Final exam Flashcards
Which of the following refers to the type of interaction between two prokaryotic populations in which one population benefits and the other is not affected?
commensalism
Which of the following statements about Neisseria is false?
They are strictly aerobic.
Spirochetes cause the following diseases except for:
Chlamydia
Match each bacterial genus with the best description of its morphology.
Clostridium gram positive rods
Streptococcus chains or pairs of cocci
Staphylococcus clusters of cocci
The envelope of a virus is derived from the host’s:
membrane structures
What is an example of a chronic infection?
HIV
Match the events that are specific for lytic cycle, lysogenic cycle, or both.
Active synthesis of phage DNA and proteins lytic cycle
Phage attaches to the host cell (attachment) both
New phages released, killing host cell lytic cycle
Phage DNA incorporated into the host genome lysogenic
Phage DNA injected into host cell (penetration) both
New phage particles assembled lytic cycle
Which of the following are signs of an animal cell infected by a virus? Check all that apply.
vacuoles in the cytoplasm
inclusion body in the cytoplasm
changes in cell shape
aa
aa
What is the theoretical maximum number of ATP molecules that are produced by aerobic respiration if glucose is the energy source?
38
Which of the following statements about fermentation is TRUE?
Microbes can be differentiated according to the substrates they are able to or unable to ferment.
During which phase would penicillin, an antibiotic that inhibits cell-wall synthesis, be most effective?
log phase
While ____ is able to detoxify a reactive oxygen species, it also produces one, hydrogen peroxide.
Superoxide dismutase
Bacteria isolated from Lake Natron, where the water pH is close to 10, are which of the following?
alkaliphiles
A soup container was forgotten in the refrigerator and shows contamination. The contaminants are probably which of the following?
Psychrotrophs
Bacteria living in salt marshes are most likely which of the following?
Halotolerant
Cells are always producing proteins from every gene they possess.
False
Which of the following enzymes involved in DNA replication is unique to eukaryotes?
telomerase
What are the three different regions of a gene?
Promoter, coding region, and terminator
Each codon within the genetic code encodes a different amino acid.
False
Which of the following is an example of a frameshift mutation?
deletion of one nucleotide
Malaria is caused by a:
Protozoan
E. coli serotype O157:H7 infection may cause severe life-threatening symptoms such as hemorrhagic colitis. Most of the symptoms arise due to the Shiga like toxin, which has a genetic similarity with Shiga toxin of Shigella dysenteriae. Why do scientists think that the Origin of the Shiga toxin gene is from Shigella species that cause dysentery, a disease with a similar symptom?
Because both genera are evolutionarily related, and the same bacteriophage can transduce pieces of DNA between the species.
What is an example of an activator of a repressor protein?
tryptophan
Which of the following scenarios was created through genetic engineering?
The gene that codes for insulin production was inserted into a bacterium and then the bacterium is used to produce insulin.
Which of the following techniques is used to visualize DNA?
Southern blot
Which of the following is the best definition of gene therapy?
The introduction of a non-mutated and functional gene into a patient’s DNA.
S. aureus skin infections usually happens when skin is broken, causing raised, red bumps localized around the hair follicles. These bumps are usually pus-filled, or purulent.
SSSS mostly affects newborns and babies, in which exotoxins cause blisters and large scale skin peeling.
Impetigo is a highly contagious condition common in children, in which exotoxins cause peeling skin, crusty and flaky scabs around the mouth, face and extremities.
To prevent transmission, a person with an active MRSA infection should:
Keep the lesion covered
Nerve cells form long projections called ________.
axons
Order the following structures from the outside (close to the skull) to the inside (close to the brain).
skull
Dura mater
Arachnoid mater
subarachnoid mater
Pia matter
Brain
Rabies is one of the few diseases that can be treated with both passive and active immunizations. Why is that?
The slow spread of the virus in the peripheral allows time for the patient’s immune system to be activated.
The rabies virus is a(n) enveloped RNA virus. After infection, the virus replicates slowly in the peripheral, and rapidly in the CNS.
Who should be getting the meningitis vaccination? Check all that apply.
young people serving in military
travelers visiting the ‘meningitis belt’
young people living in dorms
16 year old for booster
11-12 year old children
N. meningitidis can only grow on chocolate agar and not on regular nutrient agar. What does this mean about its nutritional requirements? Check all that apply.
It needs additional nutrients for growth
It is fastidious
Which of the following are potential reasons why the prevalence of N. meningitidis infections is high in the ‘meningitis belt’? Check all that apply.
These SSA countries have overcrowding and low standards of living
Citizens in these SSA countries may suffer malnutrition
Citizens in these SSA countries may have low immunocompetence
These SSA countries have dry, dusty climate
What types of microbes live in the intestines?
