Detection of Diseases: COVID-19 Testing
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Questions and Answers

What is the primary purpose of the ELISA technique described?

  • To amplify nucleic acids for detection
  • To separate proteins based on their charge
  • To detect specific viral antigens in a patient sample (correct)
  • To determine the size of proteins in a sample

Which step in the Western blotting process is crucial for the specific detection of the target protein?

  • Exposing the membrane to a specific antibody (correct)
  • Washing the membrane with buffer solution
  • Transferring proteins to a membrane
  • Separation of the proteins using gel electrophoresis

What mechanism does PCR utilize to detect nucleic acids?

  • Hybridization of antibodies with proteins
  • Electrophoresis for size separation
  • Amplification of specific DNA sequences (correct)
  • Colorimetric detection of proteins

What advantage do rapid tests provide in the context of detecting viral infections?

<p>They provide immediate results without laboratory equipment. (B)</p> Signup and view all the answers

In an ELISA test, what happens after the addition of enzyme-bound secondary antibodies?

<p>A color change occurs due to the substrate addition. (D)</p> Signup and view all the answers

What is confirmed by the presence of the red line at the Control Line in an antigen rapid test?

<p>The test is valid and worked properly. (C)</p> Signup and view all the answers

What happens if the red line at the Control Line does not appear during an antibody test?

<p>The entire test is deemed invalid. (B)</p> Signup and view all the answers

In the process of RT-PCR, what is the first step after RNA extraction?

<p>Reverse transcription. (A)</p> Signup and view all the answers

How does a TaqMan probe function in real-time PCR?

<p>It releases fluorescent signals upon degradation during PCR. (B)</p> Signup and view all the answers

What characterizes rapid tests like antigen tests?

<p>Results can be seen with the naked eye within 15 minutes. (D)</p> Signup and view all the answers

During the RT-PCR process, what role does the Taq polymerase play in the assay?

<p>It ensures the degradation of the TaqMan probe. (B)</p> Signup and view all the answers

What is the purpose of primer annealing during PCR amplification?

<p>To allow primers to bind to the target DNA. (B)</p> Signup and view all the answers

In the context of nucleic acid detection, what is cDNA?

<p>Complementary DNA synthesized from RNA. (C)</p> Signup and view all the answers

What does the control line in a test kit indicate?

<p>The test kit has not expired (C)</p> Signup and view all the answers

Which component in the test kits binds to the Covid-19 IgG or IgM?

<p>Mouse Anti-Human IgM or IgG antibody (A)</p> Signup and view all the answers

What is the main advantage of Antigen Rapid Tests for COVID-19 detection?

<p>They simplify the testing process for home use (A)</p> Signup and view all the answers

What type of interaction do antigen rapid tests primarily rely on?

<p>Immunological antigen-antibody interaction (D)</p> Signup and view all the answers

Which component is primarily responsible for maintaining the stability of the sample in the test kit?

<p>Buffer solution (C)</p> Signup and view all the answers

What is the role of the Gold-Rabbit IgG conjugate in the test kits?

<p>To move along the liquid and bind to anti-rabbit IgG (A)</p> Signup and view all the answers

In the test process, what happens if the patient's sample contains the virus?

<p>Red lines will appear on the corresponding M or G line (C)</p> Signup and view all the answers

Which of the following does not contribute to the action of antigen rapid tests?

<p>Complex laboratory analysis (D)</p> Signup and view all the answers

Which shape of bacteria is classified as 'cocci'?

<p>Spherical (D)</p> Signup and view all the answers

What is a common method by which pathogenic bacteria cause disease?

<p>Releasing toxins into the bloodstream (C)</p> Signup and view all the answers

Which of the following is NOT a use of bacteria?

<p>Causing food poisoning (C)</p> Signup and view all the answers

What characteristic do viruses lack compared to living organisms?

<p>Ability to reproduce on their own (B)</p> Signup and view all the answers

What is the role of bacteria in human health?

<p>Digesting food and making vitamins (B)</p> Signup and view all the answers

Which of the following diseases is commonly caused by bacteria?

