in vaccine production?

Microorganisms can be used as vaccines. Some microbes can be genetically modified to produce components of vaccines.

What role do microorganisms play in biofilms?

Biofilms are aggregated bacteria adhering to each other and to a solid surface.

Match the microorganisms in column A to their descriptions in column B.

Archaea = Prokaryote without peptidoglycan cell wall Algae = Cell wall made of cellulose; photosynthetic Bacteria = Cell wall made of peptidoglycan Fungi = Cell wall made of chitin

Match the microorganisms in column A to their descriptions in column B.

Helminths = Multicellular animals Protozoa = Unicellular, complex cell structure lacking a cell wall Viruses = Not composed of cells

What type of microorganism has a peptidoglycan cell wall, has DNA that is not contained in a nucleus, and has flagella?

Bacterium

Where airborne microbes ended up in Pasteur’s experiment?

A

Which of the following is a scientific name?

Mycobacterium tuberculosis

Which of the following is not a characteristic of bacteria?

have the same shape

Which of the following is the most important element of Koch’s germ theory of disease? The animal shows disease symptoms when

a microorganism is inoculated into the animal.

Recombinant DNA is

the DNA resulting when genes of two different organisms are mixed.

Which of the following statements is the best definition of biogenesis?

Living cells can only arise from preexisting cells.

Which of the following is a beneficial activity of microorganisms?

all of the above

all of the above

It has been said that bacteria are essential for the existence of life on Earth. Which of the following is the essential function performed by bacteria?

decompose organic material and recycle elements

Which of the following is an example of bioremediation?

application of oil-degrading bacteria to an oil spill

Spallanzani’s conclusion about spontaneous generation was challenged because Antoine Lavoisier had just shown that oxygen was the vital component of air. Which of the following statements is true?

Some microbes do not require air.

Which of the following statements about E. coli is false?

E. coli was the first disease-causing bacterium identified by Koch.

How did the theory of biogenesis lead the way for the germ theory of disease?

By disproving spontaneous generation

Even though the germ theory of disease was not demonstrated until 1876, why did Semmelweis (1840) and Lister (1867) argue for the use of aseptic techniques?

They both discovered that when they practiced the cleaning of these tools and hands, that less and less people started dying.

Should antibacterial soaps and detergents be used in the home?

No, they contribute to antibiotic resistance and may harm the environment.

Which is NOT an emerging pathogen as described in your text.

All of the Above

Recombinant DNA technology has become an increasingly important part of our life. It is used for all of the following EXCEPT

synthesis of water.

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

use of genetically modified foods.

Which of the following is the best definition of oxidative phosphorylation?

A proton gradient allows hydrogen ions to flow back into the cells through transmembrane protein channels, releasing energy that is used to generate ATP.

In the figure, where is ATP produced?

E

Which of the following statements is INCORRECT regarding prokaryotic cells?

They lack a plasma membrane.

Which of the following statements regarding metabolism is FALSE?

Anabolic reactions are degradative.

Which of the following pairs is mismatched?

safranin – acid dye

All of the below are examples of a biofilm EXCEPT

archaea as part of the plankton community in the open ocean.

In non-cyclic photophosphorylation, excited electrons ultimately

combine with hydrogens ions and NADP+ to produce NADPH

Functions of the glycocalyx include all of the following EXCEPT

binary fission.

A microorganism measures 5 μm in length. What is its length in mm, nm, and m?

0.005 mm (millimeters) 5000 nm (nanometers) 5×10^-6m (meters)

Which type of microscope would be best to use to observe a stained bacterial smear

Compound light microscope

Which type of microscope would be best to use to observe unstained bacterial cells: the cells are small, and no detail is needed

Darkfield microscope

Which type of microscope would be best to use to observe unstained live tissue when it is desirable to see some intracellular detail?

Phase-contrast microscope

Which type of microscope would be best to use to observe a sample that emits light when illuminated with ultraviolet light?

Fluorescence microscope

Which type of microscope would be best to use to observe intracellular detail of a cell that is 1 μm long?

Electron microscope

Which type of microscope would be best to use to observe unstained live cells in which intracellular structures are shown in color?

Differential interference contrast microscope

Label the parts of the compound light microscope in the figure below, and then draw the path of light from the illuminator to your eye.

a = Ocular Lens b = Objective Lens c = Condenser Lens d = Diaphragm

Calculate the total magnification of the nucleus of a cell being observed through a compound light microscope with a 10× ocular lens and an oil

1000X

The maximum magnification of a compound microscope is

1500X

The maximum magnification of an electron microscope

10,000,000X

The maximum resolution of a compound microscope is

0.2 μm

The maximum resolution of an electron microscope

10 pm

One advantage of a scanning electron microscope over a transmission electron microscope is

Seeing three-dimensional detail.

In a hypertonic solution, what is likely to happen to a protoplast?

Water will diffuse out of the protoplast.

What is the fate of pyruvic acid in an organism that uses aerobic respiration?

It is converted into acetyl-CoA.

An enzyme, citrate synthase, is inhibited by ATP. This is an example of:

Feedback Inhibition

Given a "recipe" for a specific culture medium, identify a complex or defined medium.

Beef Nutrient Agar = Complex Medium Chicken Nutrient Agar = Complex Medium Glucose = Defined Medium K2HPO4 = Defined Medium

Which of the following disinfectants from a given list acts by disrupting the plasma membrane?

bisphenols

Which chemical method of microbial control damage DNA?

Aldehydes

Repeating sequences of non-coding DNA that are used for forensic analysis is called

Short Tandem Repeats (STRs)

If tryptophan is present, the repressible operon is:

Repressor becomes inactive

What are key features of a restriction enzyme?

All of the above

How is cDNA made?

made from mRNA by reverse transcription can be cloned in genomic libraries.

Why is a mordant used in the Gram stain?

In a Gram stain, the mordant combines with the basic dye to form a complex that will not wash out of gram-positive cells.

Why is a mordant used in the flagella stain?

In a flagella stain, the mordant accumulates on the flagella so that they can be seen with a light microscope.

What is the purpose of a counterstain in the acid-fast stain?

A counterstain stains the colorless non–acid-fast cells so that they are easily seen through a microscope.

What is the purpose of a decolorizer in the Gram stain?

In the Gram stain, the decolorizer removes the color from gram-negative cells.

What is the purpose of a decolorizer in the acid-fast stain?

In the acid-fast stain, the decolorizer removes the color from non–acid-fast cells.

Assume you stain Bacillus by applying malachite green with heat and then counterstain with safranin. Through the microscope, the green structures are

endospores.

Three-dimensional images of live cells can be produced with

confocal microscopy.

Carbolfuchsin can be used as a simple stain and a negative stain. As a simple stain, the pH is

higher than the negative stain.

Looking at the cell of a photosynthetic microorganism, you observe the chloroplasts are green in brightfield microscopy and red in fluorescence microscopy. You conclude:

chlorophyll is fluorescent.

Which of the following is not a functionally analogous pair of stains?

nigrosin and malachite green

Which of the following pairs is mismatched?

none of the above

Assume you stain Clostridium by applying a basic stain, carbolfuchsin, with heat, decolorizing with acid-alcohol, and counterstaining with an acidic stain, nigrosin. Through the microscope, the endospores are 1, and the cells are stained 2.

1—red; 2—colorless

Assume that you are viewing a Gram-stained field of red cocci and blue rods through the microscope. You can safely conclude that you have

two different species.

In 1996, scientists described a new tapeworm parasite that had killed at least one person. The initial examination of the patient’s abdominal mass was most likely made using

brightfield microscopy.

Which of the following is not a modification of a compound light microscope?

electron microscopy

In a Gram stain, a step could be omitted and still allow differentiation between gram-positive and gram-negative cells. What is it?

The counterstain (safranin) step

Using a good compound light microscope with a resolving power of 0.3 μm, a 10× ocular lens, and a 100× oil immersion lens, would you be able to discern two objects separated by 3 μm? 0.3 μm? 300 nm?

All of the Above

Endospores can be seen as refractile structures in unstained cells and as colorless areas in Gram-stained cells. Why is it necessary to do an endospore stain to verify the presence of endospores?

All of the above

In 1882, German bacteriologist Paul Erhlich described a method for staining Mycobacterium and noted, “It may be that all disinfecting agents which are acidic will be without effect on this [tubercle] bacillus, and one will have to be limited to alkaline agents.” How did he reach this conclusion without testing disinfectants?

By observing the acid-fast staining properties of Mycobacterium

Which of the graphs in the figure best illustrates the activity of an enzyme that is saturated with substrate?

c

Cyanobacteria are a type of

photoautotroph.

Which compound is being reduced in the reaction shown in the figure?

NAD+

An enzyme, citrate synthase, in the Krebs cycle is inhibited by ATP. This is an example of all of the following EXCEPT

competitive inhibition.

Microorganisms are involved in each of the following processes EXCEPT

smog production.

Microorganisms that catabolize sugars into ethanol and hydrogen gas would most likely be categorized as

heterolactic fermenters.

Which of the following statements about gram-negative cell walls is FALSE?

They are sensitive to penicillin.

Which of the following is not a distinguishing characteristic of prokaryotic cells?

