Unit 5: The Kingdoms of Life Module 12: Simple Organisms NC Essential Standard: 1.2.3 Explain how specific cell adaptations help cells survive in particular environments 2.1.2 Analyze how various organisms accomplish life functions What exactly is a germ? Germ is a commonly used term for tiny living organisms that make us sick! The correct term for organisms that cause disease is pathogen. Germs or pathogens may include living organisms such as bacteria, protists, or fungi. Germs also include viruses, although they are technically not alive! HOWEVER Not all tiny living organisms (microorganisms) are germs.there are MANY, MANY more helpful microorganisms than there are harmful ones! Name 2 reasons that viruses are not considered living things: 1. 2. I. Is a virus a living thing? A. Viruses, although due to the lack of cellular structure, are classified as microorganisms. B. Viruses are composed of a (called a capsid) that protects a - either DNA or RNA. The shape of the capsid determines the type of cell the virus can infect. C. A virus can only exist by infecting a. Viruses are classified by the reproductive cycle it uses to infect the host cell. 1. The lytic cycle describes the life cycle in which a virus uses the host cell to make copies of itself, then. 2. The lysogenic cycle describes the life cycle in which the virus has a in which the virus remains inactive within the cell. This dormant period may last for weeks, months, or years. An environmental trigger may cause the viral DNA to emerge from the host DNA and begin a lytic cycle of reproduction. 155
Using the diagram, explain how lytic and lysogenic are different: Identify 3 viral diseases: 1. 2. 3. Differentiate between active and passive immunity: http://images.encarta.msn.com/xrefmedia/aencmed/targets/illus/ilt/t012837a.gif D. Viruses are pathogenic, or microorganisms. 1. HIV causes AIDS. HIV infects, which are important for the immune response. Thus, people with AIDS often die of, such as pneumonia. 2. Several different viruses cause influenza (the flu ). Influenza viruses infect. The lysis of these cells leads to some of the typical symptoms of the flu, such as sore throat and congestion. 3. A poxvirus causes smallpox. Smallpox starts in the cells of the. Symptoms include severe headaches, muscle ache, and pustules on the skin. E. Virus Prevention and Treatment 1. Vaccines can be developed for viral diseases. A vaccine uses a to turn on the immune response so that antibodies are produced. a. Active immunity to a virus is conferred by a or by exposure to the virus itself. b. Passive immunity is conferred when are passed between individuals (ie. through breast milk). 2. Antiviral medications work by. Antibiotics are NOT effective against viruses! 156
Check Yourself! 1. What are the two parts of a virus? F. Viruses and Natural Selection 2. What are the two reproductive cycles of viruses? 3. What is a pathogen? 4. What type of cell does HIV infect? 5. Why is there a different flu virus each year? 1. Viruses often, meaning the actual virus being spread changes with each outbreak. 2. Mutations in the HIV virus make developing a treatment or vaccine difficult. Viruses that are resistant due to mutations can survive and reproduce by. 3. Flu are caused by viruses that are genetically different enough from earlier years viruses that people have little immunity to them. Identify 3 ways that bacteria are beneficial: 1. 2. 3. II. Are all bacteria bad? A. All bacteria are classified in the kingdoms Eubacteria and Archaebacteria. They are differentiated by the chemicals found in the bacterial cell wall. They are all. B. Bacteria through binary fission, but can also exchange DNA by conjugation. This allows for. C. The vast majority of bacteria in our world are. They are important and perform many other ecosystem services. They exist in the intestines of some animals and aid digestion. They are also important in. D. Some bacteria are. One example is the bacterium Mycobacterium tuberculosis, which causes tuberculosis. The disease attacks the lungs and causes coughing, chest pain, fatigue and fever it can be fatal if not treated. This bacterium causes disease because it. The cells are broken down by the 157
