BIOL 1453 1st Edition Lecture 9Outline of Last LectureI. Nucleotide monomersII. DNA and RNA are polymers of nucleotides III. DNA is a double-stranded helixIV. REPLICATIONV. The flow of genetic information VI. From DNA to protein VII.TRANSCRIPTIONVIII.Eukaryotic RNA is processed before leaving the nucleus IX. TRANSLATIONX. The genetic code XI. REVIEWXII.Mutations can change the meaning of genesOutline of Current LectureI. Viruses and genetic material II. The lytic cycleIII. The lysogenic cycleIV. Phage reproductive cycles V. Viruses and diseaseVI. Emerging viruses VII.AIDS: a “retrovirus”VIII.To clone or not to clone?IX. DifferentiationX. DNA packingXI. Animal CloningXII.CloningXIII.Stem cells have medical potentialCurrent LectureI. Viruses and geneticmaterial a. Viral DNA maybecome part ofthe hostchromosome. b. Viruses aregenes packagedin protein. a phage ->HeadDNATailTail fiber300,000II. The lytic cycle a. When phage DNA enters alytic cycle (lytic= break orburst) inside a bacterium,it is replicated,transcribed, andtranslated. b. The new viral DNA andprotein molecules thenassemble into newphages, which burstfrom the host cell. i. bacteriophageIII. The lysogenic cycle a. In the lysogenic cycle, phage DNA inserts into the hostchromosome 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 cycle1. it can remain in the cell without causing a changein 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 cycleIV. Phage reproductive cyclesV. Viruses and disease a. Many viruses cause disease when they invade animal or plantcells. 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% ofAmericans. ii. “Herpes simplex 2” - genital herpes - infects ~20% ofAmericans. 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 300,000,000people. ii. WWI = 21m deaths in 4yrs; Great Swine Flu = same in 4monthsiii.AIDS kills 6000 people a day in Africa. (has increased dramatically)iv. Ebola has only killed 1600 people … but where is ithiding?(causes hemorrhagic fever)(50-90% mortalityrate) d. Many viruses have RNA as their genetic material. e. Most plant viruses have RNA genomes and enter throughwounds. i. three ways plant viruses spread 1. contaminated garden tools 2. insects 3. wind or other natural trauma that breaks andmoves the plant f. Some latent viruses steal a bit of host cell membrane as aprotective envelope. i. called envelope viruses ii. exits the cell without lysing the cell Membranous envelopeRNAProteincoatGlycoprotein spikeg. You have to wear universal barriers when working with apatient (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 changeover time) iii.on average more than 200,000 arehospitalized (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 virusbut don’t get rid of it completely i. second leading cause is herpetic viruses i. Herpes simplex 1 and 2 ii. the vericella-zoster virus (causes chicken pox andshingles) iii.Epstein–Barr virus has been indicated in mono (also burkitt’s lymphoma and chronic fatigue syndrome)iv. cytomegalovirus the most important of thecongenital viral infections (inherited from parents) v. human herpes virus 6 and 7 are associated with severalrashes vi.human herpes virus 8 causes Kaposi’s sarcoma (mostcommonly AIDS patients) VI. Emerging virusesa. Emerging viruses: new or newly studied (a majorconcern) i. RNA mutates faster than DNA (mostare RNA)ii. Changing host speciesiii.Globalization (the problem of bringing viruses from other countriesiv. VirusesH5N11. Ebola2. H5N1Ebolaa. Bird flu (AKA avian flu)b. H5N1 refers to the different types of the virus3. Coronavirusa. A family of virus, one of whichcauses SARSb. SARS- severe acute respiratorysystemb. Bird flu articleCoronavirusi. H5N1 is highly pathogenic to birds ii. it is endemic (meaning it occurs regularly in a specificpopulation 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 humansiv. Panzootic - it affect animals of many species over a widearea v. there is no evidence of efficient human to humantransmission (or airborne transmission) 1. almost all the cases were physical contact withinfected birds vi.60% mortality rate vii.Pandemic - An epidemic of the influenza virus thatspread on the world wide scale affecting a large portion of humansviii.high Lethality (high kill rate)ix.extremely variant (virulence - the ability of any microbeto 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 RNAtemplet) 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 whenthe viral DNAattaches to thenuclear 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 byasexual 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