They lack a plasma membrane.

Which statement best describes what happens when a gram-positive bacterium is placed in distilled water and penicillin?

The cell will undergo osmotic lysis.

Which statement best describes what happens when a gram-negative bacterium is placed in distilled water and penicillin?

Water will move into the cell.

Which statement best describes what happens when a gram-positive bacterium is placed in an aqueous solution of lysozyme and 10% sucrose?

No change will result; the solution is isotonic.

Which of the following statements best describes what happens to a cell exposed to polymyxins that destroy phospholipids?

Intracellular contents will leak from the cell.

Which of the following is false about fimbriae?

They may be used for motility.

Which of the following pairs is mismatched?

pili—reproduction

You have isolated a motile, gram-positive cell with no visible nucleus. You can assume this cell has

ribosomes.

The antibiotic amphotericin B disrupts plasma membranes by combining with sterols; it will affect all of the following cells except

gram-negative bacterial cells.

Endospore formation is called

sporogenesis

Endospore formation is initiated by

certain adverse environmental conditions

Formation of a new cell from an endospore is called

germination

Germination is triggered by

favorable growth conditions

Match the structures in column A to their functions in column B.

Cell Wall = Protection from osmotic lysis Endospore = Resting Fimbriae = Attachment to surfaces Flagella = Motility

Match the structures in column A to their functions in column B

Glycocalyx = Attachment to surfaces and Protection from phagocytes Pili = Motility and Transfer of genetic material Plasma membrane = Cell wall formation and Selective permeability Ribosomes = Protein synthesis

Why is an endospore called a resting structure?

because it provides a method for one cell to “rest,” or survive, as opposed to grow and reproduce.

Of what advantage is an endospore to a bacterial cell?

The protective endospore wall allows a bacterium to withstand adverse conditions in the environment.

Compare and Contrast simple diffusion and facilitated diffusion.

Both allow materials to cross the plasma membrane from a high concentration to a low concentration without expending energy. Facilitated diffusion requires carrier proteins.

Compare and contrast active transport and facilitated diffusion

Both require enzymes to move materials across the plasma membrane. In active transport, energy is expended.

Compare and contrast active transport and group translocation

Both move materials across the plasma membrane with an expenditure of energy. In group translocation, the substrate is changed after it crosses the membrane.

Why does penicillin have no effect on most gram-negative cells?

The outer layer of the gram-negative cells prevents penicillin from entering the cells.

How can prokaryotic cells be smaller than eukaryotic cells and still carry on all the functions of life?

Prokaryotic cells lack membrane-bound organelles, relying on a simpler internal structure with components freely floating in the cytoplasm.

Which of the following is NOT a functionally analogous pair?

cilia - pili

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

active transport

Robert Koch identified the cause of

anthrax.

A virus measures 100 nm in length. What is its length in μm?

0.1 μm

Which of the following uses glucose for carbon and energy?

chemoheterotroph

Which statements correspond to amphibolic pathways?

  1. Anabolic and catabolic reactions are joined through common intermediate.
  2. They are shared metabolic pathways.
  3. Feedback inhibition can help regulate rates of reactions.
  4. Both types of reactions are necessary but do not occur simultaneously.

1, 2, 3

Which drawing in the figure is streptococci?

d

Which microscope is used to see internal structures of cells in a natural state?

phase-contrast microscope

Which of the following is NOT found or observed to occur in both mitochondria and prokaryotes?

cell wall

Which microscope takes advantage of differences in the refractive indexes of cell structures?

phase-contrast microscope

Which two staining techniques employ a mordant?

Gram stain; Flagella stain.

Who challenged the idea of spontaneous generation with the concept of biogenesis?

Rudolf Virchow

Which of the following statements about anaerobic respiration is FALSE?

It involves the reduction of an organic final electron acceptor.

Differentiate the terms in each of the following pairs: etiology and pathogenesis

Etiology is the study of the cause of a disease, whereas pathogenesis is the manner in which the disease develops.

The emergence of new infectious diseases is probably due to all of the following except

the need of bacteria to cause disease.

All members of a group of ornithologists studying barn owls in the wild have had salmonellosis (Salmonella gastroenteritis). One birder is experiencing her third infection. What is the most likely source of their infections?

They are contaminating their hands while handling the owls and nests.

Which of the following statements is false?

E. coli never causes disease.

Which of the following is not one of Koch’s postulates?

The disease must be transmitted from a diseased animal to a healthy, susceptible animal by direct contact.

Which one of the following diseases is not correctly matched to its reservoir?

anthrax—nonliving

On September 6, a 6-year-old boy experienced fever, chills, and vomiting. On September 7, he was hospitalized with diarrhea and swollen lymph nodes under both arms. On September 3, the boy had been scratched and bitten by a cat. The cat was found dead on September 5, and Yersinia pestis was isolated from the cat. Chloramphenicol was administered to the boy from September 7, when Y. pestis was isolated from him. On September 17, the boy’s temperature returned to normal; and on September 22, he was released from the hospital.

identify the incubation period for this case of bubonic plague.

September 3–5

On September 6, a 6-year-old boy experienced fever, chills, and vomiting. On September 7, he was hospitalized with diarrhea and swollen lymph nodes under both arms. On September 3, the boy had been scratched and bitten by a cat. The cat was found dead on September 5, and Yersinia pestis was isolated from the cat. Chloramphenicol was administered to the boy from September 7, when Y. pestis was isolated from him. On September 17, the boy’s temperature returned to normal; and on September 22, he was released from the hospital.

Identify the prodromal period for this disease.

September 6–7

A Maryland woman was hospitalized with dehydration; Vibrio cholerae and Plesiomonas shigelloides were isolated from the patient. She had neither traveled outside the United States nor eaten raw shellfish during the preceding month. She had attended a party 2 days before her hospitalization. Two other people at the party had acute diarrheal illness and elevated levels of serum antibodies against Vibrio. Everyone at the party ate crabs and rice pudding with coconut milk. Crabs left over from this party were served at a second party. One of the 20 people at the second party had onset of mild diarrhea; specimens from 14 of these people were negative for vibriocidal antibodies.

This is an example of

vehicle transmission.

A Maryland woman was hospitalized with dehydration; Vibrio cholerae and Plesiomonas shigelloides were isolated from the patient. She had neither traveled outside the United States nor eaten raw shellfish during the preceding month. She had attended a party 2 days before her hospitalization. Two other people at the party had acute diarrheal illness and elevated levels of serum antibodies against Vibrio. Everyone at the party ate crabs and rice pudding with coconut milk. Crabs left over from this party were served at a second party. One of the 20 people at the second party had onset of mild diarrhea; specimens from 14 of these people were negative for vibriocidal antibodies.

The etiologic agent of the disease is

Vibrio cholerae

A Maryland woman was hospitalized with dehydration; Vibrio cholerae and Plesiomonas shigelloides were isolated from the patient. She had neither traveled outside the United States nor eaten raw shellfish during the preceding month. She had attended a party 2 days before her hospitalization. Two other people at the party had acute diarrheal illness and elevated levels of serum antibodies against Vibrio. Everyone at the party ate crabs and rice pudding with coconut milk. Crabs left over from this party were served at a second party. One of the 20 people at the second party had onset of mild diarrhea; specimens from 14 of these people were negative for vibriocidal antibodies.

The source of the disease was

crabs

Differentiate the terms in each of the following pairs: infection and disease

Infection refers to the colonization of the body by a microorganism. Disease is any change from a state of health. A disease may, but does not always, result from infection.

Differentiate the terms in each of the following pairs: communicable disease and noncommunicable disease

A communicable disease is a disease that is spread from one host to another, whereas a noncommunicable disease is not transmitted from one host to another.

Match

symbiosis (encompasses them all) = unlike organisms living together (Ex. coral and zooxanthellae) commensalism = one of the organisms benefits and the other is unaffected (Ex.corynebacteria living on the surface of the eye) mutualism = both organisms benefit (Ex. E. coli receives nutrients and a constant temperature in the large intestine and produces vitamin K and certain B vitamins that are useful for the human host.) parasitism = one organism benefits while the other is harmed(Ex. Salmonella enterica receives nutrients and warmth in the large intestine, and the human host experiences gastroenteritis or typhoid fever.)

Indicate whether each of the following conditions is typical of subacute, chronic, or acute infections.

Subacute = The patient has no apparent symptoms and is a known carrier. Chronic = The patient experiences cough and breathing difficulty for months. Acute Infections = The patient experiences a rapid onset of malaise; symptoms last 5 days.

Among hospital patients who have infections, one-third did not enter the hospital with the infection but rather acquired it in the hospital. How do they acquire these infections?

Hospital patients may be in a weakened condition and therefore predisposed to infection.

Among hospital patients who have infections, one-third did not enter the hospital with the infection but rather acquired it in the hospital. What is the method of transmission of these infections?

Pathogenic microorganisms are generally transmitted to patients by contact and airborne transmission.

Among hospital patients who have infections, one-third did not enter the hospital with the infection but rather acquired it in the hospital. What is the reservoir of infection?

The reservoirs of infection are the hospital staff, visitors, and other patients.

Distinguish symptoms from signs as signals of disease.

