Chapter 18 Study Guide Viruses Bacteria Learning objectives To become familiar with the overall genetics of viruses and bacteria o 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 Positive o Plasma membrane surrounded by cell wall o Stain purple Gram Negative o Plasma membrane surrounded by cell wall with two components Thin gelatinous layer made of petidoglycans An outer phospholipid layer with toxins that can cause disease o Stain pink o 2 layer cell wall Prevents many drugs from penetrating o Easily builds resistance to antibiotics Know the various infection patterns of different types of viruses o 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 host chromosome 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 bacteria Chapter 18 Study Guide To learn about different types of viruses and bacteria and the diseases they cause o Viruses HIV Human Immunodeficiency Virus Causes AIDS Acquired Immunodeficiency Syndrome Attacks helper T cells and macrophages o Body s defense against disease Kills people indirectly by making them susceptible to o Pneumonia o Fungal infections o Unusual types of cancer SARS severe acute respiratory syndrome Caused by a coronavirus o Single stranded o RNA Atypical from pneumonia or inflammation of the lungs o Day of two of high fever o Dry Coughing o Low oxygen levels in blood No cure known Out break in southern Chinese province o Spread to Hong Kong Then to 30 other countries o Jumped from wild animals sold at the local meat market to humans o 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 RNA o Enveloped Outbreak in 1979 o Central Africa Transmission is by direct contact with o Infected blood o Body fluids o Organs o Sexual activity Causes hemorrhagic fever hemorrhagic rash appears all over body o Fever o Vomiting o Diarrhea o Muscle weakness o Massive bleeding Internal and external o Circulatory system collapse Chapter 18 Study Guide o 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 RNA o Envelope Normally infects deer mice Outbreak in 1993 o Southwestern U S Dozens infected o 50 died As of Nov 2003 o 353 cases reported in U S 30 died Transmission by direct exposer to infected mouse o Breathing dust have cleaning rodent droppings o Disturbing Nests o Living Working in rodent infested area Symptoms start 1 3 weeks after exposure o Fever o Severe muscle aches Thighs Hips Back Shoulders o Respiratory distress Often severe or fatal Death Rates range form 40 50 No known cure or treatment 1 Be able to list distinguishing characteristics about viruses a Also know their structure i Capsid ii Capsomeres iii Can have either a DNA RNA genome and single or doublestranded iv Membrane envelope 2 Know what a bacteriophage is a Life cycle of phages i Compare and contrast lytic virulent and lysogenic temperate cycles 3 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 affect Chapter 18 Study Guide 5 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 HIV i Be familiar with the T Cell count vs time graph b SARS c Ebola d Hantavirus e Avian H1N1 Influenza Virus 6 Be able to list distinguishing characteristics of bacteria a Compare and contrast viruses and bacteria 7 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 Botulism b Anthrax c MRSA d Tetanus e Lyme disease f Rocky Mountain Spotted Fever NOTE Know all figures associated with this lecture