Viruses & Bacteria 1

Transcription

1 Viruses & Bacteria 1

2 UNIT GOALS A)Students will derive the relationship between single-celled and multi-celled organisms and the increasing complexity of systems. B) Compare how structures and function vary between the six kingdoms. C) Examine the evolutionary basis of modern classification systems. d) Compare and contrast viruses with living organisms.

3 A virus is a nonliving particle with a simple structure. Composed of a nucleic acid (DNA or RNA) surrounded by a protein coat. 2

4 Virus Structure Capsid - The capsid is the protein shell that encloses the nucleic acid; Three functions: 1) it protects the nucleic acid from digestion by enzymes, 2) contains special sites on its surface that allow the virus to attach to a host cell, and 3) Allow virus nucleic acid penetrate the host cell s membrane and, in some cases, to inject the infectious nucleic acid into the cell's cytoplasm. Envelope - Surrounds the capsid. Composed of two lipid layers interspersed with protein molecules 3 Or RNA Or RNA

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7 Viral Nucleic Acid The nucleic acid of each virus encodes the genetic information for the synthesis of all proteins. Only a few groups of viruses use DNA. Most viruses maintain all their genetic information with the single-stranded RNA. 5

8 Viruses, such as the influenza virus, that have RNA as their genetic material mutate more often that DNA viruses. 6

9 Animation Lytic Cycle 7 1.The virus attaches to a host cell and injects its nucleic acid into the cell. 2.The viral nucleic acid is immediately replicated, eventually causing the host cell to burst, releasing new viral particles. 3.These new viruses then attack other cells.

10 Lysogenic Cycle Animation After the virus embeds its nucleic acid into the chromosome of the host cell, the viral nucleic acid is replicated along with the host cell s DNA. Then the virus becomes dormant, sometimes for years without the host knowing. The virus may suddenly become active, resuming the lytic cycle, which will eventually destroy the host 8 cell.

11 Overview: Lytic and Lysogenic cycles 9

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13 Are viruses alive? 11 Do they Can They: Reproduce? meet Obtain and use energy? the Grow, develop, and die? criteria Respond to the environment? for life?

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15 Vaccines 13 Clip on next slide

16 EXTRAS Prion-is a type of infectious agent made only of protein. Chronic wasting disease, (in deer and elk), mad cow disease All of these diseases affect the structure of the brain or other neural tissue, and all are untreatable and fatal. 16

17 Viroids small naked single-stranded RNA molecules that infect plant cells and cause disease. Smaller than viruses, viroids are not enclosed in a protein coat of any kind. They generally consist of less than 400 nucleotides and do not contain any genes. 17

18 Compare and contrast viruses with living organisms. Viruses 6 kingdoms of Living things Examples to include: -Mode of nutrition? -Characteristics of living things -Reproduction -Structure -Homeostasis? - Cell structures?

19 Diseases Caused by Viruses

20 Influenza 1918 pandemic 20 to 40 million people More people died of influenza in a single year than in four-years of the Black Death Bubonic Plague from 1347 to Known as "Spanish Flu" or "La Grippe" the influenza of was a global disaster

21 Polio Polio is a contagious, historically devastating disease that was virtually eliminated from the Western hemisphere in the second half of the twentieth century. Although polio has plagued humans since ancient times, its most extensive outbreak occurred in the first half of the 1900s before the vaccination, created by Jonas Salk, became widely available in People who have abortive polio or nonparalytic polio usually make a full recovery. However, paralytic polio, as its name implies, causes muscle paralysis - and can even result in death. In paralytic polio, the virus leaves the intestinal tract and enters the bloodstream, attacking the nerves (in abortive or asymptomatic polio, the virus usually just stays in the intestinal tract). The virus may affect the nerves governing the muscles in the limbs and the muscles necessary for breathing, causing respiratory difficulty and paralysis of the arms and legs. Although the acute illness usually lasts less than 2 weeks, damage to the nerves could last a lifetime. What's the Future of Polio? Through intensive vaccination programs, a coalition of organizations in 1999 decided to work toward world eradication of polio by Between 1988 and 1998, wild-type polio was eliminated from North America, South America, and Europe. But polio still exists in Africa, as well as India and some of its neighboring countries.

22 People can be exposed to Ebola virus from direct contact with the blood and/or secretions of an infected person: contact with objects, such as needles, that have been contaminated with infected secretions

23 Human Immunodeficiency Virus

24 Lassa Fever The number of Lassa virus infections per year in West Africa is estimated at 100,000 to 300,000, with approximately 5,000 deaths. In some areas of Sierra Leone and Liberia, it is known that 10%-16% of people admitted to hospitals have Lassa fever, which indicates the serious impact of the disease on the population of this region.

25 Chickenpox Chickenpox is a very contagious viral disease that causes an itchy outbreak of skin blisters. The chickenpox virus spreads from person to person by direct contact with fluid from broken chickenpox blisters. Chickenpox is usually a mild disease. However, in adults and children with weakened immune systems, chickenpox can cause serious complications and even death. A vaccine is now available to prevent chickenpox.

26 Hantavirus

27 Measles Diseases of childhood that causes a skin rash. Serious complications, such as pneumonia, croup or encephalitis, can occur. The disease starts with a cold, fever, cough, conjunctivitis (red eye) and fatigue. Three days later, a red blotchy rash starts on the face - then spreads to the rest of the body, including the feet. The fever starts to go down on the second or third day of the rash. There may be some fine peeling of the skin after the rash fades. Most patients are ill for about seven days; IS IT CONTAGIOUS? VERY. It is most common in late winter and early spring. Most people have been exposed to the disease days before they have any symptoms. Spread by coming in contact with the saliva of someone who has the disease through coughing, kissing or sharing of eating utensils. Once you have had a case of measles you have lifetime immunity (protection) to the disease.

