Micro Virus Infecting Wbc Colonztion Infxn Transmission
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- 1.
The synthesis of viral DNA and capsid assembly of Herpesviridae takes place:
- A.
In the cytoplasm right before the final processing.
- B.
In the nucleus with the final processing of the virion followed in the cytoplasm.
- C.
In the nucleus followed by the final processing in the nucleus
- D.
In the cytoplasm with the final processing in the nucleus.
- E.
Only in the nucleus without any subsequent maturation step.
Correct Answer
B. In the nucleus with the final processing of the virion followed in the cytoplasm.Explanation
The correct answer is "In the nucleus with the final processing of the virion followed in the cytoplasm." This means that the synthesis of viral DNA and capsid assembly of Herpesviridae initially occurs in the nucleus, and then the final processing of the virion takes place in the cytoplasm. This suggests that the viral DNA and capsid components are first synthesized in the nucleus, and then transported to the cytoplasm for further processing and assembly into a mature virion.Rate this question:
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- 2.
Identify the virion structure indicated by the arrow:
- A.
The envelope
- B.
The nucleus
- C.
The tegument
- D.
The capsid
- E.
The matrix
Correct Answer
C. The tegumentExplanation
A viral tegument or tegument, more commonly known as a viral matrix, is a cluster of proteins that lines the space between the envelope and nucleocapsid of all herpesviruses. The tegument generally contains proteins that aid in viral DNA replication and evasion of the immune response, typically with inhibition of signalling in the immune system and activation of interferons. The tegument is usually released shortly after infection into the cytoplasm. These proteins are usually formed within the late phase of the viral infectious cycle, after viral genes have been replicated. Much information regarding viral teguments has been gathered from studying Herpes simplex virus.Rate this question:
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- 3.
The replication cycle and the synthesis of gene products of herpesviruses is tightly regulated:
- A.
Viral gene expression is divided into early and late stages. The early gene products activate the expression of the late genes.
- B.
The replication cycle contains only one step: All genes are expressed at the same time
- C.
Viral gene expression is coordinated regulated and sequentially ordered in a cascade fashion. There are three classes of mRNAs.
- D.
Viral gene expression is divided into four stages. Viral gene expression is coordinated regulated and sequentially ordered in a cascade fashion. There are three classes of mRNAs
- E.
Successful replication cycle of herpesviruses is depending on a helper virus with an early and late stage gene expression.
Correct Answer
C. Viral gene expression is coordinated regulated and sequentially ordered in a cascade fashion. There are three classes of mRNAs.Explanation
The correct answer states that viral gene expression in herpesviruses is coordinated, regulated, and sequentially ordered in a cascade fashion, with three classes of mRNAs. This means that the expression of viral genes occurs in a specific order and is tightly controlled. The early gene products activate the expression of the late genes, suggesting a sequential and regulated process. The presence of three classes of mRNAs further supports the idea of coordinated gene expression.Rate this question:
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- 4.
Herpes viruses engage in host-specific and highly subversive, active strategies to circumvent the hosts’ responses. The virus encodes functions that prolong the metabolic activity of the cell until viral replication is completed. Which of the following events interferes with the host’s responses
- A.
Attachment and entry
- B.
Viral gene expression in a cascade fashion
- C.
DNA-dependent RNA polymerase and reverse transcriptase activity
- D.
Apoptosis
- E.
Expression of a fusion protein
- F.
Latency
Correct Answer
D. ApoptosisExplanation
Apoptosis, or programmed cell death, interferes with the host's responses to herpes viruses. When a cell undergoes apoptosis, it self-destructs, preventing the virus from replicating within the cell and spreading to other cells. This is a host defense mechanism to eliminate infected cells and limit the spread of the virus. By inducing apoptosis, the host is able to counteract the virus's strategy of prolonging the metabolic activity of the cell for viral replication.Rate this question:
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- 5.
Nucleoside analogues are pro-drugs that require phosphorylation before becoming effective. Which of the following is the enzyme associated with acyclovir:
- A.
Thymidine kinase
- B.
Valin kinase
- C.
