Presentation is loading. Please wait.

Presentation is loading. Please wait.

BACKNEXT BACKNEXT CONTENTS 1. Introduction 2. Virus Structure 3. Virus Replication 4. Virology 5. Virus and Medicine 6. Review Introduction – Structure.

Similar presentations


Presentation on theme: "BACKNEXT BACKNEXT CONTENTS 1. Introduction 2. Virus Structure 3. Virus Replication 4. Virology 5. Virus and Medicine 6. Review Introduction – Structure."— Presentation transcript:

1

2 BACKNEXT

3 BACKNEXT CONTENTS 1. Introduction 2. Virus Structure 3. Virus Replication 4. Virology 5. Virus and Medicine 6. Review Introduction – Structure – Replication – Virology – Medicine - Review

4 BACKNEXT We have all gotten viruses… from bacteria, plants to animals. Viruses cause colds, flu, warts and diseases such as measles, AIDS and cancer. AND not all viruses are harmful to humans. BUT not all viruses cause diseases, Introduction – Structure – Replication – Virology – Medicine - Review

5 BACKNEXT WHAT IS A VIRUS? Introduction – Structure – Replication – Virology – Medicine – Review

6 BACKNEXT Introduction – Structure – Replication – Virology – Medicine - Review A VIRUS is either DNA or RNA, that is protected by a protein coat called a CAPSID. DNACAPSID VIRUS

7 BACKNEXT Why are some viruses harmful? Introduction – Structure – Replication – Virology – Medicine - Review Virus invades cell Virus forces cell to make copies of virus Eventually so many copies are made, the cell explodes, releasing all of the new viruses When your cells make viruses instead of operating normally, YOU get sick

8 BACKNEXT DISEASEVIRUSES AIDSHIV Wart Herpes Simplex Virus FluInfluenza MeaslesMorbillivirus. CancerHepatitis B Introduction – Structure – Replication – Virology – Medicine - Review Examples of some viral diseases:

9 BACKNEXT Who do viruses infect? Viruses infect Bacteria –These viruses are called bacteriophages Viruses infect Plants –One example is the Tobacco Mosaic Virus Viruses infect Animals –One example is the common cold Viruses usually infect a specific host including: Introduction – Structure – Replication – Virology – Medicine - Review

10 BACKNEXT Lets look at the Defining Properties of Viruses Viruses are parasites that invade cells Viruses have either DNA (Deoxyribose Nucleic Acid) or RNA (Ribonucleic Acid) Viruses direct the synthesis of new virus within a host cell. Newly made viruses infect other cells. Introduction – Structure – Replication – Virology – Medicine - Review

11 BACKNEXT Cell Biology Let's review a little cell biology since viruses cannot multiply without the help of cells. The viruses enter the cell and forces the cell to make more viruses. The cell has three main zones: Introduction – Structure – Replication – Virology – Medicine - Review nucleus membrane cytoplasm Cytoplasm – this is the factory where biochemical reactions occur. Membrane – this double layer protects the cell and allows the cell to communicate with the outside environment. Nucleus – this holds the DNA or genetic information about the cell.

12 BACKNEXT DNA/RNA DNA, deoxyribonucleic acid, is the double-stranded molecule that encodes genetic information (e.g. your hair color, height, etc.) in the nucleus of cells. The complete set of DNA in a cell is called the genome. RNA, ribonucleic acid, is typically single stranded so that it can be read to make proteins. Introduction – Structure – Replication – Virology – Medicine - Review DNA or RNA code for genes that defines who we are.

13 BACKNEXT How small is a virus? Introduction – Structure – Replication – Virology – Medicine - Review

14 BACKNEXT If a cell was the size of your classroom, then an average virus would be the size of a softball. Viruses range in size from 20 nanometers (nm) – 250 nanometers (nm) 1 nm = inches m m m m m m 0 m viruses animal cells bacteria proteins atom Go five more feet!

15 BACKNEXT 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 Introduction – Structure – Replication – Virology – Medicine - Review

16 BACKNEXT 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. Introduction – Structure – Replication – Virology – Medicine - Review This image taken using an Electron Microscope

17 BACKNEXT Adenovirus Introduction – Structure – Replication – Virology – Medicine - Review Adenoviruses cause diseases like pink-eye or the common cold

18 BACKNEXT Bacteriophage Introduction – Structure – Replication – Virology – Medicine - Review Bacteriophage is a virus that infects bacteria.

19 BACKNEXT Enveloped Viruses Introduction – Structure – Replication – Virology – Medicine - Review Enveloped viruses are viruses which have a membrane coat surrounding the protein coat or capsid. These viruses are common in animal viruses, but are uncommon in plant viruses. Herpes Simplex Virus. A membrane (made of proteins) surrounds the capsid (also made of proteins) which surrounds the viral DNA.

