Chapter 18 Study GuideViruses & BacteriaLearning objectives- To become familiar with the overall genetics of viruses and bacteriao Viruses Single Stranded or Double Stranded DNA or RNA Smallest amount of genes is 4- Largest is several Hundred Capsid: Shell that encloses the genome is the CAPSID May have viral envelope that can help infect the host o Bacteria Unicellular Prokaryotic Can reproduce independently - Gram Positiveo Plasma membrane surrounded by cell wallo Stain purple- Gram Negativeo Plasma membrane surrounded by cell wall with twocomponents: Thin gelatinous layer made of petidoglycans An outer phospholipid layer with toxins that can cause diseaseo Stain pink o 2 layer cell wall Prevents many drugs from penetratingo Easily builds resistance to antibiotics- Know the various infection patterns of different types of viruseso Life Cycle of Phages Lytic Cycle - Phage injects DNA into cytoplasm - Phage DNA directs the synthesis of many new phages - Cell lyses and releases the new phages - New phages can bind to bacterial cells Lysogenic Cycle - Phage injects DNA into cytoplasm- Phage DNA integrates into host chromosome - Prophage DNA is copied when cell divides- On rare occasions a prophage may be excised from the hostchromosome o Life Cycle of Phages Virus contains RNA, capsid, and envelope of glycoproteins - Virus attaches to host cell- Virus enters cell via endocytosis- RNA exits virus- The viruses RNA is replicated o Life Cycle of Retrovirus - To learn how to compare viruses and bacteriaChapter 18 Study Guide- To learn about different types of viruses and bacteria and the diseases they causeo Viruses HIV: Human Immunodeficiency Virus - Causes AIDS: Acquired Immunodeficiency Syndrome - Attacks helper T cells and macrophageso Body’s defense against disease - Kills people indirectly by making them susceptible to…o Pneumonia o Fungal infectionso Unusual types of cancer SARS: severe acute respiratory syndrome - Caused by a coronavirus o Single-strandedo RNA- Atypical from pneumonia, or inflammation of the lungso Day of two of high fevero Dry Coughing o Low oxygen levels in blood- No cure known - Out break in southern Chinese provinceo Spread to Hong Kong Then to 30 other countrieso Jumped from wild animals sold at the local meat market to humanso Not easily transmitted from human to human Transmitted by direct droplets from infected persons cough or sneeze Ebola- Caused by filamentous virus o Single stranded o RNAo Enveloped - Outbreak in 1979o Central Africa - Transmission is by direct contact with…o Infected bloodo Body fluids o Organso Sexual activity- Causes hemorrhagic fever- hemorrhagic rash appears all over bodyo Fevero Vomitingo Diarrhea o Muscle weaknesso Massive bleeding Internal and externalo Circulatory system collapseChapter 18 Study Guideo Limited kidney and liver functions - Symptoms appear 2-21 days after the infection- Death rates rage form 50%-90%- No known cure or treatment- Limited to parts of Africa Hantavirus: Hantavirus Pulmonary Syndrome (HPS)o Single Stranded o RNAo Envelope - Normally infects deer mice- Outbreak in 1993o Southwestern U.S. - Dozens infectedo 50% died- As of Nov. 2003…o 353 cases reported in U.S. 30% died- Transmission by direct exposer to infected mouseo Breathing dust have cleaning rodent droppings o Disturbing Nestso Living/Working in rodent infested area - Symptoms start 1-3 weeks after exposureo Fevero Severe muscle aches Thighs Hips Back Shoulderso Respiratory distress Often severe or fatal - Death Rates range form 40%-50%- No known cure or treatment1. Be able to list distinguishing characteristics about viruses.a. Also know their structurei. Capsidii. Capsomeresiii. Can have either a DNA/RNA genome and single- or double-strandediv. Membrane envelope2. Know what a bacteriophage isa. Life cycle of phagesi. Compare and contrast lytic (virulent) and lysogenic (temperate) cycles3. Be able to explain the mechanism of infection for:a. What are the main differences in mechanisms of infection between a general DNA virus, an RNA virus, an enveloped virus, and a retrovirus?4. Know examples of different tissues/organ systems of the body that viruses can affectChapter 18 Study Guide5. Know the following viruses, what type of virus they are, how they are transmitted,their effects (symptoms or otherwise), and if it’s treatable. (I may give you a scenario—symptoms and other characteristics—of someone infected with this virus, and you should be able to pick out the virus from a list.) a. HIVi. Be familiar with the T-Cell count vs. time graphb. SARSc. Ebolad. Hantavirus e. Avian & H1N1 Influenza Virus6. Be able to list distinguishing characteristics of bacteriaa. Compare and contrast viruses and bacteria7. Know the following bacterial infections, what bacterium causes them (know scientific names), how they are transmitted, their effects (symptoms or otherwise),and if it is treatable. (I may give you a scenario—symptoms and other characteristics—of someone infected with a particular bacterium, and you should be able to pick out the virus from a list.)a. Botulismb. Anthraxc. MRSAd. Tetanuse. Lyme diseasef. Rocky Mountain Spotted FeverNOTE: Know all figures associated with this
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