bio 208 final
From the data in Table 20.3, which concentration of the antibiotic is the Minimum Inhibitory Concentration (MIC)? Concentration of Antibiotic (μg/ml) Growth in broth 0 + 0.125 μg/ml + 0.25 μg/ml - 0.5 μg/ml - 1.0 μg/ml - 2.0 μg/ml -
0.25
In the 1832 cholera outbreak in New York City 4,000 people were sick with cholera by July 1st and in the month of July another 1,000 people got sick. If the total population of NYC was 250,000, what was the incidence of cholera for the month of July?
1,000/250,000 or 0.4%
What is the thermal death time at 67 degrees C?
15 minutes
At the start of 2015, 36.5 million people were living with HIV in the world. If 2 million people contract HIV in 2015, what was the incidence of HIV in the world in 2015? (Assume the world population at the end of 2015 was 7.5 billion)
2 million/7.5 billion
The doubling time of a bacterium was measured at two different temperatures. Which results would be expected of a thermophile?
220 minutes at 42⁰C; 20 minutes at 62⁰C
Scenario 14.1 During a six-month period, 239 cases of pneumonia occurred in a town of 300 people as a result of Coxiella burnettii infections. Before the outbreak, 2000 sheep were kept 30 miles northwest of the town, 95% of sheep tested were positive for C. burnetii. Wind blew from the northwest, and rainfall was 0.5 cm compared with 7 to 10 cm during each of the previous three years. In situation 14.1 what is the incidence of pneumonia in humans for the six-month period?
239/300 = 77%
In the agar deep tube pictured in Figure 4, when the bacteria are growing at the top of the tube, the cells will produce ___ ATP per molecule of glucose, while the bacteria at the bottom of the tube will produce ___ ATP. Assume the bacteria in this tube cannot use anaerobic respiration.
38, <38
At the start of 2015, 36.5 million people were living with HIV in the world. If 2 million people contract HIV in 2015, what was the prevalence of HIV in the world at the end of 2015? (Assume the world population at the end of 2015 was 7.5 billion)
38.5 million/7.5 billion
A patient with HIV is most contagious when the concentration of viral RNA copies in the blood is highest. Figure 2 shows an example of HIV progression in a patient. Identify the time point when this patient is most contagious.
7 weeks after infection
An experiment is conducted to see how many bacteria remain in a culture at different times and temperatures. The data are shown below in Figure 1. What is the lowest temperature that represents the thermal death point?
77 degrees C
You use a germicide to destroy various types of microbes on surfaces in your house. You have to leave the germicide on the kitchen counter for 1 minute to kill all of the enveloped viruses contaminating it from the chicken you prepared for dinner. If you want to use the same chemical in the bathroom to kill the sporulating Clostridium bacteria in the toilet, you should ____ the incubation time with the same chemical. temperature E. coli remaining after 120 sec 55 1,000 60 800 65 650
>120 seconds
which compound was the LEAST effective against Staphylococcus? disinfectant zone of inhibition A 0 B 2.5 C 10 D 5
A
Which organisms require oxygen for metabolism/energy production?
A - obligate aerobes E - microaerophiles
Which of the following is NOT a characteristic of tuberculosis infection?
A TB diagnosis can be rapidly confirmed because the organism that causes this disease grows quickly.
The figure below shows growth of Serratia marcescens on two petri dishes with (L) and without (R) the production of red pigment based on the temperature at which plates were incubated. Figure 2B shows DNA genomes of two bacteria species, Bacillus cereus and Bacillus anthracis. What is different between the two organisms in A and between the two organisms in B?
A organisms have different phenotype, B organisms have different genotype/phenotype
Which of the following is an example of an opportunistic infection?
After taking an antibiotic you develop thrush, an infection caused by overgrowth of the normal microbe C. albicans in your mouth.
The influenza vaccine is made by combining the most prevalent strains from the previous flu season. Which event would MOST reduce the effectiveness of the new vaccine?
An avian (bird) flu combines with a human flu to make a new hybrid flu strain.
How is a B-cell receptor similar to an antibody?
Antibodies and B-cell receptors can both bind to antigen.
Which of the cells listed below can present extracellular antigens on Class II MHC proteins?
B cells or macrophages
Bacteria were discovered in 1676 but viruses were not discovered until 1892. Why were viruses discovered so much later than bacteria?
Bacteria are larger than viruses.
How does having a capsule increase the virulence of a bacteria cell?
Bacteria with a glycocalyx cannot be phagocytized by immune cells.
After penetration, animal viruses need to be uncoated but bacteriophage need not be. Why?
Bacteriophage inject their DNA into the host during penetration so the capsid doesn't enter the host cell.
Which of the following statements about Neisseria meningitidis is FALSE?
Before starting treatment, it is important to culture a patient sample to confirm that the bacteria is present in the cerebrospinal fluid.
In what two ways can the plague be transmitted?
Biological and droplet
Assuming unlimited resources and space, which line from the graph on the right best depicts a psychrophile grown at 37°C?
C
Which molecule holds the LEAST amount of energy?
CO2
Which of the following is incorrect about temperate phages?
Cause lysis of host cells
Select characteristics of bacteria from the list below.
Cell wall with peptidoglycan Potentially pathogenic Some are germs
What is the reason for antimicrobial resistance being higher in a biofilm than in free-floating cells?
Cells are metabolically inactive in a biofilm.
Which non-specific innate defense mechanism is mismatched with its associated body structure or body fluid?
Complement proteins present in the urine can initiated the destruction of pathogens.