<p>Cholera (A)</p> Signup and view all the answers

What component do bacteria have that makes up their cell wall?

<p>Peptidoglycan (A)</p> Signup and view all the answers

What process describes how nitrogen-fixing bacteria support plant life?

<p>Changing nitrogen gas into ammonia (B)</p> Signup and view all the answers

What is a significant consequence of antibiotic use in bacteria?

<p>Bacteria develop resistance to antibiotics (D)</p> Signup and view all the answers

Which mechanism is NOT utilized by antivirals to combat viral infections?

<p>Killing the virus permanently (A)</p> Signup and view all the answers

What is the primary role of vaccines in infectious disease prevention?

<p>Stimulate the immune system to produce antibodies (D)</p> Signup and view all the answers

Which of the following describes a true zone of inhibition in antibiotic testing?

<p>A clear, large area with minimal bacterial growth (C)</p> Signup and view all the answers

Which antiviral drug is specifically used to treat the flu virus?

<p>Zanamivir (C), Oseltamivir (D)</p> Signup and view all the answers

What is a common feature of both antibiotic and antiviral resistance?

<p>Resistance can lead to ineffective treatments (D)</p> Signup and view all the answers

What does it mean when an antiviral only shortens symptoms by 1-2 days?

<p>It does not provide a long-term solution to the infection (A)</p> Signup and view all the answers

How do vaccines allow the body to respond effectively to future infections?

<p>By tricking the immune system to recognize pathogens (A)</p> Signup and view all the answers

What is the main outcome of the lytic cycle in viral replication?

<p>The host cell is killed and bursts, releasing new viruses. (C)</p> Signup and view all the answers

Which process differentiates the lysogenic cycle from the lytic cycle?

<p>The viral nucleic acid integrates into the host's chromosome. (C)</p> Signup and view all the answers

What type of genetic material do all viruses possess at their core?

<p>Nucleic acids (DNA or RNA) (C)</p> Signup and view all the answers

How do antibiotics function in the treatment of infections?

<p>They kill only bacteria and do not affect viruses. (C)</p> Signup and view all the answers

Which of the following diseases is caused by a virus?

<p>Chickenpox (B)</p> Signup and view all the answers

Which statement about the viral structure is true?

<p>All viruses possess a protein coat called a capsid. (C)</p> Signup and view all the answers

What is the primary role of antivirals in treating infections?

<p>To specifically inhibit the replication of viruses. (C)</p> Signup and view all the answers

Which of the following represents a characteristic of the lysogenic cycle?

<p>Formation of a provirus that replicates with the host cell. (D)</p> Signup and view all the answers

Flashcards

ELISA

A laboratory technique used to detect the presence and concentration of specific viral antigens in a sample.

Western Blot

A laboratory technique used to detect a specific protein in a blood or tissue sample.

Viral Antigen

A molecule found on the surface of a virus.

ELISA Steps (simplified)

A process with multiple steps involving antibodies, antigens and washes to determine the presence of an antigen.

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Gel Electrophoresis

Technique used to separate proteins based on their size.

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Rapid Test

A diagnostic test that provides results quickly, typically within 15 minutes, using the naked eye.

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Negative Result (Rapid Test)

A result indicating no presence of the target substance or disease in a rapid test. Absence of a red line at the Control Line in a rapid test indicates negative results.

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RT-PCR

Reverse Transcription Polymerase Chain Reaction. This technique converts RNA into DNA and then amplifies that DNA. It is used to detect the presence of specific genetic material.

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TaqMan PCR

A type of Real-Time PCR that uses probes to detect amplified DNA products. The probes only bind if DNA is amplified, enabling real time monitoring of amplification.

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Control Line

A control line in a rapid test that verifies the test process accuracy, ensuring the test worked as expected. A red line in this area confirms the test's validity.

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Nucleic Acid Probe

A single-stranded piece of DNA or RNA that is complementary to a specific DNA sequence in the sample. It is labelled with fluorescent markers to enable detection.

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Quenching

A reduction in fluorescence caused by the closeness of two fluorescent molecules.