Diverse species of bacteria, archaea, and fungi, especially Bacteroides and Firmicutes bacteria
The absence of Listeria 16S rRNA detected from the amniotic fluid culture means that the fetus is not infected with Listeria.
True
It is common for Listeria to be antibiotics-resistant.
False
What does the acronym “PPE” stand for?
Personal Protective Equipment
Match the description with each biosafety level.
BSL-1 Microbes are not known to cause disease in healthy hosts and pose minimal risks to workers and the environment.
BSL-2 microbes are typically indigenous and and are associated with diseases of varying severity. They pose moderate risk to workers and the environment.
BSL-3 microbes are indigenous or exotic and cause serious or potentially lethal diseases through respiratory transmission
BSL-4 microbes are dangerous and exotic, posing a high risk of aerosol-transmitted infections, which are frequently fatal without treatment or vaccines. Few labs are at this level
What are the advantages of pasteurizing foods and beverages? Mark all correct answers.
to increase the shelf life of a food or beverage
to kill pathogenic microbes
Which of the following terms is used to describe the time required to kill all of the microbes within a sample at a given temperature?
thermal death time
Which chemical disinfectant works by methylating enzymes and nucleic acids and is known for being toxic and carcinogenic?
formaldehyde
Which of the following peroxygens is widely used as a household disinfectant, is inexpensive, and breaks down into water and oxygen gas?
hydrogen peroxide
A scientist discovers that a soil bacterium he has been studying produces an antimicrobial that kills gram-negative bacteria. She isolates and purifies the antimicrobial compound, then chemically converts a chemical side chain to a hydroxyl group. When she tests the antimicrobial properties of this new version, she finds that this antimicrobial drug can now also kill gram-positive bacteria. The new antimicrobial drug with broad-spectrum activity is considered to be which of the following?
semisynthetic
Which of the following combinations would most likely contribute to the development of a superinfection?
long-term use of broad-spectrum antimicrobials
Which of the following does not bind to the 50S ribosomal subunit?
tetracyclines
One of the choices below is true for all of the following: penicillins, cephalosporins, monobactam, and carbapenems.
Is the presence of Beta lactam ring
Which of the following is not an appropriate target for antifungal drugs?
cholesterol
Which of the following is an appropriate target for antifungal drugs?
(1→3) glucan
ergosterol
chitin
Which of the following is a target for an antifungal drug? Check all that apply.
Cell membrane
Chitin synthesis
Ergosterol synthesis
Mitochondria (ETC)
MRSA (Methicillin Resistant Staphylococcus Aureus), develops resistance to Methicillin (low affinity PBP) through this process.
Target modification
Which of the following types of drug-resistant bacteria do not typically persist in individuals as a member of their intestinal microbiota?
MRSA
What are some factors that determine the size of a zone of inhibition in Kirby-Bauer disk diffusion test? Check all that apply.
drug solubility
the nature of the bacteria
the thickness of the agar medium
What is an example of a chronic disease?
Hepatitis B
Which of the following would be a sign of an infection?
fever
What are Koch’s postulates used for?
To determine the cause of a new disease
Pathogen A has an ID50 of 50 particles, pathogen B has an ID50 of 1,000 particles, and pathogen C has an ID50 of 1 × 106 particles. Which pathogen is most virulent?
pathogen A
What is the excessive number of bacterial toxins in the blood known as?
toxemia
What is excessive activation of the immune system and severe response that can lead to life threatening fever, inflammation, and shock, are caused by?
Superantigens
Match the concept with its correct definition:
Sporadic diseases that are seen only occasionally, and usually without geographic concentration
Epidemic diseases for which a larger than expected number of cases occur in a short time within a geographical region
Endemic diseases that are constantly present (often at a low level) in a population within a geographical region
Pandemic and epidemic that occurs on a world wide scale
The way that COVID-19 is spreading is called:
propagated spread
A disease that has a steady frequency over time in a particular geographic location is
endemic
A blanket from a child with chickenpox is likely to be contaminated with the virus that causes chickenpox (Varicella-zoster virus). What is the blanket called?
Fomite
When hiking in Northern California around the Russian River, Mary was bitten by a tick. The tick transmitted the bacteria Borrelia burgdorferi to Mary’s leg tissues while it was obtaining a blood meal. This bacteria is found in certain species of hard-bodied ticks around the USA such as the Deer Tick. The Borrelia bacteria completes part of its life cycle in the ticks.
Because the bacteria completes part of its life cycle in the tick, the tick is considered a _______ for the bacteria.
Biological vector
Why are emerging diseases with very few cases the focus of intense scrutiny?
They are increasing and therefore not controlled
Match the Lyme disease symptom to the stage of the disease.