You are in charge of fermentation for Your Favorite Yogurt Company. One day you get a frantic call from your fermentation technologist. It appears that the bacterial cultures in vat one have all lysed due to a bacteriophage infection. You must quickly come up with a solution to keep the yogurt production going.
Create a mutant bacterial strain to use in your fermentation process that has a deletion of the gene encoding the receptor used by the bacteriophage to bind to the bacterium.
Which of the following is NOT a way that the complement system helps to fight infections?
Cytotoxicity causes infected cells to undergo apoptosis.
Which of the following describe a virus outside of a host cell?
DNA or RNA genome inactive
A sensitive bacteria cell is treated with a sulfonamide at time X. Sulfonamides prevent the growth of new bacteria. The graph in Figure 2 shows the effect of sulafonamide treatment on the concentration of ___ over time.
DNA/RNA
Which of the following contribute to the specificity of adaptive immunity?
Each B and T cell has a unique receptor that recognizes antigen.
If the bacteria cell plasma membrane was damaged, what step of metabolism would be affected?
Establishment of the hydrogen ion gradient in the Electron Transport System
You see your lab partner in physics and get a text from them later that night that they have developed the flu. When you get the flu a few days later, your lab partner says you did not catch it from them because in class they were not feeling sick yet. What do you tell your lab partner?
Even if they didn't have signs or symptoms yet, they still could have passed the virus to you during class.
The electron carrier flavin adenine dinucleotide exists in three forms; FAD, FADH, and FADH2. Which form of the electron carrier is the most oxidized?
FAD
Which of the following statements describes the process of horizontal gene transfer?
Gaining a single new gene sequence from outside of the cell.
Yeast is important in the food industry. To take advantage of this fact, Ricky has added yeast to three different types of grapes to try to make wine. Grape 1 has high sugar, Grape 2 has medium sugar, and Grape 3 has low sugar. Predict the outcome of this experiment.
Grape 1 produced the highest level of alcohol, while Grape 3 produced the lowest.
Case study 14 Your patient was admitted to the hospital in New Mexico when his condition worsened. He is severly ill with diarrhea, abdominal pain, vomiting, and low blood pressure. Yesterday, he developed massive bleeding under his skin, and bruises around his swollen lymph node. Diagnostics showed bacteremia and severe sepsis. He was treated with gentamycin, vancomycin, ciprofloxacin, doxycycline, and human activated protein C, but his condition worsened. His blood pressure dropped dramatically, and his kidneys began to fail. He was placed on mechanical ventilation and hemodialysis, and underwent unilateral amputation of one of his hands due to ischemia. What do you think is wrong with your patient?
He has septicemic plague.
Your patient has been on antibiotics for 6 weeks after a case of streptococcal endocarditis, an infection of the inner heart wall. The infection clears up. However, the patient just visited you about a urinary tract infection, and the lab verified that the culprit was E. coli.What do you hypothesize happened in this situation?
Her normal microbiota in the genitourinary tract were killed, allowing E. coli (not killed by the antibiotics) to establish an infection.
Human breast milk contains lactoferrin, lysozyme, secretory IgA, IgG, and complement C3. Identify all of the components that are part of the adaptive immune response.
IgA IgG
In what clinical situation is it most appropriate to use a broad-spectrum antimicrobial?
In a case of bacterial meningitis. The infection spreads so quickly that we must treat it with an antibacterial drug as quickly as possible. We don't have time to determine which drug will work best, because the patient will die in the meantime.
Select all of the TRUE statements about antigen presentation of intracellular and extracellular antigens.
Intracellular antigens are presented on MHC I proteins but extracellular antigens are presented on MHC II proteins. Intracellular antigens are inside a host cell but extracellular antigens are outside and must be brought into the host cell. Cytotoxic T cells recognize intracellular antigens but helper T cells recognize extracellular antigens.
What is the effect of erythromycin on protein production in EUKARYOTIC cells?
It acts only on mitochondrial ribosomes in the eukaryotic cell and has no effect on cytoplasmic ribosomes.
A patient comes into the ER with symptoms of meningitis. Select the true statements from below:
It is important to treat the patient quickly. The patient aquired the menigitis by direct contact. 25% of all cases of menigitis are caused by N. meningitidis
Which of the following is TRUE?
It is possible to be infected with HIV without having AIDS.
Which test is used to determine the susceptibility of a microorganism to an antimicrobial?
Kirby Bauer test
What type of bacteria killed the mouse in this experiment?
Live S strain
Your friend meets you after a long run and is sweating so much that they have soaked through their shirt. What prevents pathogenic microbes from overgrowing in their sweaty armpits?
Lysozyme is a substance in sweat that breaks apart bacterial cell walls.
M. tuberculosis can stay in the extracellular space of the lungs or can reside inside the cytoplasm of a human macrophage cell there. Which of these forms of M. tuberculosis infection would be targeted by CD8+ cytotoxic T cells?
M. tuberculosis inside a macrophage
B cells, macrophages, and dendritic cells differ from other human cells in that they express ______ on their surface
MCH-II receptors
Syphilis is a sexually-transmitted infection caused by the bacteria Treponema pallidum. Syphilis was once treated by infecting the patient with the protozoa that causes malaria, Plasmodium falciparum. Malaria is a disease spread by an insect vector that is characterized by repeated cycles of fever, shaking, and chills. Why would this treatment control syphilis? Select all correct answers.
Malaria will raise the host's body above the optimal growth temperature of T. pallidum. Fever can lead to the production of iron-binding proteins so this essential nutrient is not available to T. pallidum or P. falciparum.
How would you determine the Decimal Reduction Time or D-value of this culture?
