1 / 15

Viruses: Living or Not?

Viruses: Living or Not?. Virus . Biological particles that are NOT made of cells Viral particles are extremely small in size Don’t eat, respire or respond to their environment (No metabolism) Parasitic: they requires host Host is an organism that shelters and nourishes something

arich
Télécharger la présentation

Viruses: Living or Not?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Viruses: Living or Not?

  2. Virus Biological particles that are NOT made of cells • Viral particles are extremely small in size • Don’t eat, respire or respond to their environment (No metabolism) • Parasitic: they requires host • Host is an organism that shelters and nourishes something • Host provides the virus with all the materials needed to make copies of itself can NOT reproduce on its own • Therefore viruses are considered to be non- living

  3. What is a virus? TERMS you need to know • Pathogen: something that causes an illness • All viruses are pathogens • Not all pathogens are viruses – some bacteria can cause illnesses – you to become sick • Vector: how a virus gets into a host’s cell it wants to infect/use. Think of it’s the viruses key to get into the cell lock. • Viruses infect/attack specific cells (ex: HIV attacks immune cells, Flu virus infects throat, ear and nose cells) • Transmission: the passing of the virus from one organisms to another • Bacteriophage: a virus that attacks bacteria cells

  4. Characteristics of Viruses • Virus is a Latin word = virus • Not composed of cells • Contain-1 or 2 protein coats (Capsids) • Contain a genetic material – either RNA or DNA • DO NOT reproduce or grow • ONLY function in a living cell (Host) • Can not metabolize • Can adapt or respond to environment (that is how viruses get stronger or more harmful) • May have a viral Envelope • Not given Latin names

  5. Virus structure Made up of 5 different parts: 1. Capsid (Head): Protein coat made of protein – made up of proteins called capsomeres 2. Contains nucleic acid inside of the capsid: DNA or RNA • Influenza (FLU) virus has DNA • Retrovirus (HIV) has RNA 3. Envelope or Body: outer lipid layer and an inner protein layer surrounding the capsid. • Two different shapes 4. Projections or Tail: 6 tail fibers that help it bind to the host cell 5. binding proteins: allow the virus to attach to the host cell

  6. What makes a retrovirus different from all other organisms we study? • Retroviruses is a virus that contains an RNA core as it’s genetic material that replicates by transcribing it’s RNA into DNA. The DNA is then incorporated into the host’s genome • Retro means= reverse order or backwards • Retroviruses have an enzyme called reverse transcriptase which makes RNA transcribe DNA • Normal Cell: DNA RNA • Retrovirus RNA (template strand) DNA

  7. RETROVIRUSES • Most complicated • Genetic information flows in the reverse direction • Have the enzyme reverse transcriptase • Transcribes DNA from an RNA template • The newly made DNA than integrates as a provirus into the nucleus of the animal cell • The host’s RNA polymerase transcribes the virual DNA into RNA molecules.

  8. Example of viruses • smallpox • the common cold • chickenpox • influenza • shingles • herpes • polio • Rabies, • Ebola • AIDS

  9. Different Types of Viruses • ADENOVIRUS • Respiratory infections; colds

  10. Polio

  11. Influenza Virus • Virus that causes the flu

  12. Small Pox

  13. TMV

  14. Viruses are classified by: • type of host cell • presence of DNA or RNA (retroviruses) • shape: Binal Polyhedral Filo

More Related