46 Questions
Which of the following is a common disease caused by viruses?
COVID-19
What type of staining techniques are used for different infectious agents?
Gram staining
Which infectious agent is only visible with an electron microscope?
Viruses
What is a notable example of a protozoan that causes a common disease in humans?
Malaria
Which infectious agent is generally visible under a light microscope?
Bacteria
What are the five types of infectious agents (microbes) that can affect any tissue in the body?
Bacteria, protozoa, fungi, helminths, viruses
In the context of Reverse Transcription PCR (RT-PCR), which of the following statements accurately describes the process and its distinctive features?
RT-PCR is designed for the amplification of RNA, initiating with a reverse transcription step, followed by denaturation, annealing, and elongation.
What is the gold standard for the diagnosis of infections?
Culture
Which microorganisms are thought to have a role in resistance to pathogens, maintaining the intestinal epithelium, and controlling immune function?
Bacteria
What is the main function of ELISA (Enzyme-linked immunosorbent assay)?
Identifying antigens
What is the primary characteristic of pathogenic bacteria?
They can cause disease
In the context of histochemical staining for microorganism detection, why is histochemical staining not the preferred method for identifying microbes?
Histochemical staining lacks specificity in microbial identification.
How do pathogenic bacteria cause damage in the body?
By killing cells and releasing toxins
What is the function of serologic identification in diagnosing infections?
Detects and measures levels of antibodies in blood samples
What is the role of gut microbiome in humans?
Metabolizing dietary and pharmaceutical compounds
What is the primary characteristic of bacteria in the gut microbiome?
They can be harmful or beneficial
What is the primary characteristic of most bacteria in the body?
They are neutral
What are the stages involved in viral pathogenesis?
Entry, local replication, dissemination, shedding, and onward transmission
What is the structure of viruses?
Small genetic code collections surrounded by a protein coat
How does SARS-CoV-2 enter human cells?
Through the fusion of the virus membrane with the human cell membrane
What is the mechanism of viral entry for SARS-CoV-2?
Fusion of the virus membrane with the human cell membrane
What is the genetic makeup of SARS-CoV-2?
Single-stranded RNA virus
What is the role of Polymerase Chain Reaction (PCR) in diagnosis and monitoring of diseases?
Used for detection of microorganisms
What is the function of Reverse Transcription PCR?
Targets RNA and is used for diagnosis and monitoring of diseases
What are the characteristics of viruses in causing disease?
Can cause local or systemic disease, destroy host cells, and induce cell death or immunosuppression
What are the characteristics of Long COVID?
Occurs due to the pathophysiological processes associated with COVID-19
What are the consequences of viral pathogenesis?
Destruction of host cells and induction of cell death or immunosuppression
What are the characteristics of viruses as carriers?
May have carriers without symptoms
What are the notable infectious diseases of the 21st century mentioned in the text?
COVID-19, SARS, Swine flu, MERS, Ebola, and Zika virus
How does Reverse Transcription PCR (RT-PCR) differ from conventional PCR?
RT-PCR utilizes RNA as the starting template and involves a reverse transcription step.
What role does histochemical staining play in microbial detection within tissue?
Histochemical staining allows for the visualization and localization of microbes in stained tissue.
Under what circumstance can histochemical staining be considered beneficial in microbial detection?
When advanced molecular techniques are the primary diagnostic tools.
In the context of pathogenic bacteria interactions, which classification is given to bacteria that establish relationships where both the bacteria and host cells benefit?
Mutualistic interactions
What distinguishes commensal interactions from mutualistic interactions in the context of bacteria-host relationships?
Mutualistic interactions lead to neutral outcomes for both bacteria and host cells.
How are bacteria classified in interactions where they cause harm to host cells?
Pathogenic interactions
What role do cytokines play in the initiation of a cytokine storm, particularly in the context of a severe inflammatory response?
Cytokines orchestrate an excessive and dysregulated immune response, leading to a cytokine storm.
How can a cytokine storm impact various organ systems beyond the site of infection, contributing to severe complications?
Excessive cytokine release can lead to systemic inflammation, affecting multiple organ systems.
What distinguishes the genome organization of SARS-CoV-2 from other viruses?
SARS-CoV-2 has a single-stranded RNA genome with the entire genetic information on one strand.
What is the role of the 'spike-like' proteins on the surface of SARS-CoV-2?
They facilitate the attachment of the virus to receptors on human cells.
How does the fusion of the virus membrane with the human cell membrane contribute to the infection process of SARS-CoV-2?
It enables the viral genome to enter the host cell and initiate replication.
Which specific cellular receptor is targeted by the spike (S) protein of SARS-CoV-2 during the viral entry process, and where is this receptor primarily expressed?
Angiotensin-converting enzyme 2 (ACE2), primarily expressed in cells of the respiratory tract.
What role does the host cell protease TMPRSS2 play in the viral entry process of SARS-CoV-2?
TMPRSS2 cleaves the spike protein, exposing a fusion peptide.
fter the fusion of the viral membrane with the host cell membrane, what is the immediate consequence for the viral genetic material?
The viral genetic material is released into the host cell cytoplasm.
How can lytic viruses trigger cell death in host cells, and what is a potential consequence of this process?
By triggering necrosis, potentially causing inflammation and tissue damage
In the context of viral pathogenesis, how do lytic viruses primarily contribute to the destruction of host cells?
By inducing programmed cell death (apoptosis)
What role does the induction of apoptosis in major immune cells play in persistent viral infections?
It acts as a mechanism of immunosuppression.
Study Notes
Impact of Infectious Diseases
- The 21st century has seen outbreaks of several severe infectious diseases, including COVID-19, SARS, Swine flu, MERS, Ebola, and Zika virus.
- Viruses are small genetic code collections surrounded by a protein coat and cannot replicate alone; they cause damage to the host organism and may have carriers without symptoms.
- Viral pathogenesis involves five stages: entry, local replication, dissemination, shedding, and onward transmission to a third host.
- Viruses can cause local or systemic disease, destroy host cells, and induce cell death or immunosuppression.
- SARS-CoV-2 is a single-stranded RNA virus with "crown-like" particles and spike proteins that allow it to enter human cells.
- Mechanisms of SARS-CoV-2 viral entry involve the fusion of the virus membrane with the human cell membrane, allowing the viral genome to enter and replicate within the host cell.
- Long COVID occurs due to the pathophysiological processes associated with COVID-19.
- Polymerase Chain Reaction (PCR) is used for gene cloning, gene mutagenesis, functional gene analysis, diagnosis and monitoring of hereditary diseases, and detection of microorganisms.
- Reverse Transcription PCR targets RNA and is used for the same purposes as PCR, but it starts with a reverse transcription step.
Test your knowledge on the impact of infectious diseases with this quiz. Explore viral pathogenesis, SARS-CoV-2 mechanisms, and the use of PCR for diagnosis and monitoring. Dive into the world of infectious diseases and their effects on human health.
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