Measure the amount of time it takes to reduce the number of bacteria cells in the culture by 90%.
The steps in Pasteur's experiment with the swan-necked flask are shown in the figure below. In step 4, the flask is tilted to allow broth to enter the neck of the flask. Why does this result in microbe growth in the broth in step 5?
Microbes present in the air settle in the neck of the flask and are brought in contact with the broth when the flask is tilted.
Select all of the conclusions that can be drawn from Pasteur's experiments w the S-shaped flasks?
Microbial life can be destroyed by heat. Microbes can be blocked from accessing favorable growth conditions. Microorganisms can be present in nonliving mater, such as air, liquids, and solids.
An electron is removed from pyruvic acid and transferred to NAD+, forming NADH. Which molecule is reduced in this reaction?
NAD+
The reactions of fermentation function to produce _______ molecules for further use in glycolysis.
NAD+
Which of the organisms in the figure has the LONGEST doubling time?
Neisseria meningitidis
Sulfonamides are similar in structure to _______ and work as ________.
PABA competitive inhibitors
Why does antibody concentration fade over time with acquired passive immunotherapy but increase over time with acquired active immunotherapy? Select all that apply.
Passive immunotherapy is direct injection of antibodies that can break down over time. Active immunotherapy is direct injection of antigen so the person's own immune system responds to make antibodies.
Why does milk eventually spoil despite being pasteurized?
Pasteurization reduces the microbe count in the milk and doesn't achieve sterilization.
Why would co-administration of a bacteriostatic drug interfere with the effects of penicillin?
Penicillin interferes with cell wall production/stabilization by cross-linking of peptidoglycan. As such, it only works when the cells are actively replicating and MAKING new peptidoglycan. A bacteriostatic drug works by shutting down replication, holding the cells "static." This would interfere with the mode of action required by the penicillin.
A patient is infected with a bacteria that is producing Beta-lactamase. Which of the following antimicrobial drugs or drug combinations could still have an affect on this bacteria?
Penicillin prescribed along with a Beta-lactamase inhibitor Quinolone
How does a phagocyte "know" it is in contact with a pathogen instead of another body cell?
Phagocytes recognize Pathogen-Associated Molecular Patterns (PAMPs) on the surface of pathogens.
Select the TRUE statements about the bacterial cell wall and membrane drawn below.
Porins are embedded in the cell membrane. LPS is on the surface of the bacteria cell. This cell would stain pink in a Gram stain protocol.
You work at a small family practice. A man in their early fifties comes in with a complaint of intermittent fever and a minor headache. You are the physician that examines them and the only clinical finding is a wound on their thumb that does not appear infected and which they received while skinning a ground squirrel about three days ago. The patient also has several small bug bites, also not appearing infected, around the wrist of the hand with the wound. The lymph nodes at their neck are swollen but inside their throat looks normal and there are no other visible signs of illness. The patient is up to date on their vaccinations and also received the recommended shingles and influenza vaccines earlier this year. The patient has not been in contact with anyone known to be ill with an infection. A patient sample that you requested is sent to the diagnostic lab and subjected to a Gram stain. Although there appears a Gram-negative bacillus bacteria is present in the sample, results are inconclusive because numbers of bacteria were very low. Based on this, what is your immediate action?
Prescribe an antibiotic immediately and also culture the sample.
Which of the following statements describes BOTH aerobic respiration and anaerobic respiration?
Process involves the Electron Transport System and chemiosmosis.
Which of the following regarding antibiotic therapy is FALSE?
Protein synthesis inhibitors are narrow spectrum because only some types of bacteria have a 70S ribosome that is the target of these drugs.
Which of the following is an example of an opportunistic infection?
S. pyogenes present in the mouth of a healthy person spreads to the throat and causes an infection of these tissue and very sore throat in the host.
Use the table below to compare the Ro and CFR values MERS-CoV,SARS-CoV, and SARS-CoV-2. Which statement is TRUE when comparing the 3 coronaviruses? Ro CFR MERS-CoV 0.9 36% SARS-CoV 2.5 9% SARS-CoV-2 3.5 3.5%
SARS-CoV is the most contagious
In an experiment, an animal was injected with two different antigens. After several days, B lymphocytes were removed from the animal and the individual B cells were placed in separate small containers. Then the original two antigens were placed in the containers with each B cell. What results would you expect to observe?
Some B cells produced an antibody to one of the antigens and not both of them. Some of the B cells did not produce antibodies to any of the antigens.
Your neighbor's child has been diagnosed with a disease that causes the child to make no antibodies. Which of the following functions is this child still able to perform at normal levels?
Stop viruses from binding to cells.
Select the best description of competitive inhibition of sulfa drugs on synthesis of folic acid.
Sulfa drugs mimic the shape of PABA and competitively inhibit its binding to the enzyme active site.
Streptococcal infections are extracellular. What adaptive immune cells are important in protecting against strep?
T helper cells B cells
Tamiflu is a common medication given for influenza treatment. It works by blocking sialic acid molecules on the surfaces of host cells to prevent influenza virus from leaving the host cell. Which statement reflects the mechanism of Tamiflu's action?
Tamiflu interferes with the release of the budding viruses from the infected host cells.
Bacteria without a capsule are easier for the host's immune systems to kill than bacteria with a capsule. Why?
The capsule prevents phagocytosis and increases bacterial virulence.
What does an antigen bound to MHC I on the surface of a cell indicate about that cell?
The cell is infected with an endogenous antigen.
How is the lytic cycle different from the lysogenic state with respect to the infected host cell?
The host cell dies during the lytic cycle.
