Structure and Classification of Viruses

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Questions and Answers

What are the major components of a virus that distinguish it from other cellular organisms?

Cytoplasm and ribosomes

Capsid and genetic material (correct)

Cell membrane and nucleus

Chloroplasts and cell walls

What is the standard system for classifying viruses based on their characteristics?

International Committee on Taxonomy of Viruses (ICTV) (correct)

Linnaean taxonomy

USDA classification system

Bergey's Manual

Which of the following statements about viral replication is correct?

Viral replication results in the release of new virions into the host environment. (correct)

All viruses undergo the same replication process regardless of type.

Viral replication occurs in a fixed sequence of five non-overlapping steps.

Viral replication can occur only in prokaryotic cells.

What is primarily responsible for the ability of viruses to cause diseases in hosts?

Their interaction with the host’s immune response Signup and view all the answers

Which viral illness is NOT correctly matched with the disease it causes?

HIV - Hepatitis Signup and view all the answers

What is the difference between vaccinations and anti-viral drugs?

Vaccinations build immunity while anti-viral drugs treat existing infections. Signup and view all the answers

What is a prion and its primary characteristic?

An infectious agent composed of protein only Signup and view all the answers

Which factor significantly contributes to the development of 'super bugs'?

Overuse of broad-spectrum antibiotics Signup and view all the answers

How do biofilms contribute to foodborne diseases?

Biofilms create a protective environment for pathogenic bacteria. Signup and view all the answers

What distinguishes a plague from an epidemic?

A plague typically refers to a specific disease with higher mortality rates. Signup and view all the answers

What is MRSA primarily characterized by?

Resistance to methicillin and other antibiotics Signup and view all the answers

Which factor contributes to the importance of antibiotic resistance in relation to MRSA?

It leads to more lethal strains emerging. Signup and view all the answers

Without antibiotic resistance, which statement is true about MRSA's existence?

The bacteria would be easily treatable and less prevalent. Signup and view all the answers

In terms of environmental balance, which role do fungi play?

Fungi help decompose organic matter. Signup and view all the answers

How are fungi involved in the pharmaceutical industry?

They produce antibiotics and other medicinal compounds. Signup and view all the answers

Which statement accurately describes a model organism?

It is a species used for research due to its ease of manipulation. Signup and view all the answers

Why is fungi considered a significant model organism?

They exhibit rapid growth and unique genetic properties. Signup and view all the answers

Which types of fungal infections are typically classified as opportunistic?

Those occurring in the lungs in immunocompromised individuals. Signup and view all the answers

How do fungi contribute to the chemical industry?

They are used for bioremediation of pollutants. Signup and view all the answers

Are all fungal infections treated using the same therapeutic approach?

No, treatments differ significantly depending on infection type. Signup and view all the answers

Study Notes

Structure and Shape of Viruses

Viruses consist of nucleic acid (DNA or RNA) encased in a protein coat called a capsid.
Some viruses have an additional lipid envelope derived from the host cell membrane.
Virus shapes include helical, icosahedral, and complex structures.

Components of a Virus

Big components include the viral nucleic acid and capsid.
Small components are accessory proteins that may aid in infection or immune evasion.

Commonalities with Cells

All cells, including viruses, must replicate and use genetic material.
Rank of cells from largest to smallest: Eukaryotic cells, Prokaryotic cells, Viruses.

Classification of Viruses

Viruses differ by type of nucleic acid, capsid shape, and envelope presence.
Standard classification system includes Baltimore classification based on nucleic acid type and replication methods.
Not all viruses can be classified; some may lack sufficient characteristics.

Viral Replication Steps

Steps include Attachment, Entry, Integration (for some), Replication, Assembly, and Release.
Each step involves specific interactions with host cells, leading to the production of new virus particles.
Some viruses replicate via lytic cycles, while others may utilize lysogenic cycles.

Transmission of Viruses

Viruses are transmitted through direct contact, droplets, or vectors.
Diseases result from viral replication harming host cells or inducing immune responses.
Not all viruses cause diseases; some may be benign or asymptomatic.

Major Viral Illnesses

Common viral illnesses include Influenza, HIV/AIDS, Hepatitis, Measles, and COVID-19.
Viruses may be misclassified; correct matching is important for treatment and understanding.
The severity of certain viruses is linked to factors like mutation rates and transmission methods.
The coronavirus originated from zoonotic sources, often linked to bats.
COVID-19 proved hard to combat due to rapid transmission, asymptomatic cases, and mutation.

Vaccinations vs. Anti-Viral Drugs

Vaccinations stimulate immune response creating memory cells against pathogens.
Anti-viral drugs inhibit viral replication or block specific stages of the viral life cycle.
Vaccinations prevent infection, while anti-viral drugs treat already infected individuals.

Prions

Prions are infectious proteins that trigger abnormal folding of normal proteins in the brain.
Composed solely of misfolded proteins, lacking nucleic acids.
Prions cause neurodegenerative disorders leading to brain damage.

Bacterial Diseases and Historical Impact

Common bacterial diseases include Tuberculosis, Plague, Cholera, and Syphilis, identifiable by their structures.
Worst bacterial diseases have historically caused significant mortality and morbidity.
Plague refers to specific outbreaks with high mortality; epidemics imply widespread disease spread.
Common bacterial causes of plagues include those responsible for past pandemics.

Biofilms and Foodborne Diseases

Biofilms are communities of microorganisms adhering to surfaces, often protecting bacteria from antibiotics.
Foodborne diseases can originate from bacteria, viruses, or parasites.
The relationship between biofilms and foodborne diseases stems from biofilms' ability to harbor pathogens.

Super Bugs and Antibiotic Resistance

Superbugs are antibiotic-resistant bacteria, with MRSA being a prominent example.
Overuse of or reliance on broad-spectrum antibiotics contributes to the development of superbugs.
Superbugs may be more contagious, complicating infection control.
Limiting unnecessary antibiotic use is a better preventive approach against superbugs.

Importance of MRSA

MRSA (Methicillin-Resistant Staphylococcus aureus) is resistant to multiple antibiotics.
Antibiotic resistance complicates treatment and increases the risk of severe infections.
Without antibiotic resistance, MRSA would likely not exist in its current form.
Other resistant strains, like VRE, show similar challenges to MRSA.
MRSA has the potential to evolve further under selective pressure from antibiotic use.

Environmental Role of Fungi

Fungi play a vital role in nutrient cycling and decomposition processes in ecosystems.
Survival without fungi would be unsustainable, as they decompose organic matter.
Fungi are most closely related to animal cells, sharing eukaryotic features.

Fungi in Chemical and Pharmaceutical Industries

Fungi are utilized in producing enzymes, antibiotics (like penicillin), and fermentation products.
Alternatives to fungi exist but may not match effectiveness in pharmaceuticals.
Microscopy techniques like staining and electron microscopy allow in-depth observation of fungi.

Role of Fungi as Model Organisms

Model organisms are species extensively studied to understand biological processes.
Fungi serve as model organisms due to their rapid growth and genetic tractability.
Other model organisms include yeast, mice, and fruit flies.

Types of Fungal Infections in Humans

Types of fungal infections include superficial, cutaneous, systemic, and opportunistic infections.
Differences between types often arise from the affected area and infection modes.
Treatment varies based on the infection type, with some requiring targeted antifungals.
Opportunistic lung infections include Aspergillosis and Pneumocystis pneumonia, differing in causative agents and susceptibility.

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Description

This quiz explores the fundamental structure, components, and classification methods of viruses. Key topics include virus shapes, replication steps, and viral similarities to cells. Test your understanding of the unique characteristics that define different types of viruses.