20 BACKNEXT How do viruses replicate? Introduction – Structure – Replication – Virology – Medicine - Review

21 BACKNEXT Replication Phases V - Release -Assembly of virus DNA and protein coat into whole new viruses -Leaving the cell Phase I Phase II Phase IV Phase VPhase III Introduction – Structure – Replication – Virology – Medicine - Review I, II, III - Viruses enter cell -Attachment to cell membrane -Penetration inside cell -Losing virus protein coat IV - Replication -Tricks cell into making more viral DNA -Tricks cell into making viral protein coat

22 BACKNEXT The concept of a virus as an organism challenges the way we define life: *Viruses do not breathe. *Viruses do not metabolize. *Viruses do not grow. *However, they do reproduce. Introduction – Structure – Replication – Virology – Medicine - Review

23 BACKNEXT Are Viruses Living? Introduction – Structure – Replication – Virology – Medicine - Review Create a table where one column represent properties of living organisms and the second column represent properties of a virus. Properties of Living Organisms Properties of Viruses Breathes (respires)Doesnt breathe MetabolizesDoesnt metabolize GrowsDoesnt grow Reproduces

24 BACKNEXT A Brief History of Virology Introduction – Structure – Replication – Virology – Medicine - Review ~1400BC First written record of virus infections in heiroglyphics found in Memphis, Eygpt 100BC – China Protection from smallpox using variolation practice Vaccination Edward Jenner vaccinated a boy with cowpox-infected material 1880 – Germ Theory Robert Koch & Louis Pasteur Pasteur identified rabies to be cause by an agent he termed virus from the Latin for poison beginning of virology Dmitri Iwanowski showed that ceramic filtered extracts from diseased plants could transmit disease to other plants Martinus Beijerinick work on TMV Freidrich Loeffler & Paul Frosch work on foot-and-mouth disease in cattle 1909 Landsteiner & Popper Poliomyelitis (Yellow Fever) was the first human disease to be recognized as a viral disease Discoveries of Ebola, West Nile, HIV, SARS Bacteriophages (eaters of bacteria)Frederick Twort & Felix dHerelle discovered viruses which infect bacteria.

25 BACKNEXT Atomic Force Microscope – A tiny tip probes a surface, from which the shape of the surface can be determined X-ray Crytallography – X-rays are directed at a sample. How those rays scatter can be used to determine the structure of that sample Techniques to Study Viruses

26 BACKNEXT Filters – Very small holes in material filter only viruses through Sedimentary Centrifugation – A sample is spun so fast, different elements in it are separated by density Electron Microscope – Electrons are smaller than light wavelengths, so viruses can be seen by reflecting electrons off of them

27 BACKNEXT Viruses Can Help Cells, Too Introduction – Structure – Replication – Virology – Medicine - Review - Since viruses can transport DNA and RNA into cells, scientists are exploring Gene Therapy - In Gene Therapy, viral genetic material is replaced with new DNA - In time, this could be used to cure genetic diseases. Currently we have no cure for these types of illnesses

28 BACKNEXT The End! And Review Viruses are very simple: a shell containing either DNA or RNA. They infect by hijacking cells machinery to force them to make more viruses. Viruses are tiny, even compared to a cell. Some viruses may prove useful in gene therapy as natural carriers of DNA that was specially designed to be good for a particular reason. Introduction – Structure – Replication – Virology – Medicine - Review

29 BACKNEXT The End Introduction – Structure – Replication – Virology – Medicine - Review

30 BACKNEXT VIRUS A living thing that provides a source of energy for a virus or an organism Organisms that live on or near a host and cause it harm. A tiny, nonliving that invades and then multiplies inside of a cell. A virus that immediately goes into action. It begins to take over cell functions and produce the viruss proteins and genetic material.These parts then assemble into new viruses. The viruses multiply like a copy machine left on. When it is full it bursts open – releases the new viruses and dies. Some viruses hide for a while and become part of the cells genetic material. It may stay inactive and hidden for years. Then under certain conditions it becomes active and acts like an active virus. Ex – cold sores

31 BACKNEXT How Viruses Multiply Active viruses enter cells and immediately begin to multiply, leading to the quick death of the invaded cells. - Viruses

32 BACKNEXT How Viruses Multiply Hidden viruses hide for a while inside host cells before becoming active. - Viruses

33 BACKNEXT Active and Hidden Viruses Activity Click the Active Art button to open a browser window and access Active Art about active and hidden viruses. - Viruses

34 BACKNEXT Deadly Virus Click the Video button to watch a movie about deadly viruses. - Viruses

35 BACKNEXT Common Viral Diseases Unlike with bacterial diseases, there are currently no medications that can cure viral infections. - Viruses, Bacteria, and Your Health


Download ppt "BACKNEXT BACKNEXT CONTENTS 1. Introduction 2. Virus Structure 3. Virus Replication 4. Virology 5. Virus and Medicine 6. Review Introduction – Structure."

Similar presentations


Ads by Google