Which of the following statements about noncompetitive inhibition of enzymes is TRUE?
The noncompetitive inhibitor binds to the enzyme and causes the active site to change shape.
An inoculated thioglycolate medium culture tube shows dense growth at the surface and is clear throughout the rest of the tube. What is your conclusion?
The organisms are able to perform aerobic respiration.
During which stages of infection is the patient capable of passing on the infection to others?
The patient can pass on the infection during any of the stages of infection.
Select the statement that describes the period of illness stage in the course of infection and disease.
The patient exhibits strong signs and symptoms of disease and disease is most severe.
Which statement correctly describes the eukaryotic and prokaryotic ribosome?
The ribosome in the eukaryotic cell cytoplasm is larger than the prokaryotic ribosome.
What is happening in the uncoating phase of the SARS-CoC-2 life cycle shown below?
The viral envelope is fusing with the host cell membrane.
A kid named Beau develops a rash on their face around the nose and mouth that is crusty and yellowish. The wound is swabbed and tests show that the microbe infecting the wound is resistant to bacitracin and produces catalase. What can be concluded about the wound? Select all that apply.
The wound is infected with S. aureus. If tested, the microbe would also be positive for coagulase production The wound should be treated with antibiotic cream.
Outbreaks of impetigo have occurred at two local preschools. To determine if the two outbreaks are being caused by the same microbe, cotton swabs are used to take a sample of microbes from the blisters of children at each preschool. Samples are subjected to Gram stain and additional tests. Gram stain results indicate that samples from both preschools are Gram positive coccus bacteria. Based on these results alone, why can't you conclude that the microbe causing the two outbreaks is the same?
There are two possible Gram positive microbes that can cause impetigo.
Which statement about horizontal gene transfer is associated with conjugation?
This mechanism may result in the transfer of genes that encode antibiotic resistance. This mechanism requires direct cell-to-cell contact. This mechanism of genetic transfer always involves a one-way transfer from a donor cell to a recipient cell. This mechanism is initiated by cells with F plasmids.
Why does the electron transport system create a hydrogen ion gradient by chemiosmosis?
To power ATP synthase to produce ATP.
What is the hallmark of all horizontal gene transfers?
Transfer of DNA between organisms of the same generation.
Which of the following violates Koch's postulates?
V. cholera bacteria can be isolated from both cholera patients and healthy individuals.
In 1994 a civil war in Rwanda displaced 3.9 million people, many of whom fled to refugee camps in Goma, Zaire. Conditions in refugee camps led to rapid spread of infectious diseases including a disease causing severe, watery diarrhea. Microbes isolated from the stool samples of these patients with Gram stained showed a curved, Gram negative microorganism to be present. This microbe was identified as Vibrio cholerae. Based on this information and what you know from chapter 3, what can you conclude?
V. cholerae has a two plasma membranes that surround a peirplasmic space and a peptidoglycan cell wall.
How do the cell walls of bacteria and viruses differ?
Viruses don't have cell walls because they are not cellular.
Which of the following statements about viruses is FALSE?
Viruses exclusively use their own enzymes.
Select all of the following that are true reasons why viruses are not living.
Viruses have DNA or RNA but never both. viruses are acellular Viruses are obligate intracellular parasites and cannot reproduce without a host. Viruses lack essential genes and rely on host genes to perform these functions.
In transduction, an error occurs in one of the steps in the phage replication cycle. Which statement correctly explains the error?
When the phage is constructed inside the bacteria cell, bacterial DNA is inserted into the capsid.
A short list of Covid-19 "facts" is being circulated on facebook. Find the statements that are not correct from this "fact" list.
You cannot give another person Covid-19 if you are not experiencing symptoms. Covid-19 is the first coronavirus to infect humans. The genes of the virus that causes Covid-19 are made of DNA.
As a new employee at a hospital, you are required to take the Mantoux skin test. After 48 hours, you return to the employee clinic to have your test read and it is positive. At this point, what can you conclude?
You either have tuberculosis or been exposed to someone who has it
Where is H+ concentration the highest?
a
Which of the following would alter a B cell's ability to bind to an antigen?
a DNA mutation that causes an alteration in the B cell receptor
A superinfection results from
a decrease in most normal biota resulting in the overgrowth of an unaffected species.
What is the correct definition of an endemic disease?
a disease that is constantly present in a population
A clinical microbiologist makes serial dilutions of several antimicrobial drugs in broth and then incubates each drug dilution with a standard amount of a patient's isolated pathogen. What is this microbiologist setting up?
a minimum inhibitory concentration (MIC) test
Which of the following would be a virulence factor of a pathogen?
a surface protein allowing the pathogen to bind to host cells AND release of an exoenzyme that breaks apart red blood cells so they can be used for nutrients by the microbe
Select all of the protective actions of urine.
acidic pH Contains lysozyme which breaks down peptidoglycan Contains lactoferrin, an iron-binding protein Contains secretory IgA
A Healthcare-Association Infection is
acquired during the course of hospitalization
Which of the following would result in a positive tuberculin skin test?
active TB dormant TB Previous exposure to TB Vaccination with BCG
A patient has a lesion on their thigh that is infected with MRSA. MRSA bacteria are coated in a capsule and are able to survive in the cytoplasm of the phagocyte to prevent their destruction by phagocytosis. Which steps in phagocytosis are MRSA able to inhibit?
adherence AND formation of the phagolysosome
Select all of the following that are shared characteristics between pathogenic microbes and normal microbiota.
adherence to host tissues entering the host by a portal of entry activates an immune response
Which of the following forms of metabolism produces the MOST ATP per molecule of glucose?
aerobic respiration
Antibodies are capable of binding up several antigens at once in order to reduce the number of infectious agents that need to be dealt with. This function of antibodies is known as
agglutination
Which of the following regarding antimicrobial control agents is FALSE?
alcohol is most effective at 100% concentration
Bacteria #1 has an ID50 of 50 particles, bacteria #2 has an ID50 of 250 particles, and bateria #3 has an ID50 of 1x106 particles. Which bacteria is pathogenic?
all of them are pathogenic
A major difference between anaerobic respiration and aerobic respiration is that
anaerobic respiration uses an inorganic molecule as a final electron acceptor while aerobic respiration uses oxygen.