Symptoms = Changes in body function that the patient feels Signs = Objective changes that the physician can observe and measure Symptoms = weakness or pain are not measurable by a physician.

How can a local infection become a systemic infection?

When microorganisms causing a local infection enter a blood or lymph vessel and are spread throughout the body, a systemic infection can result.

Why are some organisms that constitute the normal microbiota described as commensals, whereas others are described as mutualistic?

Mutualistic microorganisms are providing a chemical or environment that is essential for the host. Commensal organisms are not essential; another microorganism might serve the function as well.

Put the following in the correct order to describe the pattern of disease: period of convalescence, prodromal period, period of decline, incubation period, period of illness.

Incubation period, prodromal period, period of illness, period of decline (may be crisis), period of convalescence.

Ten years before Robert Koch published his work on anthrax, Anton De Bary showed that potato blight was caused by the alga Phytophthora infestans. Why do you suppose we use Koch’s postulates instead of something called “De Bary’s postulates”?

Koch's postulates provided a method to link specific microorganisms to diseases, while De Bary's work on potato blight lacked a general method for identifying the causes of infections.

Name the method of transmission of each of the following diseases:

malaria = Mosquito tuberculosis = Air via respiratory droplets salmonellosis = contaminated food or water, often through the consumption of undercooked or raw foods. streptococcal pharyngitis = respiratory droplets or direct contact with respiratory secretions

Name the method of transmission of each of the following diseases:

mononucleosis = close contact with saliva, such as kissing or sharing utensils, measles = respiratory droplets when an infected person coughs or sneezes. Hepatitis A = ingestion of contaminated food or water, or through close contact with an infected person's stool. Tetanus = contamination of wounds with the spores of the bacterium Clostridium tetani

Name the method of transmission of each of the following diseases:

Hepatitis B = Transmitted through exposure to infected blood, semen, or other body fluids Chlamydial urethritis = sexual contact

=

Three days before a nurse developed meningococcemia, she assisted with intubation of a patient with a Neisseria meningitidis infection. Of the 24 medical personnel involved, only this nurse became ill. The nurse recalled that she was exposed to nasopharyngeal secretions and did not receive antibiotic prophylaxis. What two mistakes did the nurse make?

Not wearing a mask and not taking an antibiotic

Three days before a nurse developed meningococcemia, she assisted with intubation of a patient with a Neisseria meningitidis infection. Of the 24 medical personnel involved, only this nurse became ill. The nurse recalled that she was exposed to nasopharyngeal secretions and did not receive antibiotic prophylaxis. How is meningitis transmitted?

Meningitis is the bacterial disease that can be transmitted through nasal and oral secretions -like coughing and sneezing. It is not highly contagious.

Which of the following statements concerning pathology, infection, and disease is true?

Pathology refers to the study of structural and functional changes that occur in the body as a result of a disease.

Which of the following is an example of the symbiotic relationship known as mutualism?

E. coli within the large intestine

Koch's postulates established criteria for proving that a specific organism causes a specific disease. Which of the following is NOT one of the criteria given by Koch's postulates?

The pathogen must be isolated from inoculated animals and must be different from the original organism.

Which of the following is classified as a latent disease?

shingles

Which of the following statements about the development of infectious diseases is correct?

The period of convalescence is the time during which the person regains health and fully recovers (back to the pre-disease state).

Which of the following is a protozoan zoonosis that can be transmitted by direct contact?

Toxoplasmosis

Which of the following would be an example of disease transmission via indirect contact?

A student sneezes on her test booklet. The instructor grades it and catches her cold.

As a health care worker, you are keenly aware of how important it is to avoid harming patients. You worry about inadvertently transmitting an infectious disease to an already compromised individual. According to the CDC, what is the most important thing you can do to avoid this?

wash my hands before and after interacting with any patient

The following choices list several types of diseases, along with factors that may contribute to their emergence. Which disease and associated factor do NOT match?

emergence of avian influenza A (H5N1); use of antibiotics

Match

Etiology = The study of the cause of a disease Infectious Disease = Disease directly caused by microorganisms and nit by other means, for example, genetic or degenerative diseases Germ Theory of Disease = This theory states that microorganisms cause infectious disease Koch's Postulates = Experimental requirements for identifying the agent of an infectious disease

Match

Diseased or Dead Animal = Original source of the infectious microbial agent Healthy Laboratory Animal = Organism injected with a potential infectious agent Microscope = Tool used to view and identify individual microorganism Growth Media = Nutrient-rich environment for isolating and culturing microorganisms

Which statements accurately describe Koch’s postulates?

ALL OF THE ABOVE

This activity presents experimental results obtained when a suspected pathogen was tested and asks you to identify appropriate conclusions based on each scenario.

A rabbit was found to have floppy ear disease, which causes long-ear infections. Its etiology (cause) is unknown. Unknown Microorganism X from the infected rabbit’s right ear is successfully isolated and cultured on laboratory growth media. The ear of a healthy laboratory mouse is then inoculated with isolated microorganism, and after a period of time, no disease is observed. Which of the following statements accurately describe(s) the conclusion(s) that can be drawn from this experiment?

Microorganism X modified its cell wall structure while being cultured, and is no longer infectious to rabbits. = Not an Accurate Conclusion Healthy laboratory organisms rarely show signs and symptoms of infection and disease. = Not an Accurate Conclusion A laboratory mouse might not be an appropriate, susceptible host; an experiment with a laboratory rabbit may be needed. = Accurate Conclusion Microorganism X might not be linked to floppy ear disease, because the inoculated mouse remained healthy. = Accurate Conclusion

Match

Benefit = The steps are designed to systematically link a pathogen to a specific infectious disease Benefit = Laboratory findings provide experimental evidence that support the germ theory of disease Limitation = Some infectious agents have specific growth requiements that prevent them from being artificially cultured in the laboratory Limitation = Different pathogens can be produce the same signs and symptoms, making it difficult to determine which microorganism is causing a disease

Match

Benefit = Healthy, suspectiable animals can be used as modell organisms for testing many types of infections, thus avoiding the unethical inoculation of healthy human hosts Limitation = Some pathogens cause several different diseases, which makes it difficult to link one pathogen to one disease using Koch's postulates

=

During a six-month period, 239 cases of pneumonia occurred in a town of 300 people. A clinical case was defined as fever ≥ 39°C lasting >2 days with three or more symptoms (i.e., chills, sweats, severe headache, cough, aching muscles/joints, fatigue, or feeling ill). A laboratory-confirmed case was defined as a positive result for antibodies against Coxiella burnetii. Before the outbreak, 2000 sheep were kept northwest of the town. Of the 20 sheep tested from the flock, 15 were positive for C. burnetii antibodies. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years.

The etiologic agent of the disease in the situation is

Coxiella burnetii

A commensal bacterium

may also be an opportunistic pathogen.

One effect of washing regularly with antibacterial agents is the removal of normal microbiota. This can result in

increased susceptibility to disease.

The major significance of Robert Koch's work is that

microorganisms cause disease.

Focal infections initially start out as

local infections.

Malaria is an infectious disease caused by infection with a protozoan. In certain tropical regions, malaria is constantly present. We would say that malaria is a(n) __________ disease in these regions.

endemic

Symptoms of disease differ from signs of disease in that symptoms

are changes felt by the patient.

Which of the following definitions is INCORRECT?

secondary infection: a long-lasting illness

The CDC is located in

Atlanta, GA.

A researcher has performed a prospective study on a disease. To which specific kind of epidemiological study is this referring?

descriptive

Which advance (from a list) occured during the Second Golden Age of Microbiology?

All of the Above

Which advance (from a list) occured during the Second Golden Age of Microbiology?

All of the Above

Which advance (from a list) occured during the Second Golden Age of Microbiology?

ALL OF THE ABOVE

Which substance in the following reaction is being reduced?

acetaldehyde

Which of the following reactions produces the most molecules of ATP during aerobic metabolism?

acetyl CoA → CO2 + H2O

Which of the following processes does not generate ATP?

the Calvin-Benson cycle

Which of the following compounds has the greatest amount of energy for a cell?

glucose

Which of the following is the best definition of the Krebs cycle?

a series of chemical reactions in which NADH is produced from the oxidation of pyruvic acid

Which of the following is the best definition of respiration?

a sequence of carrier molecules with the final electron acceptor from the environment

Which culture produces the most lactic acid?

E. coli growing in glucose broth at 35°C without O2 for 5 days

Which culture produces the most ATP?

E. coli growing in glucose broth at 35°C with O2 for 5 days

Which culture uses NAD+?

both a and b

Which culture uses the most glucose?

E. coli growing in glucose broth at 35°C without O2 for 5 days

Define oxidation-reduction

A coupled reaction in which one substance loses electrons and another gains electrons.

What is the difference between aerobic and anaerobic?

The final electron acceptor in aerobic respiration is molecular oxygen; in anaerobic respiration, it is another inorganic molecule.

What is the difference between respiration and fermentation?

The final electron acceptor in respiration is usually inorganic; in fermentation it is usually organic.

What is the difference between cyclic and noncyclic photophosphorylation?

In cyclic photophosphorylation, electrons are returned to chlorophyll. In noncyclic photophosphorylation, chlorophyll receives electrons from hydrogen atoms.