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Taq Polymerase

A heat-stable DNA polymerase enzyme used in PCR to synthesize new DNA strands from a template.

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How do antibody tests work?

Antibody tests detect the presence of antibodies produced by your immune system in response to a specific virus, like COVID-19. They use a sample (like blood) to check for antibodies against the virus.

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What is an antigen?

An antigen is a substance that triggers an immune response in the body. It's often a molecule found on the surface of a virus or bacteria.

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What is an antibody?

An antibody is a protein produced by the immune system to fight off specific antigens.

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How do antigen tests work?

Antigen tests detect the presence of viral proteins (antigens) in a sample, like a nasal swab. If the virus is present, its antigens will bind with antibodies on the test strip.

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What is ATK?

ATK stands for Antigen Rapid Test, a type of COVID-19 test that can be done at home.

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Why are ATK tests useful?

ATK tests are useful for quick and easy detection of COVID-19, especially for people who may have mild symptoms or need frequent testing.

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What is the principle behind ATK tests?

ATK tests work based on antigen-antibody interaction. The test contains antibodies that bind to specific viral antigens. This binding is detected using a color change on the test strip.

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What is Saliva-Based Testing?

Saliva-based tests use your spit instead of a nasal swab to detect the presence of COVID-19 antigens.

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Viral Structure

Viruses have a simple structure consisting of a protein coat (capsid) surrounding their genetic material (DNA or RNA).

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Host Cell

A living cell that a virus needs to replicate and multiply. Viruses can invade human, animal, plant, and even bacterial cells.

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Viral Specificity

Each virus has a specific type of cell it can infect. For example, HIV only infects human T cells.

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Lytic Cycle

A viral replication cycle where the virus takes over the host cell, replicates rapidly, and then bursts the cell, releasing new viruses.

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Lysogenic Cycle

A viral replication cycle where the virus's genetic material integrates into the host cell's DNA and replicates silently along with it.

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Viruses and Disease

Viruses can cause a variety of diseases in humans, animals, plants, and even bacteria. Examples include the common cold, influenza, and AIDS.

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Antibiotics vs. Antivirals

Antibiotics are drugs that kill bacteria, while antivirals are drugs that treat viral infections.

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Vaccination

A way to protect against diseases by introducing weakened or inactive forms of a pathogen to stimulate the body's immune system.

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What are bacteria?

Bacteria are single-celled organisms that are found everywhere on Earth. They are essential for many processes like decomposition and food production.

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How do bacteria reproduce?

Bacteria reproduce asexually through a process called binary fission. This means one bacterium divides into two identical daughter cells.

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What is peptidoglycan?

Peptidoglycan is a unique substance found in bacterial cell walls. It provides structure and support to the bacterial cell.

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What are the shapes of bacteria?

Bacteria come in three main shapes: spherical (cocci), rod-shaped (bacilli), and spiral (spirilla).

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What are viruses?

Viruses are tiny particles that can cause disease. They are not considered living organisms because they cannot reproduce on their own.

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How do viruses reproduce?

Viruses reproduce by injecting their genetic material (DNA or RNA) into a host cell. They then use the host cell's machinery to make more viruses.

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What is virology?

Virology is the study of viruses, including their structure, function, and how they cause disease.

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What are some uses of bacteria?

Bacteria are incredibly versatile! They are used in food production (yogurt, cheese), decomposition, and medicine.

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Antibiotics

Drugs that target specific structures in bacteria to kill them. They were originally derived from fungi (like penicillin) but are now mostly made synthetically.

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Antibiotic Resistance

When bacteria become immune to a specific antibiotic and are no longer killed by it, making the antibiotic ineffective.

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Antivirals

Medicines used to treat certain viral infections, not permanently killing or disarming the virus, but shortening symptoms.

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Antiviral Resistance

When viruses become resistant to a specific antiviral drug, making it less effective in treating the infection.

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How do Antivirals work?

Antiviral drugs work in several ways: by blocking virus entry into cells, boosting the immune system, or reducing the amount of active virus in the body.