Tyrosine kinase
- D.
Trypsine kinase
- E.
Integrase
Correct Answer
A. Thymidine kinaseExplanation
Thymidine kinase is the enzyme associated with acyclovir. Nucleoside analogues like acyclovir are pro-drugs, meaning they need to be converted into their active form through phosphorylation. Thymidine kinase is responsible for phosphorylating acyclovir, allowing it to inhibit viral DNA replication. Valin kinase, tyrosine kinase, trypsine kinase, and integrase are not involved in the activation of acyclovir.Rate this question:
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- 6.
Which of the following tumors is caused by a virus other than Epstein-Barr virus?
- A.
Posttransplant lymphoma
- B.
Hodgkin’s Disease
- C.
Kaposi’s Sarcoma
- D.
Burkitt’s lymphoma
- E.
Nasopharyngeal carcinoma
Correct Answer
C. Kaposi’s SarcomaExplanation
Kaposi's Sarcoma is caused by a virus other than Epstein-Barr virus. It is caused by a virus called Human Herpesvirus 8 (HHV-8), also known as Kaposi's Sarcoma-associated Herpesvirus (KSHV). This virus is responsible for the development of Kaposi's Sarcoma, a type of cancer that affects the skin and mucous membranes. It is commonly seen in individuals with weakened immune systems, such as those with HIV/AIDS or those who have undergone organ transplantation.Rate this question:
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- 7.
A 26-year old woman visits her physician because of an unusual vaginal discharge. On examination the physician observes a thin, homogeneous, white-gray discharge that adheres to the vaginal wall. The pH of the discharge is 5.5 (normal: < 4.3). Bacterial vaginosis is diagnosed. Which one of the following normal genital flora microorganisms is present in greatly decreased numbers in bacterial vaginosis?
- A.
Corynebacterium species
- B.
Staphylococcus epidermidis
- C.
Prevotella species
- D.
Candida albicans
- E.
Lactobacillus species
Correct Answer
E. Lactobacillus speciesExplanation
In bacterial vaginosis, there is a disruption in the normal vaginal flora, leading to a decrease in the numbers of Lactobacillus species. Lactobacillus species are normally present in the vagina and help maintain a healthy vaginal environment by producing lactic acid, which helps keep the pH low (around 4.3). In bacterial vaginosis, the decrease in Lactobacillus allows for an overgrowth of other bacteria, leading to the characteristic changes in vaginal discharge and increase in pH.Rate this question:
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- 8.
Certain microorganisms are never considered to be members of the normal flora. They are always considered to be pathogens. Which one of the following organisms fits into that category?
- A.
Streptococcus pneumoniae
- B.
Escherichia coli
- C.
Mycobacterium tuberculosis
- D.
Staphylococcus aureus
- E.
Neisseria meningitidis
Correct Answer
C. Mycobacterium tuberculosisExplanation
Mycobacterium tuberculosis is considered to be a pathogen and not a member of the normal flora because it causes tuberculosis, a serious infectious disease that primarily affects the lungs. It is transmitted through the air and can cause severe illness and even death if left untreated. Unlike other organisms listed, such as Streptococcus pneumoniae, Escherichia coli, Staphylococcus aureus, and Neisseria meningitidis, which can be part of the normal flora in certain parts of the body without causing disease, Mycobacterium tuberculosis is always considered a pathogen.Rate this question:
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- 9.
Which one of the following microorganisms is closely associated with dental caries?
- A.
Candida albicans
- B.
Streptococcus mutans
- C.
Prevotella melaninogenica
- D.
Neisseria subflava
- E.
Staphylococcus epidermidis
Correct Answer
B. Streptococcus mutansExplanation
Streptococcus mutans is closely associated with dental caries because it is a type of bacteria that is commonly found in the mouth and is known to contribute to the formation of dental plaque. It metabolizes sugars from the diet and produces acids as a byproduct, which can erode the tooth enamel and lead to the development of cavities. Streptococcus mutans is particularly adept at adhering to the tooth surface and forming biofilms, making it a significant contributor to the initiation and progression of dental caries.Rate this question:
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- 10.