Scenario 14.1 During a six-month period, 239 cases of pneumonia occurred in a town of 300 people as a result of Coxiella burnettii infections. Before the outbreak, 2000 sheep were kept 30 miles northwest of the town, 95% of sheep tested were positive for C. burnetii. 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 reservoir of infection in Situation 14.1 was
animals
The antimicrobial compounds naturally produced by some molds and bacteria are generally called
antibiotics
B cells are activated by a(n) _____ to become plasma cells.
antigen
The histocompatibility complex proteins (MHC) function in
antigen presentation recognition of self
Symptoms of disease differ from signs of disease in that symptoms
are changes felt by the patient.
What type of immunity results from vaccination?
artificially acquired immunity
One of the steps in the animal virus replication cycle of SARS-CoV2 is shown below. Which step?
attachment
What type of vaccine is the live, weakened measles virus?
attenuated whole cell vaccine
In the modern phylogenetic tree, identify the three domains in order, A, B and C
bacteria archaea eukarya
Which of the following statements are FALSE?
before surgery, the patients skin must be disinfected
The Valley of the Drums is a site in Bullitt County, KY that is contaminated with a toxic waste called PCB (polychlorinated biphenyl). This site may be a good candidate for microbial
bioremediation
The compound that is used in prepping surgical skin sites is ______.
bisguanides
the blood brain barrier prevents material from the _____ from interacting with the ____ of the central nervous system
blood CSF
You work at a small family practice. A man in their early fifties comes in with a complaint of intermittent fever and a minor headache. You are the physician that examines them and the only clinical finding is a wound on their thumb that does not appear infected and which they received while skinning a ground squirrel about three days ago. The patient also has several small bug bites, also not appearing infected, around the wrist of the hand with the wound. The lymph nodes at their neck are swollen but inside their throat looks normal and there are no other visible signs of illness. The patient is up to date on their vaccinations and also received the recommended shingles and influenza vaccines earlier this year. The patient has not been in contact with anyone known to be ill with an infection. What patient samples would you request immediately for testing?
blood draw
You are peer reviewer for a scientific article about MRSA and the authors have incorrectly written the microbe name as staphylococcus A. How would you correct the error in how the microbe name is written?
capitalize the S in the genus name, change the A in the species to lower case AND write out the full species name
Which of the following structures are present in all animal viruses?
capsid spikes a genome
The energy released during ____ reactions is used to make ____ in human and bacterial cells.
catabolic, ATP
Catabolic _____ reactions release _____ energy that results in production _____ of ATP molecules.
catabolic; release; production
An interaction between two immune cells and an antigen is shown in the figure. MHCI and the T cell receptor are sticking out from the surface of cell 1 and cell 2 respectively and interacting with each other as shown. Identify the immune cells.
cell 1: nucleated cell, cell 2: CD8 T cell
"Rice water stools" are characteristic of
cholera
Escherichia coli is a usually harmless bacteria but can sometimes cause food poisoning when ingested. Which statement about the binomial nomenclature system used to name Escherichia coli is FALSE?
coli is the genus name.
The lower respiratory tract is protected by all of the following EXCEPT
competition with the normal flora of the lungs
A strain of Neisseria gonorrheae that was formerly sensitive to penicillin has recently acquired the ability to produce penicillinase, an enzyme that inactivates penicillin. Evidence indicates that this is not a new mutation but rather a gene received from another bacterium. The gene is now spreading rapidly among the population, causing the recipient bacteria to be resistant to penicillin. Along with penicillinase, the gonnorheae gained the ability to make pili and extend to connect with other bacteria. How did the N. gonnorheae receive these new genes?
conjugation
How could disease transmission be stopped at the portal of exit?
covering the mouth when sneezing wearing a condom
Ultraviolet radiation at the bactericidal wavelength destroy bacteria by
damaging nucleic acid
You're measuring the number of cells in a culture by turbidometry. You measure them at 8am and then again at 10am. The turbidity of the culture is LESS at 10am. In what growth phase is the culture?
death phase
______ is the preservation of beef jerky from microbial growth by removal of water and is a ____ form of microbial control.
desiccation bacteriostatic
Staphylococcus aureus can be passed from one person to another by direct or indirect contact transmission. The microbe sometimes results in infection in the person it is transmitted to and transmission can occur in the hospital or community setting.
direct or indirect contact always hospital or community
Botulinum toxin
disrupts the functioning of muscle cells to prevent contraction
Bacteria may become antibiotic resistant due to
drug inactivating enzymes alteration in the target molecule decreased uptake of the drug increased elimination of the drug
Where is ATP produced?
e
The core of every virus particle always contains ______.
either DNA or RNA
Often the mnemonic device "OIL RIG" is used to remember the principles of redox reactions. Oxidation Is Loss and Reduction Is Gain of what?