Bull’s eye (erythema migrans) early localized stage
Facial paralysis early disseminated stage
Meningitis late stage
Which of the following is true of Borrelia burgdorferi (Lyme disease)? Check all that apply.
it has internal flagella
It is gram-negative
It is a spirochete
Which of the following represents a difficulty of diagnosing Lyme disease? Check all that apply.
Many symptoms resemble those of other diseases
Only 70-80% patients develop the bull’s eye rash
Which of the following is not a characteristic of the normal biota of the female reproductive tract during childbearing years?
Vaginal pH is neutral
Match the following virulence factors of K. pneumoniae with their function.
Capsule avoid phagocytosis
LPS cause systemic symptoms such as fever
fimbrial adhesins attachment to host cells
Siderophores sequester iron for survival
Why would a urine culture be informative in diagnosing UTI? Check all that apply.
The lack of growth of bacteria or fungi could indicate a viral infection.
The lack of growth of bacteria or fungi could indicate other conditions such as cancer.
The growth of bacteria would confirm a bacterial caused UTI.
The growth of fungi would confirm a yeast infection.
What is the mortality rate of the 2013 bird flu (H7N9) epidemic?
33%
Which of the following is a component of the influenza virus? Check all that apply.
Neuraminidase (N) spike
M2 ion channel
Capsid proteins
Match the H and N spikes with the steps they are involved in.
Involved in attachment H spike
Involved in release N spike
Cleaves sialic acid receptors to make a clean exit N spike
Binds sialic acid receptor to facilitate entry H spike
Which of the following make up feces? Check all that apply.
Undigested food
Epithelial cells
Mucus
Microbes
The part of the gastrointestinal tract with the largest natural microbiota is the:
Large intestine or colon
Why does the CDC think that the 1 million cases of salmonellosis per year is an underestimate? Check all that apply.
Because most infections are mild and self-limiting
Because many patients do not seek medical help
Which of the following is not a criteria for determining the Biosafety Level of a particular microbe?
whether it is gram positive or gram negative
Match the controlling microbial growth term with the correct definition.
Disinfection reduces or destroys microbial load of an inanimate item through application of heat or antimicrobial chemicals
Sterilization completely eliminated all vegetative cells, endospores, and viruses from an inanimate item
Antisepsis reduces microbial load on skin or tissue through application of an antimicrobial chemical
Degerming reduces microbial load on skin or tissue through gentle or firm scrubbing and use of mild chemicals
When flaming the loop in the lab this is an example of __.
dry-heat sterilization
Which of the following microbial control methods does not actually kill microbes or inhibit their growth but instead removes them physically from samples?
filtration
Soaps are classified as disinfectants.
False
Which of the following best describes the mechanism of action iodophor?
oxidizes cellular material
Bacteriostatic ______________________________________.
Causes a reversible inhibition of growth of the target bacteria
One of the bacteria that is notorious of causing superinfection is:
Clostridium difficile
Which one is the antimicrobic that does not inhibit the cell wall synthesis?
Gentamicin
Which of the following antimicrobials inhibits the activity of DNA gyrase?
Ciprofloxacin
Which of the following is not an appropriate target for antifungal drugs?
cholesterol
There are fewer drugs (Antifungal, antiprotozoan, antihelminthic) available to treat other microbes than bacteria, because____________________________.
They are so similar to human cells that selective toxicity is difficult to achieve
Which of the following resistance mechanisms describes the function of β-lactamase?
drug inactivation
Why have the United States and Europe banned the use of human antibiotics in animal feed?
Because it has been connected to drug resistant problem
What are some reasons why the development of new antibiotics has slowed down? Check all that apply.
developing new drugs is a lengthy process
developing new drugs is expensive
pharmaceutical companies can make more money developing drugs for chronic conditions
What is an example of a chronic disease?
Hepatitis B
During an oral surgery, the surgeon nicked the patient’s gum with a sharp instrument. This allowed Streptococcus, a bacterium normally present in the mouth, to gain access to the blood. As a result, the patient developed bacterial endocarditis (an infection of the heart). Which type of disease is this?
iatrogenic
The number of pathogen cells or particles required to cause active infection in 50% of inoculated animals is _______________________.
Median Infectious Dose (ID50)
Pathogen A has an ID50 of 50 particles, pathogen B has an ID50 of 1,000 particles, and pathogen C has an ID50 of 1 × 106 particles. Which pathogen is most virulent?
pathogen A
Order the following events when superantigen attacks.
1 superantigen stimulates immune cells
2 excess release of cytokines (cytokine storm
3 high fever and low blood pressure
4 multi-organ failure and death
Some of the following are membrane disrupting toxins. Mark all that apply.