Neither profuse sweating nor washing and bathing can eliminate or significantly modify the normal microbial flora on our skin. Which are the factors that may be important in eliminating nonresident microorganisms from the skin? (Several answers possible)
- A.
Low pH
- B.
Low salt concentration
- C.
Fatty acids in sebaceous secretions
- D.
Absence of enzymes
- E.
Moisture
Correct Answer(s)
A. Low pH
C. Fatty acids in sebaceous secretionsExplanation
The low pH of the skin creates an acidic environment that is unfavorable for the growth of nonresident microorganisms. Fatty acids in sebaceous secretions have antimicrobial properties and can help eliminate nonresident microorganisms from the skin.Rate this question:
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- 11.
The primary effect of lactobacilli in the adult vagina is to
- A.
Maintain an alkaline environment
- B.
Maintain an acidic environment
- C.
Produce a productive mucus layer
- D.
Increase fertility
- E.
Keep the menstrual cycle regular
Correct Answer
B. Maintain an acidic environmentExplanation
Lactobacilli in the adult vagina help to maintain an acidic environment. This is important because the acidic pH inhibits the growth of harmful bacteria and yeast, preventing infections such as bacterial vaginosis and yeast infections. The lactobacilli produce lactic acid, which lowers the pH and creates an unfavorable environment for pathogens. By maintaining an acidic environment, lactobacilli promote vaginal health and protect against infections.Rate this question:
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- 12.
Which of the following is NOT an example of symbiosis?
- A.
Bacteria in the human colon
- B.
Tapeworm in the human intestine
- C.
Protozoa in termites
- D.
Protozoa in the rumen of cattle
- E.
Microbes in a sewage plant
Correct Answer
B. Tapeworm in the human intestineExplanation
Tapeworm in the human intestine is not an example of symbiosis because symbiosis refers to a close and prolonged interaction between two different species where both species benefit. In the case of tapeworms in the human intestine, the tapeworm benefits from the host (human) by obtaining nutrients, but the human is harmed by the presence of the tapeworm. Therefore, it is not a mutualistic relationship and does not fit the definition of symbiosis.Rate this question:
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- 13.
Resident microbiota are found in all of the following locations in the body EXCEPT:
- A.
The lower digestive tract
- B.
The lower respiratory tract
- C.
The upper digestive tract
- D.
The urinary system
- E.
The stomach
Correct Answer
B. The lower respiratory tractExplanation
Resident microbiota refers to the microorganisms that permanently reside in a particular location of the body. The lower digestive tract, upper digestive tract, urinary system, and stomach all have resident microbiota. However, the lower respiratory tract does not have resident microbiota. This is because the respiratory tract is constantly exposed to air and has mechanisms in place to prevent colonization by microorganisms.Rate this question:
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- 14.
Normal microbiota are first acquired during
- A.
During birth
- B.
After one year of age
- C.
By age five
- D.
During the first month
- E.
At age eighteen
Correct Answer
A. During birthExplanation
Normal microbiota refers to the microorganisms that naturally reside in and on our bodies without causing harm. These microorganisms are acquired during birth when the baby passes through the birth canal, where it comes into contact with the mother's microbiota. This is the initial colonization of the baby's body with microorganisms that will become part of its normal microbiota. Therefore, the correct answer is "during birth".Rate this question:
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- 15.
Which of the following is a mechanical vector:
- A.
Housefly
- B.
Cockroach
- C.
Table
- D.
Both A and B are correct
- E.
Both A and C are correct
Correct Answer
D. Both A and B are correctExplanation
Both a housefly and a cockroach are mechanical vectors. Mechanical vectors are organisms that can carry pathogens on their bodies from one place to another, but do not play a role in the life cycle of the pathogen. Houseflies and cockroaches can pick up pathogens on their legs or bodies and transfer them to food, surfaces, or other organisms, potentially spreading diseases. In contrast, a table is not a living organism and therefore cannot act as a vector for pathogens.Rate this question:
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Current Version
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Mar 21, 2023Quiz Edited by
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Jun 06, 2012Quiz Created by
Chachelly
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