electrons
You have recently identified a new toxin. It is produced by a gram-negative bacterium. It is composed mostly of lipids, has a low toxicity, is heat stable, and induces general inflammation and fever. Based on these characteristics, how would you classify this toxin?
endotoxin
lipopolysaccharide
endotoxin produced by gram-negative bacteria that elicits a strong immune response in the host
Most pathogens that gain access through the skin
enter through hair follicles and sweat ducts
Which of the following is not present in all viruses?
envelope
If the normal range for coccidioidomycosis is <200 cases on each continent, how would you categorize the occurrence of this disease in 2015 based on the data below?
epidemic
Which of the following definitions is INCORRECT?
epidemic: a disease that is endemic across the world
Who should be screened for Chlamydia and Gonorrhea?
everyone who is 14-25 years old and sexually active
Hyaluronidase produced by streptococci and staphylococci
exoenzyme produced to degrade connections between host cells
Urease produced by H. pylori
exoenzyme produced to neutralize pH and enable the microbes to penetrate the host tissue
During which phase is generation time measured?
exponential growth phase
Which of the following phases of the bacterial growth curve is matched with the correct definition
exponential growth phase--the phase in which organisms are actively dividing and the generation time is constant
A viruses will have the ability to attach to and enter almost any host cell.
false
Broad-spectrum antibiotics have minimal effect on the normal microbiota.
false
Dry heat takes a much shorter time to sterilize material than wet heat.
false
Most microbial contaminants of food are killed or inactivated at freezing temperatures.
false
T cells are responsible for directly manufacturing antibodies.
false
Your immune system does not change from the time you are born until death.
false
The primary virulence factor of Neisseria gonorrhoeae is ______.
fimbriae
______ is very toxic but is commonly used to disinfect hospital equipment and kills microbes by inactivating their proteins.
formaldehyde
Epstein-Barr virus has been implicated in all of the following except
gastritis
In April 1990, the El Paso County (Colorado) Health Department recognized an outbreak of drug-resistant gonorrhea in Colorado Springs. 56 cases of penicillin-resistant Neisseria gonorrheae occurred from December 1989 through March 1991. To gather information about the outbreak, 410 persons related through a densely connected set of social or sexual associations were interviewed. What can public health workers tell individuals in this network to stop the spread of Gonorrhea in this population?
gonorrhea can spread from an infected mother to fetus
A 30-year-old woman was hospitalized after she experienced convulsions. On examination, she was alert and oriented and complained of a fever, headache, and stiff neck. Which of the following is most likely to provide rapid identification of the cause of her symptoms?
gram stain of cerebrospinal fluid
A cell is unable to replicate its DNA because the double helix will not open into a replication fork. This is probably due to a malfunctioning of which enzyme?
helicase
The H1N1 swine flu was a worldwide pandemic in 2009. It was named for a similar virus found in pigs and for the two main antigens always present in flu viruses. H for ____ antigen that controls attachment to host cells and N for ____ antigen that controls release from host cells.
hemagglutinin, neuraminidase
You add the two bacteria shown in the figure below to the same tube with liquid growth media. After a 24 hour incubation with shaking, you are able to identify B. cereus cells that contain the pX01 and pX02 genes. Which explains how B. cereus most likely acquired pX01 and pX02?
horizontal gene transfer
Typhoid Mary was an asymptomatic carrier of typhi bacteria and spread the bacteria to other hosts by passing it in food she prepared. Mary was a ____________ reservoir of S. typhi and spread typhoid fever by ______ transmission.
human vehicle
Why do antimicrobial drugs like erythromycin that target protein synthesis in bacteria also harm human cells at high doses?
human cells have a 70S ribosome derived from bacteria in their mitochondria
Staphylococcus bacteria produce many enzymes that increase their virulence. Which enzyme is matched with its correct function?
hyaluronidase - breaks connections between host cells and enables the bacteria to spread
Some penicillin-resistant bacteria are capable of making β-lactamase enzymes that can ___ penicillin by breaking the bond labeled ____.
inactivate 3
You grow a bacteria in many oxygen concentrations. The bacterium takes 45 minutes to double if grown in a high oxygen environment. If this bacterium is a facultative anaerobe and you now incubate it in a tube with no oxygen, you would expect the doubling time of the bacteria to:
increase
You use a germicide to destroy various types of microbes on surfaces in your house. You have to leave the germicide on the kitchen counter for 1 minute to kill all of the enveloped viruses contaminating it from the chicken you prepared for dinner. If you want to use the same chemical in the bathroom to kill the sporulating Clostridium bacteria in the toilet, you should ____ the incubation time with the same chemical.
increase
In which of the following patterns of disease does the patient experience no signs or symptoms?
incubation
A disease transmitted by a needlestick is an example of
indirect contact transmission by fomite.
A physician transmits Influenza from one patient to another patient because of viral contamination on the stethoscope. The flu was transmitted _____ via _____.
indirectly fomite
Moist heat kills microorganisms by
irreversible denaturation of proteins
The DNA found in most bacterial cells
is circular in structure.
Dry heat ___
is less efficient than most heat
How would a noncompetitive inhibitor interfere with a reaction involving the enzyme and molecules shown below?
it would bind to B
What is the target of treatments for acne?
kill P. acnes to decrease the number of these bacteria
Important characteristics of antimicrobial drugs include
low toxicity for human tissues high toxicity against microbial cells. a lack of serious side effects in humans. stability and solubility in body tissues and fluids.