All of the energy-producing biochemical reactions that occur in cells, such as photophosphorylation and glycolysis, are _____ reactions.

Oxidation

Match: What are their carbon sources?

Photoautotroph = CO2 Photoheterotroph = Light Chemoautotroph = Organic molecules Chemoheterotroph = Light

Match: What are their energy sources?

Photoautotroph = CO2 Photoheterotroph = Inorganic molecules Chemoautotroph = Organic molecules Chemoheterotroph = Organic molecules

Explain why, even under ideal conditions, Streptococcus grows slowly.

Mainly because they use anaerobic respiration thus produce only a little amount of ATP

Microorganisms placed in high concentrations of salts and sugars undergo lysis.

False

A population of cells carrying a desired plasmid is called a

clone.

Which of the following does NOT achieve sterilization?

pasteurization

A sample of milk is tested for its bacterial content in a plate count assay. A one-milliliter sample of the milk is diluted in a 1:10 dilution series. One milliliter of the third dilution tube is plated in a pour plate. After incubation, the plate has 54 colonies, indicating that the original milk sample contained

54,000 cells per milliliter.

Culture 1: F+, leucine+, histidine+ Culture 2: F-, leucine-, histidine-

In the table, if culture 1 mutates to Hfr, what will be the result of conjugation between the two cultures?

1 will remain the same; recombination may occur in 2

An experiment began with 4 cells in log phase and ended with 128 cells. How many generations did the cells go through?

5

Which enzyme catalyzes the following reaction? 2H2O2 → 2H2O + O2

catalase

The biosafety level (BSL) for most introductory microbiology laboratories is

BSL-1.

A culture medium consisting of agar, peptone, and beef heart is a

complex medium.

The term aerotolerant anaerobe refers to an organism that

does not use oxygen but tolerates it.

All of the following are effective for destroying prions EXCEPT

boiling.

An advantage of cDNA over genomic DNA is that it

lacks introns.

Which of the following could be used to sterilize plastic Petri plates in a plastic wrapper?

gamma radiation

Medium 1 is

both selective and differential.

Medium 2 is

selective

Which of the lines best depicts the log phase of a thermophile incubated at room temperature?

c

Which of the lines best depicts the log phase of Listeria monocytogenes growing in a human?

a

Assume you inoculated 100 facultatively anaerobic cells onto nutrient agar and incubated the plate aerobically. You then inoculated 100 cells of the same species onto nutrient agar and incubated the second plate anaerobically. After incubation for 24 hours, you should have

the same number of colonies on both plates.

The term trace elements refers to

small mineral requirements.

Which one of the following temperatures would most likely kill a mesophile?

60°C

Which of the following is not a characteristic of biofilms?

iron deficiency

Which of the following types of media would not be used to culture aerobes?

reducing media

An organism that has peroxidase and superoxide dismutase but lacks catalase is most likely an

aerotolerant anaerobe.

The ability of some microbes, such as Trypanosoma or Giardia to alter their surface molecules and evade destruction by the host's antibodies is called

antigenic variation.

Which of the following toxins and descriptions do NOT match?

Vibrio enterotoxin: a superantigen that destroys epithelial cells

Which of the following statements about exotoxins is generally FALSE?

They are resistant to heat.

Which of the following is NOT a cytopathic effect (CPE) of viruses?

All of the listed choices are possible cytopathic effects of viruses.

Which type of bacterial enzyme helps spread Streptococcus pyogenes by digesting blood clots?

fibrinolysin

Which statement regarding endotoxins is true?

One consequence of endotoxins is the activation of blood-clotting proteins.

In which of the following cases would the Limulus amebocyte lysate (LAL) assay be used?

to ensure that a sterilized medical device is free of endotoxin

Which of the following would be an example of an infection initiated via the parenteral route?

An individual contracts hepatitis B from an accidental stick with a contaminated needle.

Which of the following is an example of direct damage due to bacterial infection?

the invasion and lysis of intestinal cells by E. coli

All of the following contribute to a pathogen's invasiveness EXCEPT

toxins.

All of the following are methods of avoiding host antibodies EXCEPT

membrane-disrupting toxins.

A pathogen that is capable of antigenic variation can ________________.

avoid host immune defenses

Which of the following statements about adherence is true?

Most bacterial adhesins are glycoproteins or lipoproteins.

All of the following are used by bacteria to attach to host cells EXCEPT

A-B toxins.

The ID50 is

the dose that will cause an infection in 50 percent of the test population.

Ergot and aflatoxin are toxins sometimes found in grains contaminated with fungi.

True

Certain traits that allow pathogens to create infection and cause disease are termed

virulence factors.

Which of the following enzymes breaks down the "glue" that holds cells together?

Hyaluronidase

Which of the following virulence factors would be found in Staphylococcus aureus?

Staphylokinase

How do fibrinolysins enhance a pathogen's virulence?

They break down fibrin proteins that are involved in clot formation, allowing the cells to penetrate deep into damaged skin.

Siderophores are bacterial proteins that compete with the host's

iron-transport proteins.

Which of the following statements about lysogenic conversion is true?

Exotoxin production by bacteria is frequently the result of a lysogenic infection.

In mice, the LD50 for staphylococcal enterotoxin is 1350 ng/kg, and the LD50 for Shiga toxin is 250 ng/kg. Which of the following statements is true?

Shiga toxin is more lethal than staphylococcal enterotoxin.

Which of the following cytopathic effects is cytocidal?

release of enzymes from lysosomes

Antibiotics can lead to septic shock if used to treat

gram-negative bacterial infections.

The most frequently used portal of entry for pathogens is the

mucous membranes of the respiratory tract.

Symptoms of protozoan and helminthic diseases are due to

tissue damage due to growth of the parasite on the tissues, waste products excreted by the parasite, and products released from damaged tissues.

Most fungi grow best at pH

5

A suspension of 106 Bacillus cereus endospores was put in a hot-air oven at 170°C. Plate counts were used to determine the number of endospores surviving at the time intervals shown.

In the figure, the thermal death point for this culture is

The answer cannot be determined based on the information provided

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

biofilms develop on catheters.

If you knew the sequence of nucleotides within a gene, which one of the following could you determine with the most accuracy?

the primary structure of the protein

If you were preparing nutrient agar at home and did not have an autoclave, what could you use to sterilize the nutrient agar?

pressure cooker at 121°C for 15 minute

Which of the following best describes the pattern of microbial death?

The cells in a population die at a constant rate.

One advantage of a viral vector over a plasmid vector is that the

viral vector can accept much larger pieces of DNA.

A gene is defined as

a sequence of nucleotides in DNA that codes for a functional product.

The fact that people continue to be concerned about the safety of DNA technology can be attributed to the following:

Both that it is impossible to prove something is safe under all conditions and that science can only provide supporting evidence for hypotheses.

If cells are grown in media containing amino acids labeled with radioactive nitrogen (15N), most of the radioactivity will be found in the cells'

DNA and proteins.

Which of the following is NOT a desired characteristic of DNA vectors used in gene cloning procedures?

large size

In the figure, which line best depicts a facultative anaerobe in the absence of O2?

b

During which growth phase will gram-positive bacteria be most susceptible to penicillin?

log phase

The reaction catalyzed by reverse transcriptase is

mRNA → cDNA.

Which of the following is NOT a product of transcription?

a new strand of DNA

A kitchen countertop has a spill of vegetable oil that was wiped up but a film remains. What should be the next step in disinfecting this surface?

warm soapy scrub

Which of the following statements regarding a bacterium that is R+ is FALSE?

It is F+.

A source of heat-stable DNA polymerase is

Thermus aquaticus.

In the figure, which model of the lac operon correctly shows RNA polymerase, lactose, and repressor protein when the structural genes are being transcribed?

d

Which of the following pairs of terms is mismatched?

bacteriostatic – kills vegetative bacterial cells

Repair of damaged DNA, in some instances and mechanisms, might be viewed as a race between an endonuclease and

methylase.

Which of the following is NOT an agricultural product made by DNA techniques?

pectinase

According to the operon model, for the synthesis of an inducible enzyme to occur, the

substrate must bind to the repressor.

There have been several changes in taxonomy over the years. Who proposed the current taxonomy described in your text with three Domains (1978):

Woese

Use of culture independent techniques like rRNA sequencing and FISH increased our understanding of microbial diversity. Why should microbiologists still attempt to grow new species?

Yes, because there are many species yet to be discovered, mutations occur, exploration of new places leads to the possibility of new microbes

Gram-negative rods that are aerobic and non-fermenting:

non-fermenters or non-fermentative bacteria. or often opportunistic pathogens

In what ways has PrPSc NOT been transmitted?

Airborne transmission

What phyla do the Methanobacteria and Halobacteria belong to?

Euryarchaeota

During development of disease, what defines a short period after incubation; early, mild symptoms

Prodromal period

Of a list, which are factors that determine the distribution and composition of normal microbiota?

All of the Above

What are the exceptions to Koch's postulates?

All of the Above

A mosquito carrying the causative agent of malaria bites a human. What mode and type of transmission is this?

Arthropod vector transmission

Of a list, which epidemiologist is best described as using analytical epidemiology to address an issue?

