Survey
* Your assessment is very important for improving the work of artificial intelligence, which forms the content of this project
Download virus_20 - San Jacinto Unified School District | Haiku Learning
Document related concepts
no text concepts found
Transcript
Virus Video http://www.youtube.com/watch?v=Rpj0emEGShQ Viruses & Bacteria can cause infection • Pathogen - Any disease-causing agent 1 nanometer (nm) = one billionth of a meter 100 nm eukaryotics cells 10,000-100,000 nm viruses 50-200 nm prokaryotics cells 200-10,000 nm viroids 5-150 nm prion 2-10 nm Virus • 2 basic parts: – protein coat. – Contains DNA or RNA • non-living pathogen • Viruses have a simple structure. enveloped (influenza) capsid helical (rabies) nucleic acid lipid envelope polyhedral (foot-and-mouth disease) Surface proteins capsid nucleic acid surface proteins lipid envelope surface proteins capsid nucleic acid All viruses have two main parts: 1. DNA or RNA – genetic info 2. Capsid – a protein coat Bacteriophages: viruses that infect bacteria. capsid DNA tail sheath tail fiber • Viruses enter cells in various ways. – bacteriophages pierce host cells colored SEM; magnifications: large photo 25,000; inset 38,000x Virus inserting it’s DNA into a bacterial cell. Viral Replication Picture http://glencoe.mcgrawhill.com/sites/9834092339/student_view0/chapter28/life_cycle _of_t2_phage.html http://www.mcgrawhill.ca/school/schoolGraphics /biology2_1.mpg • Viruses enter cells in various ways. – Endocytosis (pulled into cell) • Viruses enter cells in various ways. – fuse with membrane Viruses contain DNA/RNA, proteins, and they reproduce… Are viruses alive??? NO. They contain no nucleus, cytoplasm, organelles or cell membrane; they cannot carry out cell functions, and they can only “reproduce” when an infected cell builds new viruses. Grouping Viruses • Grouped according to: – Presence of Capsid and envelope – shape – RNA or DNA, single or double stranded – structure Viral Group Nucleic Acid Shape and Structure Example Papovaviruses DNA Icosahedral, non-env. Warts, cancer Adenoviruses DNA Icosahedral, non-env. Resp. & intestinal infections Herpesviruses DNA Icosahedral, enveloped Herpes simplex, chicken pox, mono, shingles Poxviruses DNA Complex brick, enveloped Small pox, cow pox Picornaviruses RNA Icosahedral, non-env. Polio, hepatitis, cancer Myxoviruses RNA Helical, enveloped Influenza A, B, C Rhabdoviruses RNA Helical, enveloped Rabies Retroviruses RNA Icosahedral, enveloped AIDS, cancer Treatment and Prevention Anti-viral drugs: interfere with viral DNA/RNA synthesis Vaccines – creates antibodies Inactivatedthe virus is “dead”; cannot replicate Attenuated- the virus has been genetically altered; still functional, but won’t cause disease Attenuated tend to be more effective vaccines Some Pictures are Graphic The Lysogenic Cycle When viruses remain inactive within host cells for days, months or years. •Viral DNA inserted directly into the host DNA. •Viral DNA copied with host DNA during replication •Viral DNA passed on to daughter cells during mitosis •Remains dormant (no viral proteins are produced) until some “triggering event” Examples: Chickenpox and Shingles; HIV Stress chemicals UV light ??? heat POXVIRUSES Small Pox BACK PICORNAVIRUSES - Polio BACK Destroys the motor neurons that are producing the virus. The result is a loss of muscle control including the diaphragm. The iron lung changes the pressure to pump air in and out of the lungs. U.S. President Franklin Delano Roosevelt MYXOVIRUSES Flu Virus BACK RHABDOVIRUSES Rabies BACK RETROVIRUSES Herpes HPV Tree man Ebola Syphilis • Sketch & Label the following: T4 Bacteriophages capsid DNA tail sheath tail fiber
Related documents