Which area of the Gastrointestinal tract habors the largest number of normal microbiota?
lower GI tract
Phagocytes utilize all of the following to help locate and contain microorganisms EXCEPT
lysozyme
A treatment for bacterial infections from the early 20th century has made a comeback; the use of bacterial viruses to eliminate bacterial infections. Which type of virus would be best to use for treating and killing a bacterial infection in humans?
lytic bacteriophage
Helicobacter pylori can grow in the stomach because it
makes urease enzyme that neutralizes HCl
A house fly transmits tularemia by carrying tularensis on its feet. This is an example of
mechanical transmission
Viruses exhibit all the following except ______.
metabolism
The major significance of Robert Koch's work is that
microorganisms cause disease
Chemotaxis is
movement towards or away from a chemical stimulus.
Genetic change in bacteria can be brought about by
mutation conjugation transduction transformation
A researcher creates an antibiotic that binds to only B. anthracis (the causative agent of anthrax), lysing the cell from the outside. After a couple of years using this antibiotic, some resistant organisms are found. Which of the following best outlines the mechanism for the development of this resistance?
mutation of B. anthracis ->altered target -> resistant bacterium
Inhibitors that bind away from the enzyme's active site to prevent substrate binding to the enzyme are
noncompetitive
According to the theory of spontaneous generation, what is the source of life?
nonliving matter
Your child develops an ear infection. The physician gives you ten days' worth of antibiotics. After three days, you stop giving your child the antibiotics. Which of the following is TRUE?
not finishing the antibiotics can select for more antibiotic-resistant bacteria over time
The first step for directly linking a microbe to a specific disease according to Koch's postulates is to
obtain a sample of blood or other bodily fluid from a diseased animal
What is the benefit of complementary base pairing in the DNA molecule?
one strand can serve as a template for construction of a second strand during DNA replication
There were five major cholera outbreaks in the 1800's that occurred all over the world and killed nearly 40 million people. During this time period, cholera can be classified as a(n) _____ disease.
pandemic
Endotoxins are
part of the gram-negative cell envelope
Disinfection of beverages such as apple juice, milk, and wine is optimally achieved by ______.
pasteurization
Which of the following is NOT a sterilization method?
pasteurization
All _____ have a beta-lactam ring.
penicillins
Cells were exposed to varying concentrations of an antibiotic. Which of the following mechanisms of action of this antibiotic could be supported by the data below? Inhibition of
peptidoglycan linkage
A child falls and suffers a deep cut on her leg. The cut went through her skin and she is bleeding. Which of the following defense mechanisms will try to eliminating contaminating microbes immediately?
phagocytosis and the inflammatory response
The digestive tract is essentially one long tube. The order of the structures, beginning with the mouth, is
pharynx, esophagus, stomach, small intestine, large intestine.
Which of the following statements about pili is NOT true?
pili are used during cell division.
Helicobacter pylori can grow in the stomach because it
possesses an enzyme that neutralizes HCl
A virus's ability to infect an host cell depends primarily upon the
presence of receptor sites on the host cell membrane.
Which of the following modes of action would be the most selectively toxic when treating a bacterial infection in a human?
preventing cell wall synthesis
Lysozyme would be as a useful host defense in which of the following cases?
preventing entry of a pathogenic bacteria into the upper respiratory tract
You have isolated a mutant strain of Serratia marscesens that has an abnormal ribosome that is not functioning well. Which of the following might be affected by this change?
production of proteins
Shelley is suffering from a very sore throat. Analysis of a swab from her throat confirmed that the causative organism is Streptococcus pyogenes, a gram-positive bacteria. Imagine that you are the technician looking at the Gram stain from Shelly's culture. What would you expect to see as you look through the microscope?
purple, spherical-shaped organisms arranged in chainlike formations
The circulating substances that affect the hypothalamus and initiate fever are ______.
pyrogens
Which list of three terms best describes innate immunity?
quick non specific unchanged from birth
In order to prepare instruments for surgery, it is necessary to sterilize them which is
removal of all microbial life
The multidrug resistant efflux pumps in many bacterial cell membranes function by
removing the drug from the cell when it enters
Cases of whooping cough, caused by Bordetella pertussis infection, are increasing in Kentucky. Previously successful treatment with erythromycin is now failing. What structure in pertussis is most likely affected by a mutation that is making the organism more resistant to this antibiotic?
ribosome
Which of the following represents the use of osmotic pressure as a microbial control method?
salting of meat
You need to measure microbial growth in a culture of motile bacteria. The concentration of the culture is very low, you need to determine the number of live bacteria cells, and you have plenty of time. Which method would be the best to use?
serial dilutions and plate counts
Antigenic ____ is the result of reassortment of gene responsible for the production of influenza virus spike proteins between different virus particles while in the same host, whereas antigenic ____ is the result of point mutations in the spike proteins.
shift, drift
If pathogen A is more resistant to an erythromycin disc on a Kirby-Bauer plate compared to pathogen B, then pathogen A will have a/n _____ zone of inhibition compared to pathogen B.
smaller
Which of the following is the best definition of epitope?
specific regions on antigens that interact with antibodies
You are a dairy farmer and need to determine if a batch of milk contains any live E. coli. Because you have to ship the batch of milk out in 6 hours, you need to know the results quickly. You have to consider that E. coli is a motile bacteria but do not need to distinguish live from dead cells. Assume you have all the necessary equipment for any method of quantifying microorganisms, which would you use for your purposes?
spectrophometer
Which virulence factor causes MRSA wounds to be filled with a lot of pus?
stapholysins
Refer to the table. Bacteria culture A is most likely in the _____ growth phase and bacteria culture B is most likely in the ____ growth phase. # cells @ time 1 # cells @ time 2 bacterial culture A 152 150 bacterial culture B 526 36
stationary death
The removal of all life forms from inanimate objects is termed ______.
sterilization
What is the morphology and arrangement of the bacteria shown below?
streptobacillus
Sporulating bacteria are able to
survive harsh conditions like high heat, dehydration and low nutrient levels.