bacteria as a source of nutrition. Other bacteria harm the host by releasing toxins such the bacterium that causes food poisoning. E. Pathogenic bacteria can be treated with antibiotics. Antibiotics kill the bacteria by. Bacteria that are resistant to antibiotics can survive and reproduce by natural selection. This means that new antibiotics must continually be developed. Check Yourself! 1. Which two kingdoms include bacteria? 2. How do bacteria reproduce? 3. Name two ways that bacteria cause illness. Watch It! III. Draw a simple diagram of a paramecium. Label the cilia, contractile vacuole, and eyespot. What is a Protist? A. Protista is a diverse kingdom of organisms that is divided into 3 main groups: (plant-like), (animal-like) and (fungus-like). B. Algae are important aquatic (the base of aquatic food webs) and produce most of earth s oxygen. They may be unicellular or multicellular (seaweed). C. Protozoa are unicellular, aquatic protists that are similar to animals. Protozoa have to allow them to accomplish life functions: 1. Adaptations for include a whip-like tail called a flagellum, tiny hair-like projections called cilia, or extensions of the cell membrane called pseudopodia. 2. An adaptation for is the contractile vacuole. This vacuole pumps excess water out of the cell, since these aquatic organisms may take in more water than necessary by. 158
Check Yourself! 1. What are the 3 groups of protists? 3. An adaptation for is the eyespot. This structure allows for responses to light. D. In protozoa, reproduction is asexual through, and many algae use fragmentation. Some protists may exchange DNA though. 2. Name 2 reasons that algae are important. 3. What protist causes the disease malaria? IV. List 2 ways that fungi can reproduce: 1. 2. Check Yourself! 1. How do fungi obtain food? E. Some protists are pathogenic. is a disease caused by parasitic protists called plasmodia. Malaria is transmitted by a mosquito. Any organism which transmits/carries a disease without being affected by the disease is called a. The symptoms of malaria include headache, shaking, chills, and fever. Some forms of malaria may lead to comas, convulsions, or even death. How are fungi different from plants? A. Fungi are eukaryotic organisms that may be uni- or multicellular. B. Fungi are. They obtain food through extracellular digestion, secreting digestive chemicals and absorbing nutrients. C. Fungi may reproduce, such as budding in yeast. Spores may be used for asexual or sexual reproduction. D. Some fungi are pathogenic. is yeast that is a normal inhabitant of moist human epithelial tissue, such as the throat and vagina. Certain circumstances can cause Candida to become pathogenic by growing too rapidly and releasing harmful substances. This leads to conditions such as oral thrush, yeast infections, and/or kidney infections. 2. What reproductive structure can be used for sexual or asexual reproduction? 3. What is the name of the fungus that causes thrush? 159
Concept Map: Reproduction of Simple Organisms Reproduction Viruses requires becaus not living Bacteria Asexual by Exchang e DNA by conjugation Protozoa binary fission Asexual by Exchang e DNA by Algae fragmentation Fungi Asexual by or produces spores may be Word Bank: Conjugation Sexual Protists budding host binary fission asexual 160
Unit 5 / Module 12 Problem Solving Set 1. On the diagram of the virus, label the capsid and nucleic acid. 2. On the diagram of the bacterial cell, label the cell wall, chromosome, and plasmid. 3. Based on the diagrams of viruses and bacteria shown above, compare and contrast the structure of these organisms. Viruses BOTH Bacteria 4. On the viral reproduction diagram, label each stage of the LYTIC CYCLE. 5. Answer the questions below about the diagrams of bacterial reproduction. What TYPE of asexual reproduction is shown in the diagram? EXPLAIN what is occurring in the diagram of bacterial conjugation. 161
6. Use the diagram to explain how vaccines work. How vaccines work: 7. Identify each of the following examples as ACTIVE or PASSIVE immunity: a. A child is vaccinated for measles b. A mother breast-feeds her child, passing antibodies c. A child contracts the chickenpox virus 8. Identify the type of movement being used by the protists in the diagrams. eyespot 9. The Euglena shown below is a protist that has the ability to move (animal-like) but also contains chloroplasts (plant-like). Explain the importance of an eyespot: 10. The paramecium shown below lives in a freshwater environment. Contractil e Explain the importance of the contractile vacuole: 11. Identify TWO ways that simple organisms are beneficial: i. ii. 12. Identify the disease being described: a. Caused by a virus that attacks the lymph nodes and lungs, leading to headaches, muscle ache, and pustules on the skin. b. Caused by a bacterium that attacks the lungs, leading to coughing, chest pain, fatigue, and fever. Can be treated with antibiotics. c. Caused by the protist Plasmodium, but mosquitos are vectors. Leads to headache, shaking, chills, fever, and possible death. d. Caused by yeast living in epithelial tissue, producing harmful material 162
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