Florence Nightingale

Incidence of a specific notifiable disease

All of the Above

Which describes infectious dose (given ID50 and LD50)?

The most infectious dose

What cell wall components prevent phagocytosis?

the M protein and waxy lipid (mycolic acid in Mycobacterium)

Compare exotoxins and endotoxins

Exotoxin = Secreted to the outside of the bacteria Endotoxin = Part of outer portion of cell wall in gram-negative bacteria Exotoxin = Most are proteins/enzymes Endotoxin = Most are lipids

Compare exotoxins and endotoxins

Endotoxin = Released during bacterial multiplication and lysis Endotoxin = Work by stimulating macrophages to release cytokines at toxic levels Exotoxin = Soluble in fluid and easily diffuses into the bloodstream Exotoxin = Produced by gram-negative or gram-positive bacteria

Compare exotoxins and endotoxins

Exotoxin = Produce specific signs and symptoms of disease Endotoxin = Produce fever

=

How do protozoa evade host defenses?

All of the Above

Which of the following exhibits the highest phagocytic activity?

macrophages

Which of the following are best described as short chains of amino acids that are very stable and can have a variety of different antimicrobial activities, such as forming pores in bacterial plasma membranes and inhibiting cell wall synthesis?

antimicrobial peptides

Each of the following provides protection from phagocytic digestion EXCEPT

formation of phagolysosomes.

Innate immunity

is nonspecific and present at birth.

Which statement regarding the lymphatic system is true?

Lymphatic capillaries possess one-way valves. These valves permit the uptake of fluid from the body but do not allow the fluid to flow back out of the capillaries into the intracellular spaces.

You note that the body temperature of one of your patients is starting to increase. As a result, you can infer that all of the following may be occurring in this patient EXCEPT __________.

dilation of blood vessels

Which of the following can defend the body by either opsonizing bacteria, lysing bacteria, and/or promoting inflammation?

Alpha and beta interferons

Normal microbiota provide resistance to disease in all of the following ways except __________________.

serving as prebiotics

All of the following increase blood vessel permeability EXCEPT

lysozymes.

All of the following pertain to fever EXCEPT that it

accelerates microbial growth by increasing iron absorption from the digestive tract.

Which of the following is an effect of opsonization?

increased adherence of phagocytes to microorganisms

Which of the following statements concerning phagocytosis is true?

Bacteria are digested when the phagosome fuses with a lysosome.

If one is examining a blood smear from a patient with a parasitic worm infection, which of the following leukocytes would be found in increased numbers?

eosinophils

Which non-specific defense mechanism is mismatched with its associated body structure or body fluid?

mucociliary escalator – intestines

All of the following protect the skin and mucous membranes from infection EXCEPT

HCl.

The lectin pathway for complement action is initiated by

mannose on the surface of microbes.

Which of the following statements about innate immunity is true?

Innate immunity is present at birth.

Lysozyme and the antibiotic penicillin have similar mechanisms of action in that they both cause damage to the bacterial

cell wall.

Which of the following statements about beta interferons is true?

It acts as a signal that induces uninfected cells to produce antiviral proteins.

Unbroken skin poses a substantial barrier to microbes. All of the following contribute to this barrier except

complement proteins found in perspiration

The complement protein cascade is the same for the classical pathway, alternative pathway, and lectin pathway after the point in the cascade where the activation of ________ takes place.

C3

Which of the following is mismatched?

chemotaxis – chemical degradation inside a phagolysosome

TLRs attach to all of the following EXCEPT

AMPs.

Which of the following statements is TRUE?

There are at least thirty complement proteins.

The thermal death time for a suspension of Bacillus subtilis endospores is 30 minutes in dry heat and less than 10 minutes in an autoclave. Which type of heat is more effective?

Autoclave

If pasteurization does not achieve sterilization, why is pasteurization used to treat food?

Because it destroys most organisms that cause disease or rapid spoilage of food.

Which factors can alter thermal death point?

All of the Above

The antimicrobial effect of gamma radiation is due to (a)____ . The antimicrobial effect of ultraviolet radiation is due to (b)___

(a) the ability of ionizing radiation to break DNA (b) formation of thymine dimers.

How do autoclaving, hot air, and pasteurization illustrate the concept of equivalent treatments?

All three processes kill microorganisms; however, as moisture and/or temperatures are increased, less time is required to achieve the same result.

How do salts and sugars preserve foods?

Salts and sugars create a hypertonic environment.

Name one food that is preserved with sugar and one preserved with salt.

Sugar = Jams and jellies Salt = Meats

=

The use-dilution values for two disinfectants tested under the same conditions are as follows: Disinfectant A—1:2; Disinfectant B—1:10,000. If both disinfectants are designed for the same purpose, which would you select?

Disinfectant B—1:10,000

Which of the following does not kill endospores?

pasteurization

Which of the following is most effective for sterilizing mattresses and plastic Petri dishes?

ethylene oxide

Which of these disinfectants does not act by disrupting the plasma membrane?

halogens

Which of the following cannot be used to sterilize a heat-labile solution stored in a plastic container?

autoclaving

Which of the following is used to control microbial growth in foods?

organic acids

Which disinfectant is the most effective?

A only

Which disinfectant(s) is (are) bactericidal?

A, C, and D

Which of the following is not a characteristic of quaternary ammonium compounds?

sporicidal

A classmate is trying to determine how a disinfectant might kill cells. You observed that when he spilled the disinfectant in your reduced litmus milk, the litmus turned blue again. You suggest to your classmate that

the disinfectant might oxidize molecules.

Which of the following is most likely to be bactericidal?

ionizing radiation

Which disinfectant was the most effective against the organism?

Disinfectant Z

Transfer of DNA from a donor to a recipient cell by a bacteriophage.

transduction

Transfer of DNA from a donor to a recipient as naked DNA in solution.

transformation

Feedback inhibition differs from repression because feedback inhibition

stops the action of preexisting enzymes.

Bacteria can acquire antibiotic resistance by all of the following except

snRNPs.

Suppose you inoculate three flasks of minimal salts broth with E. coli. Flask A contains glucose. Flask B contains glucose and lactose. Flask C contains lactose. After a few hours of incubation, you test the flasks for the presence of β-galactosidase. Which flask(s) do you predict will have this enzyme?

C

Plasmids differ from transposons in that plasmids

are self-replicated outside the chromosome.

Mechanism by which the presence of glucose inhibits the lac operon.

catabolite repression

The mechanism by which lactose controls the lac operon.

induction

Two offspring cells are most likely to inherit which one of the following from the parent cell?

a change in a nucleotide in DNA

Which of the following is not a method of horizontal gene transfer?

binary fission

Match the following examples of mutagens.

Frameshift mutagen = Nucleoside analog Nucleoside analog = Ionizing radiation Base-pair mutagen = Base-pair mutagen Ionizing radiation = Frameshift mutagen

Match the following examples of mutagens.

A mutagen that causes the formation of pyrimidine dimers = Nonionizing radiation A mutagen that is incorporated into DNA in place of a normal base = Frameshift mutagen

=

When iron is not available, E. coli can stop synthesis of all proteins, such as superoxide dismutase and succinate dehydrogenase, that require iron. Describe a mechanism for this regulation.

Iron deficiency could stimulate miRNA that is complementary to RNA encoding iron-requiring proteins

Why are mutation and recombination important in the process of natural selection and the evolution of organisms?

All of the above

Restriction enzymes were first discovered with the observation that

phage DNA is destroyed in a host cell.

The DNA probe, 3’-GGCTTA, will hybridize with which of the following?

5’-CCGAAT

Which of the following is the fourth basic step to genetically modify a cell?

ligation

The following enzymes are used to make cDNA. What is the second enzyme used to make cDNA?

ribozyme

If you put a gene in a virus, the next step in genetic modification would be

transduction.

You have a small gene that you want replicated by PCR. You add radioactively labeled nucleotides to the PCR thermal cycler. After three replication cycles, what percentage of the DNA single strands are radioactively labeled?

87.5%

Pieces of human DNA stored in yeast cells.

library

A population of cells carrying a desired plasmid.

clone

Self-replicating DNA for transmitting a gene from one organism to another.

vector

DNA that hybridizes with mRNA.

antisense

Which are DNA?

cDNA = DNA gene = DNA DNA probe = DNA rDNA = DNA

Of what value are sticky ends in making rDNA?

Fragments of DNA produced with the same restriction enzyme will spontaneously anneal to each other at their sticky ends

Which of the following organisms are most closely related?

A and D

Are any two the same species?

None of them are the same species

Which of these organisms are most closely related?

A and D are most closely related.

The GC content of Micrococcus is 66–75 moles %, and of Staphylococcus, 30–40 moles %. According to this information, would you conclude that these two genera are closely related?

No, they are not closely related

Describe the use of a DNA probe and PCR for: Rapid identification of an unknown bacterium and determining which of a group of bacterium are most closely related.

DNA Probe = give us library of known bacteria to compare unknown bacteria to on plate PCR = allows for replication and isolation of one strand of DNA to match to DNA probe DNA Probe = allows us to match enzymes from sample to determine molecular % PCR = allows for replication and isolation of one strand of DNA to match to DNA probe

Bergey’s Manual of Systematic Bacteriology differs from Bergey’s Manual of Determinative Bacteriology in that the former

groups bacteria according to phylogenetic relationships.

