VIRUSES Chapter 18 Bacteria Viruses Bacteria 1 Viruses

VIRUSES Chapter 18 Bacteria Viruses & Bacteria 1

Viruses • NOT considered living therefore viruses are NOT placed into any kingdom • Viruses are not cellular • Viruses do not carry out respiration • Viruses are non motile • Viruses do not grow • Viruses can not make proteins • Viruses no metabolism or homeostasis 2

Viruses • Viruses are NON LIVING particles (sub cellular) that can reproduce only when in a living cell. • Found basically everywhere ( Air, Water, Soil) • Viruses are smaller than prokaryotes. • Viruses can only be viewed w/electron microscope. • Viruses are pathogens • BACTERIOPHAGE is a special type of virus that infects only bacteria (bacteria eaters) 3

Viruses • Viruses even though they are non living are called parasites b/c they feed on lining things • HOST CELL is a cell in which a virus reproduces • REVERSE TRANSCRIPTASE is an enzyme that when injected into a host cell, it will copy viral RNA into DNA 4

Virus LYTIC CYCLE 1. Virus attaches to a host cell. 2. Virus injects its nucleic acid into the host cell. 3. The host DNA is destroyed and the virual genes are copied. 4. New virus particles are assembled. 5. The host cell breaks open and the new virus particles are released. 5

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BACTERIA • PROKARYOTE – NO internal membrane organelles – NO NUCLEUS • CIRCULAR DNA – Plasmid • All bacteria are unicellular – Some may colonize but are not multicellular as the activities of the cells of the colony are not specialized 7

Bacteria • KINGDOM • Old five (5) kingdom hierarchy – Monera • New six (6) kingdom hierarchy – Eubacteria – Archaebacteria • Scientists think – 1 st bacteria (anaerobic) 8

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BACTERIA • When you are sick there is something in your body that makes you feel nauseous, what is it? It’s bacteria. Bacteria are a germ that you can’t see with the naked eye. You might not be able to see them but there are billions of them all over you. Sometimes bacteria are bad but sometimes it helps us fight infections. One form of bacteria causes bad breath. If your gums and teeth are healthy then the problem is your tongue. You might already know, but bacteria come in all different shapes and sizes. Typically there are three certain shapes of bacteria round, rod-shaped, and spiral bacteria. They are also classified into groups very specifically. 10

BACTERIA • Classified many different ways. One way is by shape • Three basic shapes – BACILLUS (rod) – SPIRRILUM (spiral) – COCCUS (sphere) 11

Bacillus (rod) Coccus (Sphere) Spirrilum (Spiral) 12

Typical bacterial Cell 13

Archaebacteria “Extremists” • Ancient ones • Live in extreme environments • Ribosomal RNA is different from Eubacteria r. RNA • Three types – Grouped by where they live • Marshes/sewage/digestive tracts some mammals • Water w/high salt conc. Great Salt Lakes/Dead Sea • Deep cracks in the ocean floor • Autotrophic and/or Heterotrophic 14

Archaebacteria Unicellular Prokaryotes Form and Metabolism are different than in any other organisms Found in areas sheltered from evolutionary alteration unchanging habitats Resemble earth’s early environment living relics • surviving representatives of first ages of life on earth Produce methane and cluster together as a group No peptidoglycan (murien) cell wall Get food by sunlight, organic compounds, and inorganic compounds 15

Eubacteria • True bacteria • Heterotrophic – live almost everywhere – Some are parasitic – Some are saprophytes – Some use organic molecules as their food • Photosynthetic Autotrophs – live in places w/sunlight – Cyanobacteria – introduced oxygen into the earth’s atmosphere • Chemosynthetic – break down and release the energy of inorganic cpds. w/sulfur & nitrogen • Convert atmospheric nitrogen into nitrogen-containing cpds that plants need. 16

BACTERIA • Unique cell walls • Cell wall needs to stay intact. • Penicillin kills bacteria by causing holes to develop in the cell wall 17

BACTERIA How does a bacterium’s cell wall protect it? The cell wall prevents water from entering by osmosis and causing it to burst 18

Bacteria A. Where is the genetic material of a bacterium found? B. What structure do some bacteria use to move? • A. As a plasmid or circular chromosome within the cell’s cytoplasm • B. Flagella 19

Bacteria more beneficial ones than pathogenic ones • Some Uses – Farming – Medical industry – Food industry (Swiss cheese/yogurt/sour cream /vinegar/sauerkraut/ pickles – Nitrogen fixation – Recycle nutrients 20