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Vaccines

Substances used to prevent infections (both viral and bacterial) from causing disease, by training the immune system to recognize and fight the pathogen.

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How do Vaccines work?

Vaccines 'trick' the immune system into making antibodies against specific pathogens, so it's ready to fight them off if the real pathogen enters the body.

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Antibodies

Proteins made by the immune system that bind to and destroy foreign invaders like bacteria and viruses.

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Study Notes

Detection of Diseases

  • Specificity of Antibodies: Antibodies react specifically to only one antigen.
  • Agglutination Reaction (Blood Testing): An antigen-antibody reaction where particles clump together. This is used in blood typing.
    • If antibody and antigen do not match, no agglutination occurs.
    • If antibody and antigen do match, agglutination occurs.
  • COVID-19 Progression & Antibodies:
    • IgM and IgG are antibodies.
    • IgM is found in the lymphatic system.
    • IgG is found in various parts of the body.
    • IgM rises faster and peaks earlier than IgG in response to infection.
  • COVID-19 Testing:
    • Molecular Test: Measures the amount of viral RNA.
    • Antibody Test: Measures the immune response to the virus.
  • Serological Tests (Antibody Tests): Determine the presence of COVID-19-specific antibodies (mainly IgM and IgG).
    • IgM and IgG are the first-line responses to viral infections.
    • Rapid tests (lateral flow assays) can detect antigen-specific antibodies in serum within 30 minutes.
    • These tests are beneficial due to low sample volume requirements, fast turnaround time, simplicity, and low cost.
  • SARS-CoV-2 Rapid IgG-IgM Test:
    • Uses two mouse anti-human monoclonal antibodies (anti-IgG and anti-IgM).
    • Surface antigen from SARS-CoV-2 is conjugated to colloidal gold nanoparticles.
  • COVID-19 Testing Results:
    • Negative: No COVID-19, no line on T site.
    • IgM Positive: Early infection.
    • IgG Positive: Later infection.
    • IgM/IgG Positive: Between early and later infection.
  • Antigen Test Kits (ATK):
    • Simplified testing method for home use.
    • Requires a swab, a test strip, and a saline solution.
    • Uses antigen-antibody interactions to detect the virus.
  • Principle behind ATK: - Detection of SARS-CoV-2 virus based on antigen-antibody interaction - Antigen is SARS-CoV-2 and antibody is a protein. - Antibodies are naturally produced by the immune system.
  • Test Strip Mechanism: The test strip contains antibodies specific to COVID-19.
    • If the virus is present, it binds to the antibody, causing a visible red line to appear.
    • If no virus is present, the antibodies will only bind to antibodies on the control line.
  • Covid Tests using RT-PCR (Reverse Transcription Polymerase Chain Reaction):
    • Uses a molecular method to detect RNA
    • First viral inactivation or direct lysis with detergent
    • RNA extraction
    • cDNA synthesis
    • PCR amplification.
    • Detect viral RNA
    • Real time detection by fluorescent signal.
  • TaqMan PCR: A type of real-time PCR that uses labeled nucleic acid probes.
  • Enzyme-Linked Immunosorbent Assay (ELISA): Measures analyte concentration (antibodies or antigens) in solution.
    • Antigen recognized by specific antibody.
    • Antibody recognized by a secondary antibody with an enzyme attached.
  • ELISA Types:
    • Direct
    • Indirect
    • Sandwich
    • Competitive
  • Western Blot: Detects specific proteins in samples (blood or tissue), using electrophoresis and antibodies.

Timeline of COVID-19 Tests

  • The timeline varies for PCR and antibody tests, depending on when the infection occurred.

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Related Documents

Chapter 6 Detection of Diseases PDF
Bacteria and Viruses PDF

Description

Explore the mechanisms of disease detection through antibody specificity and the agglutination reaction in blood testing. This quiz delves into COVID-19 testing methods, including molecular and serological tests, and explains the roles of IgM and IgG antibodies in the immune response. Test your knowledge on how these factors are crucial for understanding disease progression and diagnosis.

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