Bacillus and Lactobacillus are not in the same order. This indicates that which one of the following is not sufficient to assign an organism to a taxon?

morphological characteristics

Which of the following is used to classify organisms into the Kingdom Fungi?

absorptive; possess cell wall; eukaryotic

You could identify an unknown bacterium by all of the following except

percentage of guanine + cytosine.

The wall-less mycoplasmas are considered to be related to gram-positive bacteria . Which of the following would provide the most compelling evidence for this?

They share common rRNA sequences.

Into which group would you place a multicellular organism that has a mouth and lives inside the human liver?

Animalia

Into which group would you place a photosynthetic organism that lacks a nucleus and has a thin peptidoglycan wall surrounded by an outer membrane?

Proteobacteria (gram-negative bacteria)

Which is (are) found in all three domains?

  1. 9 + 2 flagella
  2. 70S ribosome
  3. fimbria
  4. nucleus
  5. peptidoglycan
  6. plasma membrane

2,6 (70S ribosome and plasma membrane)

Which is (are) found only in prokaryotes?

  1. 9 + 2 flagella
  2. 70S ribosome
  3. fimbria
  4. nucleus
  5. peptidoglycan
  6. plasma membrane

3, 5 (fimbria and peptidoglycan)

If you Gram-stained the bacteria that live in the human intestine, you would expect to find mostly

gram-negative rods.

Which of the following does not belong with the others?

Lactobacillales

Pathogenic bacteria can be

All of the Above

Which of the following is an intracellular parasite?

Rickettsia

Which of the following terms is the most specific?

bacillus

Which one of the following does not belong with the others?

Staphylococcus

Which of the following pairs is mismatched?

spirochete—Helicobacter

Spirillum is not classified as a spirochete because spirochetes

possess axial filaments.

When Legionella was newly discovered, why was it classified with the pseudomonads?

It is an aerobic gram-negative rod.

Unlike purple and green phototrophic bacteria, cyanobacteria

produce oxygen during photosynthesis.

Use of culture-independent techniques such as rRNA sequencing and FISH have increased our understanding of microbial diversity without cultivation. Do microbiologists still need to attempt to grow new species? Briefly explain.

Yes, because there are many species yet to be discovered, mutations occur, exploration of new places leads to the possibility of new microbes

To which of the following is the photosynthetic bacterium Chromatium most closely related? Briefly explain why.

Escherichia

After contact with a patient’s spinal fluid, a lab technician developed fever, nausea, and purple lesions on her neck and extremities. A throat culture grew gram-negative diplococci. What is the genus of the bacteria?

Neisseria meningitidis

Between April 1 and May 15 of one year, 22 children in three states developed diarrhea, fever, and vomiting. The children had each received pet ducklings. Gram-negative, facultatively anaerobic bacteria were isolated from both the patients’ and the ducks’ feces; the bacteria were identified as serovar C2. What is the genus of these bacteria?

Salmonella

A woman complaining of lower abdominal pain with a temper-ature of 39°C gave birth soon after to a stillborn baby. Blood cultures from the infant revealed gram-positive rods. The woman had a history of eating unheated hot dogs during her pregnancy. Which organism is most likely involved?

Listeria

Which of the following is NOT a characteristic of B cells?

They recognize antigens associated with MHC I.

In the figure, which areas are similar for all IgG antibodies?

c and d

Which of the following statements concerning immunological memory is true?

The memory response is due to production of long-lived memory cells that can respond very rapidly upon second exposure.

What type of immunity results from vaccination?

artificially acquired active immunity

What is the correct sequence of events for activation of a B cell by a T-dependent antigen?

(1) Immunoglobulin receptors on the B cell recognize and bind the antigen. (2) An antigen fragment in complex with MHC class 2 is displayed on the B cell's surface. (3) The MHC-antigen complex binds a receptor on a TH cell. (4) The TH cell secretes cytokines that activate the B cell.

Which type of T cell is involved in activating macrophages and stimulating development of cytotoxic T cells?

TH1 cells

Which of the following statements about cytokines is FALSE?

There are 10 types.

Consider a helminthic infection in which an individual is colonized by a parasitic worm. The worm is too big to be engulfed by a phagocytic cell. How does the immune system respond?

The worm gets coated with antibodies, which activate other cells in the immune system to secrete chemicals that kill it.

Which immunoglobulin class, found in blood, lymph, and the intestine, can cross the placenta and help to protect a fetus?

IgG

When an antibody binds to a toxin, the resulting action is referred to as

neutralization

Which of the following cells is NOT an APC?

natural killer cells

In the figure, what portion will typically attach to a host cell?

e

The antibodies found in mucus, saliva, and tears are

IgA.

Which of the following statements concerning antigen-presenting cells is true?

They are involved in activating T cells.

If a patient has been exposed to an antigen for the first time, which class of immunoglobulin appears first?

IgM

Which of the following is the best definition of epitope?

specific regions on antigens that interact with antibodies

The following events elicit an antibody response. What is the third step?

TH cell recognizes antigen-digest and MHC II.

Newborns' immunity due to the transfer of antibodies across the placenta is an example of

naturally acquired passive immunity.

Which of the following statements concerning cellular immunity is FALSE?

Cellular immunity involves cells that recognize antigens and make specific antibodies against them.

A Treg cell deficiency could result in

autoimmunity.

An individual may be exposed to a pathogen and become infected without actually getting sick. This is known as a subclinical infection. Even in subclinical infections, the individual's adaptive immune system can generate memory for the pathogen. What type of adaptive immunity is this?

naturally acquired active immunity

Which of the following is NOT a characteristic of cellular immunity?

B cells make antibodies

Which cytokines are believed to contribute to autoimmune disease, such as rheumatoid arthritis?

tumor necrosis factor (TNF)

CD4+ T cells are activated by

interaction between CD4+ and MHC II.

The following events occur in cellular immunity, leading to a response from TH cells. What is the third step?

TH cells proliferate.

Which of the following terms regarding roles of chemical messengers is mismatched?

tumor necrosis factor - stimulate tumor metastasis

What type of immunity results from recovery from mumps?

naturally acquired active immunity

Which of the following statements about members of the Kingdom Plantae is FALSE?

They use organic carbon sources.

A bacterial species differs from a species of eukaryotic organisms in that a bacterial species

is a population of cells with similar characteristics.

Fatty acid methyl ester analysis is commonly used

in bacterial identification.

In the table, which features are found in nearly all eukarya?

  1. 9+2 flagella
  2. Nucleus
  3. Plasma membrane
  4. Peptidoglycan
  5. Mitochondrion
  6. Fimbriae

2, 3, 5

Phage typing is based on the fact that

bacterial viruses attack only members of a specific species.

In a direct ELISA test, the method is determining if ________ is/are present in the patient's sample by attempting to bind a labeled antibody to it.

an antigen from a particular pathogen

This figure shows the results of a gel electrophoresis separation of restriction fragments of the DNA of different organisms. In the figure, which two are most closely related?

1 and 3

Into which group would you place a photosynthetic cell that lacks a nucleus?

Bacteria

Which of the following pairs is mismatched?

chemoautotrophic bacteria – fix atmospheric nitrogen

You have isolated an aerobic gram-positive, endospore-forming bacterium that grows well on nutrient agar. To which of the following groups does it most likely belong?

bacillales

Which of the following best describes the enterics, a bacterial group found primarily in the intestines of humans?

facultatively anaerobic gram-negative rods

Which of the following is NOT a characteristic of spirochetes?

easily observed with brightfield microscopy

The genus of bacteria that are particularly problematic in hospital settings due to their ability to grow in solutions with minute traces of unusual carbon sources is

Pseudomonas.

Actinomycetes differ from fungi in that actinomycetes

lack a membrane-bounded nucleus.

Staphylococcus and Streptococcus can usually be differentiated by microscope examination because of

cell arrangement.

Assume you have isolated a multicellular heterotrophic organism that produces coenocytic hyphae, motile zoospores, and cellulose cell walls. It is most likely a(n)

oomycote alga.

You observe a mass of amoeba-like cells that swarm together, form a stalk, and produce spores. This is a(n)

cellular slime mold.

Which of the following is the most effective control for malaria?

eliminate Anopheles mosquitoes

If a larva of Echinococcus granulosus is found in humans, humans are the

intermediate host.

Which of the following statements regarding lichens is FALSE?

Lichens are a mutualistic relationship between a fungus and a protozoan.

Which of the following pairs is mismatched?

anamorphs – lack spores

A definitive host harbors which stage of a parasite?

adult

Which of the following arthropods does NOT transmit diseases by sucking blood from a human host?

houseflies

A feature that may be found in viruses but never in bacteria is

may contain an RNA genome.

The most conclusive evidence that viruses cause cancers was provided by

cancer that developed in chickens following injection of cell-free filtrates.

Which of the following is NOT utilized to culture viruses?

culture media

What contributes to antigenic shift in influenza viruses?

a segmented genome

The mechanism whereby an enveloped virus leaves a host cell is called

budding.

