Join with a free account for more service, or become a member for full access to exclusives and extra support of WorldSupporter >>

Image

What is a virus?

A virus is a tiny, infectious agent that can only reproduce inside the living cells of an organism. Viruses are much smaller than bacteria and far simpler in structure. They lack the machinery needed to replicate on their own and rely on host cells to provide the necessary resources.

  • Viruses come in various shapes and sizes, but all share some common features:
    • Genetic material: They contain either DNA or RNA as their genetic material, but never both.
    • Protein capsid: A protective protein shell surrounds the genetic material.
    • (Some viruses also have an) Envelope: A membranous layer derived from the host cell surrounds the capsid in some viruses.

What are the main features of a virus?

  • Obligate parasites: Viruses cannot reproduce on their own. They invade host cells, hijack cellular machinery, and use it to produce new viral particles.
  • Specificity: Different viruses have specific host ranges, meaning they can only infect particular types of cells or organisms.
  • High mutation rate: Viral genomes can mutate rapidly, allowing them to evolve and evade host defenses.

Why is a virus important?

  • Viruses are the most abundant biological entity on Earth and play a significant role in ecosystems.
  • They cause a wide range of diseases in humans, animals, and plants, impacting global health and agriculture.
  • Studying viruses is crucial for developing vaccines, antiviral drugs, and understanding fundamental biological processes.

What are the applications of a virus in practice?

  • Vaccinations: Vaccines work by exposing the body to weakened or inactive forms of a virus, stimulating the immune system to develop immunity and prevent future infections.
  • Gene Therapy: Viral vectors, modified viruses, can be used to deliver therapeutic genes into cells for treating genetic diseases.
  • Phage Therapy: Certain viruses (bacteriophages) specifically target and kill bacteria. This approach is being explored as an alternative to antibiotics for combating antibiotic-resistant infections.

Practical example

  • The common cold is a classic example of a viral disease. Rhinoviruses, belonging to a group of single-stranded RNA viruses, are the most frequent culprits. These viruses infect the upper respiratory tract, causing symptoms like runny nose, sore throat, and coughing.

Critical comments

  • Viral infections can range from mild to life-threatening, and some viruses lack effective treatments.
  • The rapid evolution of viruses poses a constant challenge in developing vaccines and antiviral drugs.
  • The misuse of viral vectors in gene therapy raises biosafety concerns.

Image  Image  Image  Image

Access: 
Public

Image

Click & Go to more related summaries or chapters:

Study Guide with flashcards and definitions with Genomics at Utrecht University

Flashcards and definitions with Genomics

Online flashcards with Genomics

  • Centromere
  • Chromatides
  • Chromosomes
  • Sex chromosomes
  • Asexual reproduction
  • Sexual reproduction
  • Mitosis
  • Meiosis
  • Genomics
  • Transcriptomics
  • Proteomics
  • Metabolomics
  • Plasmid
  • Polymerase Chain Reaction
  • Next Generation Sequencing
  • Sanger sequencing
  • RNA-sequencing
  • CRISPR-Cas9
  • Forward genetic screens
  • Reverse genetic screens
  • RNA interference
  • Bioinformatics
  • DNA replication
  • DNA mutation
  • Evolution
  • Horizontal gene transfer (HGT)
  • Virus
  • Microsatellites
  • Basic Local Alignment Search Tool (BLAST)
  • Findable, Accessible, Interoperable, and Reusable data (FAIR data)
  • Phylogenetic tree
  • Insertion
  • Deletion
  • For flashcards and definitions, see the supporting content of this study guide
Access: 
Public
This content refers to .....
Summaries and Study Assistance - Start

Summaries and Study Assistance - Start

Summaries, study notes, tips and tools for study and know how

For optimal and free use of summaries, study help, exam tickets, practice exams, bullet points notes

  •     join JoHo WorldSupporter
  •     then check the study and exam tips;
  •     study the material through the summaries;
  •     repeat the material through the bullets or notes
  •     master the material through the practice exams.
...Read more
Image

Image

Follow the author: Hugo
Work for WorldSupporter

Image

JoHo can really use your help!  Check out the various student jobs here that match your studies, improve your competencies, strengthen your CV and contribute to a more tolerant world

Working for JoHo as a student in Leyden

Parttime werken voor JoHo

Comments, Compliments & Kudos:

Add new contribution

CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Image CAPTCHA
Enter the characters shown in the image.

Image

Check how to use summaries on WorldSupporter.org

Online access to all summaries, study notes en practice exams

How and why would you use WorldSupporter.org for your summaries and study assistance?

  • For free use of many of the summaries and study aids provided or collected by your fellow students.
  • For free use of many of the lecture and study group notes, exam questions and practice questions.
  • For use of all exclusive summaries and study assistance for those who are member with JoHo WorldSupporter with online access
  • For compiling your own materials and contributions with relevant study help
  • For sharing and finding relevant and interesting summaries, documents, notes, blogs, tips, videos, discussions, activities, recipes, side jobs and more.

Using and finding summaries, study notes en practice exams on JoHo WorldSupporter

There are several ways to navigate the large amount of summaries, study notes en practice exams on JoHo WorldSupporter.

  1. Use the menu above every page to go to one of the main starting pages
    • Starting pages: for some fields of study and some university curricula editors have created (start) magazines where customised selections of summaries are put together to smoothen navigation. When you have found a magazine of your likings, add that page to your favorites so you can easily go to that starting point directly from your profile during future visits. Below you will find some start magazines per field of study
  2. Use the topics and taxonomy terms
    • The topics and taxonomy of the study and working fields gives you insight in the amount of summaries that are tagged by authors on specific subjects. This type of navigation can help find summaries that you could have missed when just using the search tools. Tags are organised per field of study and per study institution. Note: not all content is tagged thoroughly, so when this approach doesn't give the results you were looking for, please check the search tool as back up
  3. Check or follow your (study) organizations:
    • by checking or using your study organizations you are likely to discover all relevant study materials.
    • this option is only available trough partner organizations
  4. Check or follow authors or other WorldSupporters
    • by following individual users, authors  you are likely to discover more relevant study materials.
  5. Use the Search tools
    • 'Quick & Easy'- not very elegant but the fastest way to find a specific summary of a book or study assistance with a specific course or subject.
    • The search tool is also available at the bottom of most pages

Do you want to share your summaries with JoHo WorldSupporter and its visitors?

Quicklinks to fields of study for summaries and study assistance

Field of study

Check the related and most recent topics and summaries:
Activity abroad, study field of working area: