Go to Section: Under the Microscope Microorganisms are living things that can only be seen through a microscope. Imagine that you have just discovered a new microorganism. The first thing that you want to do is to tell the scientific community all about your new discovery. Section 19-1 Interest Grabber

Go to Section: 1.Describe your microorganism in detail. 2.Describe its habitat. 3.Classify your microorganism by giving it a genus and species based on its characteristics. Section 19-1 Interest Grabber continued

Go to Section: 19–1Bacteria A.Classifying Prokaryotes 1.Eubacteria 2.Archaebacteria B.Identifying Prokaryotes 1.Shapes 2.Cell Walls 3.Movement C.Metabolic Diversity 1.Heterotrophs 2.Autotrophs 3.Releasing Energy Section 19-1 Section Outline D.Growth and Reproduction 1.Binary Fission 2.Conjugation 3.Spore Formation E.Importance of Bacteria 1.Decomposers 2.Nitrogen Fixers 3.Human Uses of Bacteria

Go to Section: Section 19-1 Concept Map are classified into the kingdoms of live in harsh environments such as include a variety of lifestyles such as Bacteria EubacteriaArchaebacteria Infecting large organisms Thick mudLiving in soil Animal digestive tracts Salty lakesHot springs

Go to Section: Peptidoglycan Cell wall Cell membrane Ribosome Flagellum DNA Pili Section 19-1 The Structure of a Eubacterium

Go to Section: What Viruses Mean to You If you have ever had a cold, you are probably familiar with the word virus. It is a word that makes most people frown. Section 19-2 Interest Grabber 1.What do you think of when you hear the word virus? Make a list of all the words you can think of that relate to viruses. 2. What are two things that you would like to find out about viruses?

Go to Section: 19–2Viruses A.What Is a Virus? B.Viral Infection 1.Lytic Infection 2.Lysogenic Infection C.Retroviruses D.Viruses and Living Cells Section 19-2 Section Outline

Go to Section: T4 Bacteriophage Tobacco Mosaic Virus Influenza Virus Head Tail sheath DNA Tail fiber RNA Capsid Surface proteins Membrane envelope RNA Capsid proteins Section 19-2 Figure 19-9 Virus Structures

Go to Section: Figure Lytic and Lysogenic Infections

Go to Section: Section 19-2 Figure Viruses and Cells

Go to Section: Bacteria vs. Humans Bacteria are all around you—in the air you breathe, under your feet, on your skin, and even in your body! They may be tiny, but they can still have an impact on your life. Use what you already know about bacteria to answer these questions. Section 19-3 Interest Grabber

Go to Section: 1.In what ways are bacteria similar to humans? 2.In what ways are bacteria different from humans? 3.How can bacteria be harmful? Section 19-3 Interest Grabber continued

Go to Section: Section 19-3 Section Outline 19–3Diseases Caused by Bacteria and Viruses A.Bacterial Disease in Humans 1.Using Cells for Food 2.Releasing Toxins 3.Preventing Bacterial Disease B.Bacterial Disease in Animals C.Controlling Bacteria 1.Sterilization by Heat 2.Disinfectants 3.Food Storage and Processing D.Viral Disease in Humans E.Viral Disease in Animals F.Viral Disease in Plants G.Viroids and Prions 1.Viroids 2.Prions

Go to Section: Tooth decay Lyme disease Tetanus Tuberculosis Salmonella food poisoning Pneumonia Cholera Streptococcus mutans Borrelia burgdorferi Clostridium tetani Mycobacterium tuberculosis Salmonella enteritidis Streptococcus pneumoniae Vibrio cholerae Regular dental hygiene Protection from tick bites Current tetanus vaccination Vaccination Proper food-handling practices Maintaining good health Clean water supplies DiseasePathogenPrevention Section 19-3 Common Diseases Caused by Bacteria

Go to Section: Oncogenic viruses Retrovirus Adenoviruses Herpesviruses Poxviruses DNA RNA DNA Cancer Cancer, AIDS Respiratory infections Chickenpox Smallpox Type of VirusNucleic AcidDisease Section 19-3 Common Diseases Caused by Viruses

Video Click the image to play the video segment. Video Lytic and Lysogenic Cycles

Internet The latest discoveries in microorganisms and viruses Links from the authors on smallpox vaccinations Career links on epidemiologists Interactive test Articles on bacteria and viruses For links on bacteria, go to and enter the Web Code as follows: cbn For links on the lytic cycle, go to and enter Web Code as follows: cbn Go Online

Section 1 Answers Interest Grabber Answers 1.Describe your microorganism in detail. Students should describe the appearance of their imaginary organism. A possible answer might include its color and shape. 2.Describe its habitat. Students should describe whether it lives in water, soil, or another organism; if it is a plant or animal; and how it gets its energy. 3.Classify your microorganism by giving it a genus and species based on its characteristics. Students should specify a name for their organism.

Section 2 Answers Interest Grabber Answers 1.What do you think of when you hear the word virus? Make a list of all the words you can think of that relate to viruses. Possible answers: disease, sickness, AIDS virus, infection, microscopic, vaccines, flu, cold 2.What are two things that you would like to find out about viruses? Possible answers: How are viruses related to bacteria? How do viruses cause disease? How do viruses reproduce? How do viruses spread from person to person?

Section 3 Answers Interest Grabber Answers 1.In what ways are bacteria similar to humans? Like humans, bacteria are alive, and some can move. Both obtain energy, exchange gases, grow, and reproduce. 2.In what ways are bacteria different from humans? Unlike humans, bacteria are extremely small; some can live in harsher environments and without oxygen; some bacteria use sunlight to produce their own food. 3.How can bacteria be harmful? Bacteria cause diseases, release poisonous chemicals, and compete with humans for food.

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