What is NOT true regarding viruses that infect plants?

They are often cultured in embryonated chicken eggs.

Which of the following is necessary for replication of a prion?

PrPSc

When monocytes leave circulating blood and enter body tissues, they mature into:

Macrophages

In the classical pathway of complement activation, C2a binds:

C4b

Opsonization of ____ enhances phagocytosis; membrane attack Complex is made up of ____.

C3b; made up of C5b, C6, C7, C8, and C9.

List the effects of IFN gamma

All of the Above

List the steps in order of phagocytosis

  1. Chemotaxis and adherence
  2. Ingestion
  3. Phagosome formation
  4. Phagolysosome formation
  5. Digestion
  6. Residual body formation
  7. Discharge

What portion of the T cells can recognize an antigenic peptide?

T-cell receptors (TCRs)

When an antibody binds attachment points of a toxin, bacteria or virus is called:

Neutralization

Type of T cell that stimulates production of eosinophils, IgM and IgE

T-helper 2 (TH2) cell

A recent survivor of Ebola virus donates their plasma (containing antibodies) to a current family member and patient with Ebola. This hopefully results in which type of immunity for the current patient?

artificially acquired passive immunity.

Which are components of an antibody?

All of the Above

Following is a list of fungi, their methods of entry into the body, and sites of infections they cause. Categorize each type of mycosis as cutaneous, opportunistic, subcutaneous, superficial, or systemic.

Blastomyces = Systemic Sporothrix = Subcutaneous Microsporum = Cutaneous Trichosporon = Superficial

A mixed culture of Escherichia coli and Penicillium chrysogenum is inoculated onto the following culture media. On which medium would you expect each to grow?

0.5% peptone in tap water = E. coli 10% glucose in tap water = P. chrysogenum

=

Briefly discuss the importance of lichens in nature.

lichens are responsible for the chemical weathering of large inorganic particles and the consequent accumulation of soil.

Briefly discuss the importance of algae in nature.

Algae are primary producers in aquatic food chains and are important oxygen-producers.

Why is it significant that Trichomonas does not have a cyst stage?

Trichomonas cannot survive for long outside a host because it does not form a protective cyst.

By what means are helminthic parasites transmitted to humans?

Ingestion

Most roundworms are dioecious. What does this term mean

The male reproductive organs are in one individual, and the female reproductive organs in another.

How many phyla are represented in the following list of organisms: Echinococcus, Cyclospora, Aspergillus, Taenia, Toxoplasma, Trichinella?

4

Put the above stages in order of development, beginning with the egg.

  1. metacercaria
  2. redia
  3. adult
  4. miracidium 5.cercaria

4, 2, 5, 1, 3

If a snail is the first intermediate host of a parasite with these stages, which stage would be found in the snail?

  1. metacercaria
  2. redia
  3. adult
  4. miracidium 5.cercaria

2

Fleas are the intermediate host for Dipylidium caninum tapeworm, and dogs are the definitive host. Which stage of the parasite could be found in the flea?

cysticercus larva

Which of the following statements about yeasts are true?

  1. Yeasts are fungi.
  2. Yeasts can form pseudohyphae.
  3. Yeasts reproduce asexually by budding.
  4. Yeasts are facultatively anaerobic.
  5. All yeasts are pathogenic.
  6. All yeasts are dimorphic.

1, 2, 3, 4

Which of the following events follows cell fusion in an ascomycete?

ascospore formation

The definitive host for Plasmodium vivax

Anopheles.

These are obligate intracellular parasites that lack mitochondria.

Microsporidia

These are nonmotile parasites with special organelles for penetrating host tissue.

Apicomplexa

These photosynthetic organisms can cause paralytic shellfish poisoning.

dinoflagellates

Why are freshwater fish more likely to be a source of tapeworm infection than marine fish?

tapeworms better survive in a freshwater environment than a saltwater environment.

Why do we classify viruses as obligatory intracellular parasites?

Viruses absolutely require living host cells to multiply.

List the four properties that define a virus.

contains DNA or RNA;has a protein coat surrounding the nucleic acid;multiplies inside a living cell using the synthetic machinery of the cell;causes the synthesis of virions.

What is a virion?

a fully developed virus particle that transfers the viral nucleic acid to another cell and initiates multiplication.

Compare biosynthesis of a + stranded RNA and a − stranded RNA virus.

Both produce double-stranded RNA, with the - strand being the template for more + strands. + strands act as mRNA in both virus groups.

Some antibiotics activate phage genes. MRSA releasing Panton-Valentine leukocidin causes a life-threatening disease. Why can this happen following antibiotic treatment?

Antibiotic treatment of S. aureus can activate phage genes that encode P-V leukocidin.

Koch’s postulates are used to determine the etiology of a disease. Why is it difficult to determine the etiology of a viral infection, such as influenza?

Viruses cannot easily be observed in host tissues. Viruses cannot easily be cultured in order to be inoculated into a new host. Additionally, viruses are specific for their hosts and cells, making it difficult to substitute a laboratory animal for the third step of Koch’s postulates.

Koch’s postulates are used to determine the etiology of a disease. Why is it difficult to determine the etiology of cancer?

Some viruses can infect cells without inducing cancer. Cancer may not develop until long after infection. Cancers do not seem to be contagious.

Persistent viral infections such as (a) ___________ might be caused by (b) ___________ that are (c ) ___________.

subacute sclerosing panencephalitis = a common viruses = b latent, in an abnormal tissue. = c

Plant viruses can’t penetrate intact plant cells because (a) ___________; therefore, they enter cells by (b) ___________. Plant viruses can be cultured in (c) ___________.

of the rigid cell walls = a vectors such as sap-sucking insects = b plant protoplasts and insect cell cultures = c

Discuss the arguments for and against the classification of viruses as living organisms.

They can be considered living because they contain DNA and/or RNA. However, they can be considered nonliving because they require a host organism to activate biochemical processes.

Why was the discovery of simian AIDS and feline AIDS important?

Simians and felines are ideal models for testing the pathogenicity of SIV and FIV mutants, and possibly provide some insight into HIV and the evolution of retroviruses as well.

Place the following in the most likely order for biosynthesis of a bacteriophage: (1) phage lysozyme; (2) mRNA; (3) DNA; (4) viral proteins; (5) DNA polymerase.

2, 5, 3, 4, 1

The molecule serving as mRNA can be incorporated in the newly synthesized virus capsids of all of the following except

  • strand RNA rhabdoviruses.

A virus with RNA-dependent RNA polymerase

synthesizes double-stranded RNA from an RNA template.

Which of the following would be the first step in the biosynthesis of a virus with reverse transcriptase?

A complementary strand of RNA must be synthesized.

An example of lysogeny in animals could be

latent viral infections.

The ability of a virus to infect an organism is regulated by

all of the above

Which of the following statements is false?

Viruses multiply inside living cells using viral mRNA, tRNA, and ribosomes.

Place the following in the order in which they are found in a host cell: (1) capsid proteins; (2) infective phage particles; (3) phage nucleic acid.

3, 1, 2

Which of the following does not initiate DNA synthesis?

a single-stranded RNA virus (Togaviridae)

A viral species is not defined on the basis of the disease symptoms it causes. The best example of this is

hepatitis.

Cancer patients undergoing chemotherapy are normally more susceptible to infections. However, a patient receiving an antitumor drug that affects eukaryotic cytoskeletons was resistant to Salmonella. Provide a possible mechanism for the resistance.

Salmonella affects host cells by disrupting the plasma membrane with invasins; it then uses the host's cytoskeleton to cause further damage in the cell; the drug could disrupt one of these processes, or it could simply inhibit the division of salmonella cells

The ability of a microorganism to produce a disease is called pathogenicity. The degree of pathogenicity is virulence.

How are capsules and cell wall components related to pathogenicity?

Encapsulated bacteria can resist phagocytosis and continue growing.

Explain how drugs that bind each of the following would affect pathogenicity: iron in the host’s blood

Would inhibit bacteria.

Explain how drugs that bind each of the following would affect pathogenicity: Neisseria gonorrhoeae fimbriae

Would prevent adherence of N. gonorrhoeae.

Explain how drugs that bind each of the following would affect pathogenicity: Streptococcus pyogenes M protein

S. pyogenes would not be able to attach to host cells and would be more susceptible to phagocytosis.

How can viruses and protozoa avoid being killed by the host’s immune response?

All of the Above

The removal of plasmids reduces virulence in which of the following organisms?

Streptococcus mutans

What is the LD50 for the bacterial toxin tested in the example below?

c

Which of the following is not a portal of entry for pathogens?

blood

All of the following can occur during bacterial infection. Which would prevent all of the others?

vaccination against fimbriae

The ID50 for Campylobacter sp. is 500 cells; the ID50 for Cryptosporidium sp. is 100 cells. Which of the following statements is false?

Cryptosporidium is more virulent than Campylobacter.

An encapsulated bacterium can be virulent because the capsule

resists phagocytosis.

A drug that binds to mannose on human cells would prevent

the attachment of pathogenic E. coli.

The earliest smallpox vaccines were infected tissue rubbed into the skin of a healthy person. The recipient of such a vaccine usually developed a mild case of smallpox, recovered, and was immune thereafter. What is the most likely reason this vaccine did not kill more people?

