1 / 18

Bacteria & Viruses

Bacteria & Viruses. Prokaryote Review. Mostly single-celled No nucleus or organelles Cell walls Reproduce mostly asexually Anaerobic or aerobic Heterotrophic or autotrophic. Bacteria are named by shape. Rod: bacillus Spheres: coccus Spirals: spirillum. Arrangement. Paired: diplo

gordon
Download Presentation

Bacteria & Viruses

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. Bacteria & Viruses

  2. Prokaryote Review • Mostly single-celled • No nucleus or organelles • Cell walls • Reproduce mostly asexually • Anaerobic or aerobic • Heterotrophic or autotrophic

  3. Bacteria are named by shape • Rod: bacillus • Spheres: coccus • Spirals: spirillum

  4. Arrangement • Paired: diplo • Grape-like clusters: staphylo • Chains: strepto

  5. Examples • Streptococcus: chains of spheres • Staphylospirillum: Grapelike clusters of spirals • Streptobacillus: Chains of rods

  6. Reproduction of Bacteria • The time of reproduction depends on how desirable the conditions are • Bacteria can rapidly reproduce themselves in warm, dark, and moist conditions • Some can reproduce every 20 minutes • (one bacterium could be an ancestor to one million bacteria in six hours)

  7. Bacteria Survival – Food sources • parasites – bacteria that feed on living things • saprophytes – use dead materials for food (exclusively) • decomposers – get food from breaking down dead matter into simple chemicals • important- because they send minerals and other materials back into the soil so other organisms can use them

  8. Helpful Bacteria • Decomposers help recycle nutrients into the soil for other organisms to grow • Bacteria grow in the stomach of a cow to break down grass and hay • Most are used to make antibiotics • Some bacteria help make insulin • Used to make industrial chemicals

  9. If I were a virus how big would bacteria be?

  10. Viruses Dead or alive?

  11. Viral structure • Viruses are not cells. • Basic structure: • Protein coat • Nucleic acid core (RNA or DNA) • Lipoprotein coat • (second coat – only in enveloped viruses)

  12. Virus Categories • DNA viruses – stable, do not mutate rapidly • Single-stranded or double-stranded • Smallpox, Hepatitis B • RNA viruses – mutate rapidly, unstable • Single-stranded or double-stranded • HIV, Rhinovirus

  13. Are viruses alive? • Only 1 characteristic of life: reproduction • Can only reproduce inside a host cell! • Process or reproduction = lytic cycle

  14. Lytic Cycle • Virus attaches to host cell’s membrane and injects its nucleic acid into the host cell. • The viral nucleic acid takes over protein synthesis, creating new viruses. • The host cell bursts, lyses, releasing the newly formed viruses.

  15. Before attachment Attachment Injection Release Assembly Replication

  16. HIV undermines the body's ability to protect against disease by depleting T cells thus destroying the immune system. • The virus can infect 10 billion cells a day, yet only 1.8 billion can be replaced daily.

  17. After many years of a constant battle, the body has insufficient numbers of T-Cells to mount an immune response against infections. At the point when the body is unable to fight off infections, a person is said to have the disease AIDS. • It is not the virus or the disease that ultimately kills a person; it is the inability to fight off something as minor as the common cold.

More Related