28 Mumps

29 Rabies Most often transmitted through the bite of a rabid animal

30 Smallpox Infection usually occurred by inhalation of virus acute, with fever, malaise (discomfort/out of sorts), headaches, and backaches. The initial toxemia phase lasted 4-5 days. On about the third or fourth day, the characteristic rash appeared. First, it appeared on the buccal (mouth) and pharyngeal (throat) mucosa, the face, and the forearms. Within a day, it spread to the trunk and lower limbs. The lesions usually protruded from the skin and are firm to touch. About 8 weeks after onset of the rash, the lesions dried up and became crusted by day 14. By the end of the third week, most crusts had fallen off, with the exception of the palms and the soles. The outcome of infection was either death or recovery with immunity. In 1966, the World Health Organization started a program for the worldwide eradication of smallpox. Through intensive case finding and vaccination of direct and indirect contacts, the disease was finally eradicated on December 9,1979.

31 Hepatitis C Before a blood test was discovered in 1989 to screen for HCV, this was the most frequent hepatitis to be acquired from blood transfusions and blood products. Up to half of those with chronic disease will go on to develop liver failure and need a transplant. Each year, 8,000 to 10,000 people die in the United States because of hepatitis C-related cirrhosis or HCVrelated liver cancer. Hepatitis B This type is essentially a blood-borne virus with other bodily fluids being infectious, notably semen and saliva, and is often transmitted from mother to fetus. Hepatitis Hepatitis is a disease that impairs liver function either temporarily or permanently, sometimes even leading to death. It can be initiated by a host of factors, but primarily by viruses. Drugs also can cause hepatitis but when the specific drug is discontinued, the liver usually returns to normal.

32 Herpes Infection caused by the Herpes Simplex Virus (HSV), which resides in the nerve ganglia after the initial exposure to the virus. Because the virus is so effective at "hiding out" in the nerve cells, the body is never able to eliminate the herpes virus completely. Instead, after the initial infection, the body produces antibodies which show up in the blood stream. Blood tests which indicates the presence or lack of these antibodies. The antibodies make it easier for the body to recognize and attack the virus when it re-emerges from the nerve cells in the form of an outbreak. For this reason, out breaks following the primary outbreak usually diminish in frequency and intensity over time. Some people may never have another outbreak.

33 Retrovirus Has an RNA genome that is converted to DNA in the host cell HIV Reverse transcription ANIMATION

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36 MONERA EUBACTERIA ARCHAEABACTERIA 1.Largest 2.Unicellular 3.Prokaryotic 4.Most use oxygen but some are anaerobic. 1.Unicellular 2.Prokaryotic 3.Ancestors of Eukaryotes 4. Lives in harsh environments. 2

37 Round Rod Spiral 3

38 Cell membrane Ribosome Pili Flagella Plasmids Chromosome Cell Wall 4

39 Gram Staining Method scientist use to determine cell wall type in bacteria 5

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42 Nutrition -obtaining energy 8

43 Releasing Energy Obligate Aerobes Facultative Anaerobes Obligate Anaerobes Must Have Oxygen With or Without Oxygen Cannot Have Oxygen 9.1

44 Take in food and Eliminate Waste Take in food by endocytosis Eliminate waste through the cell membrane by exocytosis. 9.2

45 Bacteria Reproduction Sexual Asexual Conjugation Binary Fission 10 Exchange DNA Split

46 11 E. coli undergoing conjugation

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49 14 Endospores are a method of survival.

50 15 ENDOSPORE FORMATION

51 BACTERIA HELPFUL Soil---decomposing HARMFUL Diseases Plants---nitrogen fixation Humans---digestive system Humans---Food:cheese, yogurt, sauerkraut, & soy sauce. Humans--- Genetic Engineering 16 Photosynthesis produces oxygen

52 Diseases caused by Bacteria 17

53 18 Bacterial Diseases release poisons that Harm the body breaking down Tissues for food

54 Treatments Vaccines»Before infection Antibiotics»After infection

55 Alexander Fleming 19

56 antibiotics can be used to destroy bacterial cells 20

57 Different ways to prevent a bacterial infection. 1) Sterilization: Uses heat or chemicals to kill bacteria from objects.

58 21 2. Skin and surfaces that have been in contact with raw meat should be washed thoroughly, food should be cooked properly, and contaminated water should be boiled. 2. Avoid contact with an infected organism or organisms that carry disease-causing microorganisms. Plague swept across Europe in the Middle Ages, half of the population died. Bacteria transmitted through the bite of a flea.

59 Why do we refrigerate our food? Slows down the growth of bacteria. Slows down spoilage.

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61 22 EOCT QUESTIONS

62 23 The outer layer of a virus is made of A) carbohydrates B) lipids C) nucleic acids D) proteins

63 24 A vaccinations B blood transfusions C vitamin C D antibiotics

64 25 A bacteria B fungi C protozoa D viruses

65 Why is food preserved by canning in glass containers normally safe for later consumption? A The glass allows solar radiation to kill the bacteria that were in the food. B Bacteria are destroyed by extreme heat in the glass container. C Bacteria are removed from the food before it is placed in the glass container. D The glass container prevents oxygen. 26

66 Microorganisms such as bacteria are able to change and adapt much more quickly than other organisms. Bacterial populations, for example, are able to build a resistance to antibiotics within months, whereas compounds that are toxic to animals remain toxic to animals for many years. One reason for their rapid adaptability is that microorganisms A are highly motile B have a short life span C have specialized organelles D are chemosynthetic Recognize the role of evolution to biological resistance