Skin is the wrong portal of entry for smallpox.

Which of the following does not represent the same mechanism for avoiding host defenses as the others?

Surface protein genes in Neisseria gonorrhoeae mutate frequently.

Which of the following statements is true?

A successful pathogen doesn’t kill its host before it is transmitted.

Identify at least one physical factor and one chemical factor that prevent microbes from entering the body through each of the following: urinary tract

Physical: movement out; Chemical: lysozome; acids

Identify at least one physical factor and one chemical factor that prevent microbes from entering the body through each of the following:reproductive tract

Physical: movement out; Chemical: acidic environment in female

Define inflammation, and list its characteristics.

All of the Above

What are interferons?

Interferons are defensive proteins.

Patients with X-linked chronic granulomatous disease are susceptible to infections because their neutrophils don’t generate an oxidative burst. What is the relation of the oxidative burst to infection?

Toxic oxygen products can kill pathogens.

Why does hemolysis of red blood cells occur when a person receives a transfusion of the wrong type of blood?

None of the Above

Give examples of how microbes evade the complement system.

All of the Above

Are the following involved in innate or in adaptive immunity? Identify the role of each in immunity:

TLRs = Innate. Facilitate adherence of phagocyte and pathogen. transferrins = Innate. Bind iron. antimicrobial peptides = Innate. Kill or inhibit bacteria.

What role does transferrin play in fighting an infection?

They transport and store iron

Leukocyte adherence deficiency (LAD) is an inherited disease resulting in the inability of neutrophils to recognize C3b-bound microorganisms. What are the most likely consequences of LAD?

LAD leukocytes can't recognize opsonized Microorganisms, which delays the elimination of the microorganism by innate response and increases the susceptibility to infection

The neutrophils of individuals with Chédiak-Higashi syndrome (CHS) have fewer than normal chemotactic receptors and lysosomes that spontaneously rupture. What are the consequences of CHS?

All of the Above

Legionella uses C3b receptors to enter monocytes. This...

prevents phagocytosis.

Chlamydia can prevent the formation of phagolysosomes and therefore can

avoid being digested.

If the following are placed in the order of occurrence, which would be the third step?

formation of a phagosome

If the following are placed in the order of occurrence, which would be the third step?

activation of C3

A human host can prevent a pathogen from getting enough iron by all of the following except

binding iron with siderophores.

A decrease in the production of C3 would result in

increased susceptibility to infection.

In 1884, Elie Metchnikoff observed cells collected around a splinter inserted in a sea star embryo. This was the discovery of

phagocytosis.

Helicobacter pylori uses the enzyme urease to counteract a chemical defense in the human organ in which it lives. This chemical defense is

hydrochloric acid.

Which of the following statements about IFN-α is false?

It is virus-specific.

Which of the following does not stimulate phagocytes?

histamine

What does MHC stand for?

The major histocompatability complex

What is the function of MHC?

self-antigens

What types of T cells interact with MHC class I? With MHC class II?

CTL cells react with MHC I and TH cells react with MHC II.

Explain a function for the following types of cells: CTL, TH, and Treg.

CTLs destroy target cells on contact. TH cells interact with an antigen to “present” it to a B cell for antibody formation. TR cells suppress the immune response.

What is a cytokine?

Cytokines are chemicals released by cells that initiate a response by other cells.

How would each of the following prevent infection? antibodies against Neisseria gonorrhoeae fimbriae

prevent attachment of the pathogen by interfere with the attachment site on the pathogen

prevent attachment of the pathogen; (a) interfere with the attachment site on the pathogen antibodies against host cell mannose

prevent attachment of the pathogen by interfere with the pathogen’s receptor site.

How can a human make over 10 billion different antibodies with only 25,000 different genes?

Rearrangement of the V region genes during embryonic development produces B cells with different antibody genes.

Explain why a person who recovers from a disease can attend others with the disease without fear of contracting it.

The person recovered because he or she produced antibodies against the pathogen. The memory response will continue to protect the person against that pathogen.

The type of protection provided by the injection of diphtheria toxoid.

artificially acquired active immunity

The type of protection provided by the injection of antirabies serum.

artificially acquired passive immunity

The type of protection resulting from recovery from an infection.

naturally acquired active immunity

A newborn’s immunity to yellow fever.

naturally acquired passive immunity

Antibodies that protect the fetus and newborn.

IgG

The first antibodies synthesized; especially effective against microorganisms.

IgM

Antibodies that are bound to mast cells and involved in allergic reactions.

IgE

Put the following in the correct sequence to elicit an antibody response: (1) TH cell recognizes B cell; (2) APC contacts antigen; (3) antigen fragment goes to surface of APC; (4) TH recognizes antigen digest and MHC; (5) B cell proliferates.

2, 3, 4, 1, 5

A kidney-transplant patient experienced a cytotoxic rejection of his new kidney. Place the following in order for that rejection: (1) apoptosis occurs; (2) CD8+ T cell becomes CTL; (3) granzymes released; (4) MHC class I activates CD8+ T cell; (5) perforin released.

4, 2, 5, 3, 1

Patients with Chédiak-Higashi syndrome suffer from various types of cancer. These patients are most likely lacking which of the following?

NK cells

Where are heterocysts found?

nitrogen-fixing cyanobacteria

Into which field of microbiology would the following scientists best fit:Studies biodegradation of toxic wastes

Biotechnology and Microbial Ecology

Into which field of microbiology would the following scientists best fit?:Studies the causative agent of Ebola virus disease

Virology

Into which field of microbiology would the following scientists best fit?: Studies the production of human proteins by bacteria

Biotechnology and Microbial Genetics and Microbial Physiology

Into which field of microbiology would the following scientists best fit?: Studies the symptoms of AIDS

Immunology

Into which field of microbiology would the following scientists best fit:Studies biodegradation of pollutants

Microbial ecology

Into which field of microbiology would the following scientists best fit: Develops gene therapy for a disease

Molecular biology

Into which field of microbiology would the following scientists best fit: Studies the fungus Candida albicans

Mycology

which field of microbiology would the following scientists best fit Into: Studies the production of toxin by E. coli

Microbial Physiology

Who discovered penicillin

Fleming

Who first observed cells in plants

Hooke

Who proved that microorganisms can cause disease?

Koch

Who disproved spontaneous generation?

Pasteur

What is saccharomyces?

Yeast sold for making bread, wine and beer

What is baccillius thuringiensis?

Biological insecticide

Which are associated with Gram stains

All of the Above

Study Notes

Microbiology Study Notes

Cell Structure and Function

  • Peptidoglycan cell walls, DNA not contained in a nucleus, and flagella are characteristic of a type of microorganism.
  • Prokaryotic cells lack a nucleus, mitochondria, and membrane-bound organelles.

Microscopy

  • Brightfield microscopy: observes specimens stained with dyes.
  • Fluorescence microscopy: observes specimens emitting light.
  • Scanning electron microscopy: observes surface features of samples.
  • Transmission electron microscopy: observes internal structures of samples.
  • Compound light microscope: used to observe stained samples with high magnification.
  • Total magnification = ocular lens magnification x objective lens magnification.

Staining and Microscopy

  • Gram stain: differentiates between Gram-positive and Gram-negative cells.
  • Acid-fast stain: differentiates between acid-fast and non-acid-fast bacteria.
  • Endospore stain: verifies presence of endospores.
  • Mordant: helps stain bind to cell walls.
  • Counterstain: enhances contrast between structures.
  • Decolorizer: removes excess stain from cells.

Microorganism Characteristics

  • Bacteria: essential for life on Earth, perform essential functions like recycling elements.
  • Cyanobacteria: photosynthetic microorganisms.
  • Fimbriae: protein structures aiding in bacterial adhesion.

Metabolism and Enzymes

  • Oxidative phosphorylation: generates ATP through electron transport chains.
  • Citrate synthase: an enzyme inhibited by ATP.
  • Enzyme inhibition: ATP inhibits citrate synthase, preventing excessive citrate build-up.

Microbial Control and Safety

  • Antimicrobial agents: disrupt plasma membranes, damage DNA, or inhibit enzymes.
  • Disinfectants: destroy or inhibit microorganisms on surfaces.
  • Aseptic techniques: prevent microbial contamination in medical settings.

Recombinant DNA Technology

  • Recombinant DNA: DNA constructed from multiple sources.
  • cDNA: complementary DNA synthesized from mRNA.
  • Restriction enzymes: cut DNA at specific sequences.
  • Bioremediation: microorganisms clean pollutants from the environment.

Disease and Epidemiology

  • Koch's postulates: link microorganisms to disease causation.
  • Germ theory of disease: microorganisms cause many diseases.
  • Emerging infectious diseases: new or increasing diseases due to microorganisms.

Miscellaneous

  • Biogenesis: living organisms arise from other living organisms.
  • Spontaneous generation: discredited theory that life can arise from non-living matter.
  • Lysozyme: enzyme degrading peptidoglycan in bacterial cell walls.

This quiz covers stains that can help determine the size and shape of a colorless bacterium without the need for fixing. Test your knowledge on different staining techniques used in microbiology.

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