Good Bacteria • Some of the good bacteria are in our stomachs, helping digest food. While others are important in the production of dairy products such as cheese, yogurt, buttermilk, and sour cream. Just remember that you can eat foods that have bacteria just as long as it's good bacteria 21

Good Bacteria • A researcher in Canada is trying to encourage the use of bacteria pesticides to grow on crops. Scientists at a university located in Winnipeg did some tests to see how this bacteria would effect the plants. After adding an exceptional amount of water they added bacteria that causes food poisoning. These bacteria include E. Coli and Salmonella. This prevented insects from eating the plants. This will also reduce the amout of chemical pesticides that could harm are ecosystem. 22

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Nitrogen fixing bacteria 24

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Bacteria - uses • Nitrogen fixation – Most of the Earth’s nitrogen exists in atmospheric gas form. 80% of the Earth’s atmosphere • All organisms need nitrogen but very few can use it directly from the atmosphere. • Several species of bacteria have enzymes that convert atmospheric nitrogen into ammonia • Some bacteria convert the ammonia into nitrites and nitrates • Plants then use the nitrites/nitrates • ONLY bacteria can carry out these processes 26

Bacteria Some evolutionary adaptations in bacteria • • • Reproduce Rapidly by BINARY FISSION High rate of mutation Exist in Adverse conditions Can utilize substances harmful to other organisms Simpilcity of the cell structure Some are aerobic Some are anaerobic Some are facultative aerobes (both w/wo oxygen) Some are obligate anaerobes – w/o oxygen – release energy by fermentation 27

Bacteria • Some can carry out Nitrogen Fixation – a process by which bacteria convert nitrogen gas (atmospheric nitrogen) into ammonia. • Reproduction – Commonly – Binary Fission (asexual) – Conjugation (sexual) may occur as well – is a simple form of reproduction. Conjugation brings about an exchange of genetic material between bacterial cells – allows for diversity 28

Why can’t bacteria reproduce by mitosis or meiosis? • B/c they do NOT have a nucleus, and instead of pairs of chromosomes they have one circular chromosome and varying numbers of smaller circular pieces of DNA called plasmids. 29

Bacteria • Bacterial reproduction can occur rapidly – every 20 minutes by binary fission. Why does this not occur? • They would cover the surface of the Earth within a few weeks. They would run out of nutrients and water, they would poison themselves with their own wastes 30

Bacteria • ENDOSPORE – structure in some bacteria that is resistant to adverse environmental factors (protects the bacteria) • ENDSPORE – bacterial form that is in a state of slow metabolism and that does not reproduce. • ENDOSPORES – may be harmful to other organisms. – C. botulinum endospores will produce toxins and result in causing botulism in other organisms (deadly food poisoning) 31

Most Common Bacteria • Escherichia Coli • E coli is a very common Actually it is the most common species of bacteria. Theodore Escherich discovered the bacteria, E. Coli. This bacteria does not have one particular environment that it lives in. It could be found in places such as hot springs and radioactive wastes. E. Coli also live in the intestine and help to break down food 32

Bad Bacteria • Bacterial Meningitis is an infection that affects the lining of the brain and the spine. There have been reports about this disease causing death lately, but this illness can be treated if it is found early. It can be caused by bacteria, widespread virus, and chemicals. Bacteria forms of Meningitis are more serious. This bacteria can get into your bloodstream. If you don’t treat it then it could cause paralysis, severe brain damage, and damage to other organs. 33

• Salmonella is another type of bacteria. It is commonly found in poultry, eggs, meat, and water. If you have a pet turtle or bird they may carry it. It attacks the stomach and intestines. To keep from getting Salmonella you should wash your hands after touching anything that might carry Salmonella. 34

Bacteria • TOXIN – poison produced by some bacteria – Food poisoning (both salmonella/botulism) Some bacteria are pathogenic • Streptococcus pneumoniae – causes pneumonia • Name tells you that the bacteria are arranged as long chains of round cells (coccus-sphere shaped or round) • Gonorrhea. Syphilis/Tuberculosis/ Diphtheria/Tetanus 35

Bacterial Food Poisoning • Fungi, viruses, and bacteria can cause food poisoning; however, bacteria related food-borne illnesses are the most common. Bacteria usually develops on raw foods. Remember it is a decomposer and it breaks down material as it feeds on it. If you don’t cook your food thoroughly then you allow bacteria to grow and spread on your food 36