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Chapter 18 Blog: Genetics of Viruses and Bacteria (Ambika)

Page history last edited by Ambika Sharma 13 years, 6 months ago

In the first section of this page, you will write a daily summary of that day's class.  For example in  your chapter 2 blog, your first entry should be titled 9/3/10.  You should then write a one or two paragraph summary of that day's lecture, outlining the major points.  In the second section, you are required to add two items (link to a website, video, animation, student-created slide show, student-created PowerPoint presentation) and one journal article pertaining to a topic in this chapter.  A one-paragraph summary must accompany each item describing the main idea and how it applies to the lecture topic.  Please see the PBWorks help guide for assistance embedding video and other items directly in the page.  I will also produce a how-to video on using tables to wrap text around items and other useful tips.  Please see the syllabus for organization and grading details.

 

A.  Daily Blog

 

     Chapter 18 focuses on, as you can probably already tell from title, the genetics of viruses and bacteria! So...what is a virus? A virus is a small, nonliving particle that consists of nucleic acid enclosed in a protein coat. I'm sure you are wondering, why and how are viruses nonliving? Well, viruses do not use energy and they are not composed of cells. Over 4,000 different types of viruses have been idtentified and studied. Viruses do share similarities but they are greatly varied when it comes to characteristics, such as host range and structure. The host range is the number of species a virus can infect. What are features that are common to all viruses? Simple! A capsid (protein coat that surrounds the viruses' genome), a viral envelope (which encloses the capsid) and, of course, all viruses have either DNA or RNA. There are some special viruses, however, who have terminal knobs that are composed of glycoproteins. These oh so special viruses are known as bacteriophages, they anchor host cell so the virus can transfer it's genetic material into the cell. Let's now look at the six step process on how viruses replicate:

     1) Attachment of the virus to the host cell

     2) Entry of the viral genome into the host cell

     3) Integration, the viral genome is inserted into the hot cell genome by an enzyme called integrase

     4) Synthesis of viral components, the viral genome is transcribed and translated

     5) Viral assembly, the components are put together and the virus is recreated

     6) Release of the created viruses, by either lysing the cell or exiting using exosytosis.

 

     Now let's cover plasmids. What are plasmids? Plasmids are tiny circular pieces of DNA which are found in bacteria. There are many different kinds of plasmids, some include: resistance plasmids (resist antibiotics and toxins), degradative plasmids (carry genes that allow bacteria to digest substance), col-plasmids (encode for colicins- proteins that kill bacteria), virulence plasmids (carry genes that make bacteria pathogenic strains) and fertility plasmids (allow bacteria to mate ;D)

 

 

 

B.  Useful Materials

 

Useful Video

 

Here is a video I found! It is an animation of a virus attack. It is quite cheesy and suspenseful so parent/guardian consent is recommended ;o) JUST KIDDING. I hope you enjoy the video. It really conveys the message that viruses affect the functions in our bodies.

 

Useful Image

 

          This image illustrates the lytic and lysogenic cycle. As it is clearly shown the viral DNA injects itself into the cell, the virus is introduced to the cell and either new viruses are assembled and the cell goes BOOM or the viral DNA integrates itself into the bacteria and continues to spread.

 

 

Useful Article

Hardenbergia

virus A....

http://www.ncbi.nlm.nih.gov/pubmed/21394605   This article discusses a virus, the Hardenbergia virus A, that is part of the family Betaflexiviridae, in a wild legume in Southwest Australia. This article uses a lot of termonology that we have started to pick up on in class. The predicted structure of the genome is the 5' untranslated region. The N-terminal region contains a replicase protein, while the C-terminal region has a coat protein. The way the genome is organized causes the Hardenbergia virus to be present within this wild legume.

 

 

 

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