A characteristic symptom of plague is
swollen lymph nodes
The most selectively toxic drugs are those that
target microbial sites that are not present in humans
Alexander Fleming had been running tests using Staphylococcus, and he left some plates out to incubate. Evidently, after returning to his lab after the weekend, he found that Penicillium mold was growing on his agar plates containing the growth of Staphylococcus. Looking more closely, he found a large, clear area around the mold colony where Staphylococcus colonies did not grow. Given this situation, a valid hypothesis would be that
the Staphylococcus was being inhibited by the Penicillium mold.
Use of antibiotics in animal feed leads to antibiotic-resistant bacteria because
the antibiotics kill susceptible bacteria, but the few that are naturally resistant live and reproduce, and their progeny repopulate the host animal.
The log-scale plot of bacterial growth is straight up during the exponential growth phase. What does this tell you?
the bacterial growth rate is constant
the zone of inhibition is a measure of
the diameter of the area where E. coli growth is prevented
Selective toxicity exhibited by a drug means that
the drug is effective against the target organism, but not the human host
How would a limited food supply affect the bacterial growth curve?
the log phase would be shortened
Which of the following statements about salmonellosis is FALSE?
the mortality rate is high
Human-to-human transmission of plague is usually by
the respiratory route
Figure 1 shows the antibody response in a host following antigen exposure. Based on the figure, you can conclude that the antigen in the initial exposure and in the secondary exposure was _____.
the same antigen
The lysogenic cycle and the lytic cycle of bacteriophage are depicted in Figures 6.7 and 6.8 in your book (https://openstax.org/details/books/microbiology (Links to an external site.)) and in our lecture slides for Chapter 6. Which of the following ONLY happens during the lysogenic cycle (NOT during the lytic cycle)?
the viral DNA is integrated into the host cell genome
A sample of E. coli has been subjected to heat for 17 minutes and all of the cells in the sample are destroyed. Which of the following terms best describes this event?
thermal death time
The difference between thermal death time and thermal death point in microbiocidal activity is that
thermal death time is the shortest amount of time required to kill an organism at a specific temperature, . whereas thermal death temperature is the lowest temperature required to kill an organism in 10 minutes
Which of the following pairs of microbe classification terms and optimal growth temperatures is mismatched?
thermophile, 25°C
Which of the following is NOT a reservoir of infection?
these are all reservoirs of infection: a sick person a healthy person a river a chicken
An ideal antimicrobial therapeutic drug exhibits all of the following characteristics, except
they are easily broken down by host
What is the purpose of NADH and FADH2 in aerobic respiration?
they carry electrons to the electron transport system
Why would breaking the flask at 'a' most likely lead to contamination of the broth?
this allows for cell contaminants in the air to easily reach the broth
What is the overall goal of metabolism?
to make ATP
A Pseudomonas strain carrying a plasmid-containing gene for toluene degradation was applied to toluene-contaminated soils. Two months later, Molly Microbiologist isolated Bukholderia that could degrade toluene. She analyzed the genes involved and found that they were located on a plasmid and were identical to those in the Pseudomonas. The most likely explanation is
transduction
The function of the "ciliary escalator" is to
trap microorganisms in mucus and move them away from the lower respiratory tract.
A student has obtained a sample of pond water for study. Using the high-power lens, he observes several cells with nuclei. He can conclude that the cells are NOT bacteria.
true
An asymptomatic, healthy carrier of a disease is a living reservoir of infection.
true
Chlamydia and gonorrhea are most prevalent in individuals younger than 25 years of age.
true
Chlamydia is the most common reportable sexually-transmitted infection (STI) in the United States.
true
Glycolysis is utilized by cells in both respiration and fermentation.
true
In a patient infected with HIV, the number of CD4 T cells decreases as the amount of viral RNA increases.
true
In hospital patients, normal microbiota can become opportunistic pathogens that lead to Healthcare-Associated Infections.
true
Methicillin-resistant Staphylococcus aureus (MRSA) is harmless on healthy, intact skin but can cause infection if introduced to other parts of the body.
true
Moist heat destroys organisms by denaturing proteins.
true
Recombination will always alter a cell's genetic material
true
The MIC is the smallest concentration of an antimicrobial required to inhibit the growth of the microbe.
true
Viruses are unable to reproduce outside of a host cell.
true
Select characteristics of FUNGI from the list below.
uni or multicellular eukaryotic
Chlamydia and gonorrhea can infect the ___ of men and women.
urethra
Cholera is a disease that can spread when sewage mixes with drinking water. Cholera is spread by ____ transmission.
vehicle
Scenario 14.1 During a six-month period, 239 cases of pneumonia occurred in a town of 300 people as a result of Coxiella burnettii infections. Before the outbreak, 2000 sheep were kept 30 miles northwest of the town, 95% of sheep tested were positive for C. burnetii. 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 method of transmission of the disease in Situation 14.1 was
vehicle
Genes can be shared between organisms by horizontal or vertical gene transfer. Humans are capable of _______ gene transfer and bacteria are capable of ________ gene transfer.
vertical, both horizontal and vertical
The macrolides (arythromycin, azithromycin, carithomycin, dirithromycin, etc.) are antibiotics that bind to the large subunit of the bacterial ribosome. These antibiotics do not work on viruses because:
viruses do not have ribosomes