Bacterial phospholipases
Leukocidins
Hemolysins
If I said there were 43,103 confirmed cases of the Novel Coronavirus worldwide on February 11, 2020, I would be talking about the ________________ of the disease.
Prevalence
Match each pioneer of epidemiology with his or her contribution.
John Snow determined the source of a cholera outbreak in london
Joseph Lister showed that surgical wound infection rates could be drastically reduced by using carbolic acid to disinfect the surgical tools, bandages, and surgical sites
Florence Nightingale compiled data on the cause of mortality in soldiers, leading to innovations in military medical care
Robert Koch developed a methodology conclusively determining the etiology of a disease
Match the term with its description.
common source spread there is a single source for all the individuals infected
point source spread the common source operates for a short time
continuous common source spread the commons source occurs for and extended time period
intermittent common source spread infection occurs, stop and begins again
Toxoplasmosis is caused by a protozoan parasite called Toxoplasma gondii. This parasite reaches sexual maturity in cats and the intermediate host is usually a rat or a bird. It can cause aberrant behavior in the prey organisms it infects, such as making the scent of cat urine appealing to rodents. Humans can become infected and affected by this eukaryotic single-celled organism, but the organism does not reproduce sexually in human tissues nor is it transmitted to other organisms by humans.
In this scenario, a human would be what to the Toxoplasma gondii organism?
Dead-end host
Toxoplasmosis is caused by a protozoan parasite called Toxoplasma gondii. This parasite reaches sexual maturity in cats and the intermediate host is usually a rat or a bird. It can cause aberrant behavior in the prey organisms it infects, such as making the scent of cat urine appealing to rodents. Humans can become infected and affected by this eukaryotic single-celled organism, but the organism does not reproduce sexually in human tissues nor is it transmitted to other organisms by humans.
In this scenario, a rodent would be what to the Toxoplasma gondii organism?
Intermediate host
Why are emerging diseases with very few cases the focus of intense scrutiny?
They are increasing and therefore not controlled
Which of the following is true of antigenic variation? Check all that apply.
Can evade immune detection
Renders antibodies ineffective
Plays a role in causing chronic disease
Match the tick stage with the host they feed on.
Larvae Mice
Nymphs Mice and humans
Adults deer, occasionally humans
Order the stages of the tick life cycle.
1 eggs
2 larvae
3 nymphs
4 adults
The following are conditions that can establish homeostasis due to the normal microbiota of the vagina. Mark all that apply.
Levels of estrogen
Production of lactic acid
Low pH
It is established shortly after birth
The urinary tract defenses in both males and females consists of mechanical factors such as ________, and chemicals like ________, to prevent the growth of pathogens in the system.
the flushing action of urine; lysozyme
Why would a urine culture be informative in diagnosing UTI? Check all that apply.
The lack of growth of bacteria or fungi could indicate a viral infection.
The growth of fungi would confirm a yeast infection.
The lack of growth of bacteria or fungi could indicate other conditions such as cancer.
The growth of bacteria would confirm a bacterial caused UTI.
What kind of bacterium is Klebsiella pneumoniae? Check all that apply.
Lactose fermenter
Capsule producing
Do you know how to tell the difference between a common cold and the flu?
mild fatigue common cold
severe fatigue flu
nasal congestion rare flu
nasal congestion common common cold
Compare and contrast the 2013 bird flu (H7N9) pandemic and the 1918-1919 flu (H1N1) pandemic.
Capable of person to person transmission 1918-19 pandemic
incapable of person to person transmission 2013 pandemic
Caused by re-assortment of RNA strands from different strains both
Caused by antigenic shift both
Arrange the steps of influenza viral life cycle in the correct order.
1 attachment
2 penetration (endocytosis)
3 uncoating
4 biosynthesis
5 assembly
6 release
Natural defenses of the GI tract include mechanical factors, such as peristalsis, and chemical factors, such as secretory IgA on the surface of the intestines.
True
The normal microbiota provides an additional barrier to infection via a variety of mechanisms. For example, these organisms outcompete potential pathogens for space and nutrients within the intestine. This is known as competitive exclusion. Members of the microbiota may also secrete protein toxins known as bacteriocins that are able to bind to specific receptors on the surface of susceptible bacteria.
Which of the following is used for salmonellosis diagnosis? Check all that apply.
Serological tests such as ELISA
Culture of bacteria
Which biosafety level is appropriate for research with microbes or infectious agents that pose moderate risk to laboratory workers and the community, and are typically indigenous?
BSL-2
Match the temperature with the following treatments.
Freezer -20 °C
Refrigeration 4 °C
Pasteurization 72 °C
Boiling 100 °C
Autoclave 121 °C
Dry oven 171 °C
Which of the following methods when used properly is capable of sterilization?
ionizing radiation