2. BELL WORK(Buff Binder): Explain the difference between a PROKARYOTE and a EUKARYOTE. Also, take out your homework so I can check it!

3. Set up today’s page in your journal… Page: 59 Date: 2-4-15 Title: Viral Structure Essential Question: How does the structure of a virus compare to a cell? YES - Cornell notes, please!

4. OVERVIEW

5. Vocabulary Virus: a non-cellular (or acellular) pathogen Pathogen: any disease-causing agent Virology: the study of viruses Virion: a viral particle (piece of a virus)

6. Cellular Organisms vs Acellular Particles Eukaryotic Nucleus Prokaryotic Cell Virus Eukaryotic Cell 1 ųm (1000 nm) A virus’s size helps it to reproduce. We’ll talk about this tomorrow. If a cell was the size of our classroom, then an average virus would be the size of a softball.

7. Viral Size

8. Viral components – Capsid (protein coat) Made of proteins Surrounds the core – Genetic material DNA or RNA Inside the capsid – Envelope Made of lipids (like cell membranes!) ONLY ON SOME VIRUSES – Spikes Made of proteins Used to attach to cells ONLY ON VIRUSES WITH ENVELOPES 7

9. Generalized Structure of Viruses virions having envelopes = enveloped viruses virions lacking envelopes = naked viruses

10. Generalized Structure of Viruses 9

11. Helical Capsids Helical capsids are rod- like structures with the RNA in the center of the helix. A helix is made by stacking repeating units in a spiral. RNA protein coat

12. Tobacco Mosaic Virus Tobacco Mosaic Virus (TMV) is an example of a virus with a helical structure. Protein subunits wrap around the spiraling RNA strand. This image taken using an Electron Microscope

13. Adenovirus Adenoviruses cause diseases like pink-eye or the common cold

14. Bacteriophage Bacteriophage is a virus that infects bacteria.

15. 14

17. Specificity : viruses are highly specific to the cells they infect Examples: 1) plant viruses infect plant cells 2) animal viruses infect only certain related species of animals 3) bacterial viruses (bacteriophage) infect only certain types of bacteria. So, what about zombies?

18. For the rest of today… Complete your HIV handout from yesterday. Turn in your packet when you finish.