Podcast
Questions and Answers
Which of the following is NOT a characteristic of viruses?
Which of the following is NOT a characteristic of viruses?
- They can be classified based on their genetic material (DNA or RNA).
- They can cause a variety of diseases in living organisms.
- They can replicate independently of a host cell. (correct)
- They are acellular, meaning they lack a cell structure.
What is the primary function of the capsid in a virus?
What is the primary function of the capsid in a virus?
- It provides the energy for viral replication.
- It contains the viral genetic material.
- It protects the virus from the host's immune system. (correct)
- It helps the virus attach to a host cell.
What is the difference between a DNA virus and an RNA virus?
What is the difference between a DNA virus and an RNA virus?
- DNA viruses are more complex than RNA viruses.
- DNA viruses use DNA as their genetic material, while RNA viruses use RNA. (correct)
- DNA viruses can only infect animal cells, while RNA viruses can infect plant cells.
- DNA viruses are more likely to cause disease than RNA viruses.
How do viruses contribute to evolution?
How do viruses contribute to evolution?
During the viral replication process, which step involves the viral genetic material entering the host cell?
During the viral replication process, which step involves the viral genetic material entering the host cell?
What is the primary mode of transmission for HIV?
What is the primary mode of transmission for HIV?
How does HIV affect the body?
How does HIV affect the body?
What is the primary reason that vaccine development for HIV has been challenging?
What is the primary reason that vaccine development for HIV has been challenging?
Which of the following is NOT a stage of HIV infection?
Which of the following is NOT a stage of HIV infection?
Flashcards
HIV Definition
HIV Definition
HIV is a retrovirus that attacks the immune system, particularly CD4+ T-cells.
HIV Transmission Modes
HIV Transmission Modes
HIV spreads through direct contact with infected bodily fluids like blood, semen, and breast milk.
Stages of HIV Infection
Stages of HIV Infection
HIV infection has three stages: Acute (flu-like), Chronic (asymptomatic), and AIDS (immune failure).
Antiretroviral Therapy (ART)
Antiretroviral Therapy (ART)
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Prevention Methods for HIV
Prevention Methods for HIV
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Acellular
Acellular
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Capsid
Capsid
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Viral Life Cycle
Viral Life Cycle
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DNA vs. RNA Viruses
DNA vs. RNA Viruses
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Ecological Role of Viruses
Ecological Role of Viruses
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Study Notes
Viral Structure and Nature
- Viruses are not alive or dead; they are acellular entities.
- Composed of a protein coat (capsid) enclosing genetic material (DNA or RNA).
- Lacking organelles like mitochondria, ribosomes, and a nucleus.
- Exist as single particles called virions.
- Lack cell walls but have a protective protein coat (capsid) and some with lipid envelopes.
- Neither autotrophic nor heterotrophic; they invade host cells to replicate.
Viral Replication
- Viruses invade host cells through a step-by-step process.
- Attachment: The virus attaches to the host cell.
- Penetration: The virus injects its genetic material.
- Hijacking: The virus controls the host's machinery to replicate.
- Assembly: New viral particles are created.
- Release: The host cell bursts, releasing new viruses.
Viral Classification
- Classified based on genetic material:
- DNA viruses (e.g., Herpesvirus).
- RNA viruses (e.g., Influenza virus).
- Retroviruses (e.g., HIV), which use RNA but convert to DNA.
Viral Roles in Ecosystems
- Regulate populations of bacteria and microorganisms.
- Facilitate gene transfer between organisms, contributing to evolution.
- Play a role in marine ecosystems, controlling algae blooms and releasing nutrients.
Viral Diseases
- Cause diseases in humans, animals, and plants. Examples include:
- Human: Influenza, HIV/AIDS, COVID-19, Chickenpox.
- Animal: Rabies, Avian flu.
- Plant: Tobacco Mosaic Virus (TMV).
Viral Treatment and Prevention
- Vaccines train the immune system to fight viruses without illness.
- Antiviral medications stop viral replication, not kill the virus itself.
- Examples: Tamiflu (flu), Antiretrovirals (HIV).
- Prevention tips include handwashing, mask-wearing, and not sharing items with sick individuals.
HIV: A Specific Retrovirus
- HIV is a retrovirus that carries its genetic material as RNA.
- Specific to humans, targeting CD4+ T-cells (immune cells).
- Composed of a protein capsid and a lipid envelope that enables attachment to human cells.
- Transmitted through direct contact with infected bodily fluids, not casually. Includes:
- Blood
- Semen
- Vaginal fluids
- Breast milk
- HIV weakens the immune system by infecting and destroying CD4+ T-cells.
- HIV infection stages:
- Acute: Flu-like symptoms, high viral load.
- Chronic: Low-level viral reproduction, may last years.
- AIDS: Severe immune damage, vulnerability to infections/cancers.
HIV Treatment and Prevention
- Antiretroviral Therapy (ART) controls HIV, allowing immune system recovery.
- Pre-exposure prophylaxis (PrEP) and post-exposure prophylaxis (PEP) are preventive measures.
HIV's Societal Impact
- Significant workforce and healthcare costs.
- Burden on families and education systems.
- Economic impact and potential for stigma.
Importance of Early HIV Testing
- Early detection is crucial for timely treatment to maintain health.
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