Bell Work: Set up Cornell Notes Pg. 65 Title: Virus Structure Date 2/3/2016 EQ: How are viruses put together and how do they differ from cells? End

No longer accepted: Cladogram HW Shark WS Fungi WS Taxonomy WS Turn in for 70: Kingdom Sort Due Tomorrow: Virus Drawing

Today’s Standard (B.4C): compare the structures of viruses to cells, describe viral reproduction, and describe the role of viruses in causing diseases such as HIV and influenza. Essential Question: How are viruses put together, and how do they differ from cells?

First, some 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)

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. Standard: “Compare virus Structures to cells”

Viral Size

Basic Viral Components All viruses have… – Genetic material (just like cells!) DNA or RNA Makes up the core – Capsid (protein coat) Made of proteins Surrounds the core

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

Basic Viral Components Some viruses also have… – Viral Envelope Made of lipids (like cell membranes!) Surrounds the capsid ONLY ON SOME VIRUSES – Spikes Made of glycoproteins Used to attach to cells ONLY ON VIRUSES WITH ENVELOPES

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

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Specificity : viruses are very specific to the type of cells they infect 1) plant viruses infect plant cells 2) animal viruses infect only certain related species of animals 3) bacterial viruses (bacteriophages) infect only certain types of bacteria

Characteristics of Life Responds to the environment Evolutionary adaptation Has order (made of cells) Grows and develops Processes energy (require nutrients) Reproduces Maintains homeostasis

Viruses are NOT alive because they DO NOT have ALL of the characteristics of life.

Remember they are not this similar in size!

Assignment You will draw a virus on you paper, which must show DNA or RNA, a capsid, viral envelope, and spikes. Use a key to color code the image Compare and contrast a virus to a cell

Example Spike- Used to_______ Capsid-Made of______ Envelope- Made of ______ DNA- Genetic material Virus are like cells because…… Viruses differ from cells because….