BIOL 1453 1st Edition Lecture 9 Outline of Last Lecture I Nucleotide monomers II DNA and RNA are polymers of nucleotides III DNA is a doublestranded helix IV REPLICATION V The flow of genetic information VI From DNA to protein VII TRANSCRIPTION VIII Eukaryotic RNA is processed before leaving the nucleus IX TRANSLATION X The genetic code XI REVIEW XII Mutations can change the meaning of genes Outline of Current Lecture I Viruses and genetic material II The lytic cycle III The lysogenic cycle IV Phage reproductive cycles V Viruses and disease VI Emerging viruses VII AIDS a retrovirus VIII To clone or not to clone IX Differentiation X DNA packing XI Animal Cloning XII Cloning XIII Stem cells have medical potential Current Lecture I Viruses and material genetic a Viral DNA may become part of the host chromosome b Viruses are genes packaged in protein a phage Head DNA Tail Tail fiber 300 000 II The lytic cycle a When phage DNA enters a lytic cycle lytic break or burst inside a bacterium it is replicated transcribed and translated b The new viral DNA and protein molecules then assemble into new phages which burst from the host cell i bacteriophage III The lysogenic cycle a In the lysogenic cycle phage DNA inserts into the host chromosome and is passed on to generations of daughter cells i Much later it may initiate phage production ii prophage is created when phage DNA iii Three possibilities for this cycle 1 it can remain in the cell without causing a change in the cell Asymptomatically changes the cell 2 The bacteria starts behaving in a different matter changes the function 3 It can convert to the lytic cycle IV Phage reproductive cycles V Viruses and disease a Many viruses cause disease when they invade animal or plant cells b Some viruses can enter a cell and remain dormant latent for long periods of time with no effects stress and certain foods can cause a flare up i Herpes simplex 1 cold sore virus infects 75 of Americans ii Herpes simplex 2 genital herpes infects 20 of Americans iii HIV is also a latent virus 1 HIV is the causative virus to AIDS c Others are immediately or intermittently harmful i In the 1900s alone smallpox killed at least 300 000 000 people ii WWI 21m deaths in 4yrs Great Swine Flu same in 4 months iii AIDS kills 6000 people a day in Africa has increased dramatically iv Ebola has only killed 1600 people but where is it hiding causes hemorrhagic fever 50 90 mortality rate d Many viruses have RNA as their genetic material e Most plant viruses have RNA genomes and enter through wounds i three ways plant viruses spread 1 contaminated garden tools 2 insects 3 wind or other natural trauma that breaks and moves the plant f Some latent viruses steal a bit of host cell membrane as a protective envelope i called envelope viruses ii exits the cell without lysing the cell Membranous envelope RNA Protein coat Glycoprotein spike g You have to wear universal barriers when working with a patient for all procedures that draw bodily fluids h The leading cause of human viral disease is the flu i type a and type b ii antigenic drift its genetic makeup will slightly change over time iii on average more than 200 000 are hospitalized 36 000 die iv three main steps to fight it 1 get the flu vaccine 2 take everyday preventive actions wash hands warm water and cover mouth when sneeze and avoid touching your eyes nose or mouth 3 take anti flu viral drugs if your doctor writes you a prescription antibiotics to nothing against the flu antiviral drugs are used to treat the flu not used to prevent the flu antiviral medications are not a substitute for the vaccination v most antiviral drugs inhibit the reproduction of the virus but don t get rid of it completely i second leading cause is herpetic viruses i Herpes simplex 1 and 2 ii the vericella zoster shingles virus causes chicken pox and iii Epstein Barr virus has been indicated in mono also burkitt s lymphoma and chronic fatigue syndrome iv cytomegalovirus the most important of the congenital viral infections inherited from parents v human herpes virus 6 and 7 are associated with several rashes vi human herpes virus 8 causes Kaposi s sarcoma most commonly AIDS patients VI Emerging viruses a Emerging viruses new or newly studied a major concern i RNA mutates faster than DNA most are RNA ii Changing host species iii Globalization the problem of bringing viruses from other countries iv Viruses H5N 1 1 Ebola 2 H5N1 Ebola a Bird flu AKA avian flu b H5N1 refers to the different types of the virus 3 Coronavirus a A family of virus one of which causes SARS b SARS severe acute respiratory system b Bird flu article Coronavir us i H5N1 is highly pathogenic to birds ii it is endemic meaning it occurs regularly in a specific population or area in many bird populations iii Epizootic an epidemic a diseases that appears in a given population during a given period at a rate that exceeds what is was expected in non humans iv Panzootic it affect animals of many species over a wide area v there is no evidence of efficient human to human transmission or airborne transmission 1 almost all the cases were physical contact with infected birds vi 60 mortality rate vii Pandemic An epidemic of the influenza virus that spread on the world wide scale affecting a large portion of humans viii high Lethality high kill rate ix extremely variant virulence the ability of any microbe to cause disease VII AIDS a retrovirus a The AIDS virus HIV makes DNA on an RNA template backwards i it is a retro virus any virus that makes DNA on a RNA templet b Inside a cell HIV uses its RNA as a template for making DNA Then DNA is inserted into a host chromosome i called provirus when the viral DNA attaches to the nuclear DNA ii exits the host cell without lysing the cell HIV is an envelope virus VIII To clone or not to clone a A clone is an individual created by asexual reproduction and thus is genetically identical to a single parent b Cloning has many benefits but evokes just as many concerns c Banting is an endangered species of cow that has been cloned IX Differentiation a Differentiation the process in which cells specialize in a specific type and function yields a variety of cell types each expressing a different combination of genes i In multicellular eukaryotes cells become specialized as a zygote fertilized female egg develops into a mature organism ii Different types of cells make different proteins because different combinations of genes are active in each type b