NOTES KEY. Chapter 19 Bacteria (Biotic) and Viruses (Abiotic)

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1 NOTES KEY Chapter 19 Bacteria (Biotic) and Viruses (Abiotic) BACTERIA - PROKARYOTES Page 471 Definition: Single celled organisms that lack a nucleus, the DNA is free floating in the cytoplasm Classifying Prokaryotes 1. Archaebacteria Unicellular and LACK a cell wall of peptidoglycan Key DNA sequences are more closely related to Eukaryotes Live in extreme environments and are named after the environments they live EXAMPLES: Methanogens live in areas with no oxygen like thick mud or intestines Thermoacidophiles live in really high temperatures and low ph (acid) Chemosynthesizers live in deep ocean vents and use organic compounds as energy source. Extreme Halophiles live in salty conditions where other things could not survive. They can live in areas up to 10 times saltier than normal such as the Dead Sea and Great Salt Lake. 2. Eubacteria Unicellular has a cell wall of peptidoglycan that helps protect it and hold its shape Larger of the 2 kingdoms of prokaryotes Wide range of organisms and lifestyle so diverse that some biologists disagree about classifications

2 Obtaining Energy Page Autotrophs Gather energy from sunlight Photoautotrophs gather energy from sunlight Chemoautotrophs gather energy from inorganic,olecules 2. Heterotrophs Most prokaryotes are heterotrophs like us obtaining energy by taking in organic molecules and then breaking them down. Others are photoheterotrophs that do a combination of photosynthesis and inorganic molecules. Would photheterotrophs live in a deep ocean vent? Releasing Energy Most prokaryotes are heterotrophs and conduct cellular respiration that requires oxygen or fermentation that does not require oxygen 1. Obligate aerobes require oxygen (cellular respiration) 2. Obligate anerobes do not require oxygen (fermentation) ex: botulism = food poisoning (causes canned food to swell) 3. Faculative anaerobes do not require oxygen but they are not avoid it either found everywhere, any environment including our digestive system and extremely disinfected hospital rooms! Growth and Reproduction Page 476 When it has almost doubled in size it will reproduce. It will double its DNA and split in half Binary fission Double DNA and split in to two new organisms = asexual and genetically identical Conjugation Exchange of DNA through a hollow bridge between 2 cells = sexual increases genetic diversity of bacteria populations.

3 Endospores when conditions are not favorable for bacteria they can form a thick internal wall to enclose the DNA until more favorable conditions are present again for growth and reproduction. Identifying Prokaryotes Page Shapes 2. cell wall 3. Movement 4. Obtain energy Shapes Bacilli Rod shaped Notes Picture Cocci Spheres (round) Spirilla Spiral Cell Walls 2 types because of cell wall 2 part staining process Gram positive Contain peptidoglycan in the cell wall and absorbs the first Purple purple stain Purple Gram negative Contain a second layer of lipid that abosorbs the PINK second pink stain.

4 Movement Violet = pink Some use a flagella = whip like tail to move BACTERIA in Nature - Page 477 Key concept: Bacteria are vital to the living world. Some are producers that capture energy by photosynthesis. Others help to decompose the nutrients in dead matter allowing other organisms to use the nutrients. Decomposers Nitrogen Fixers Bacteria and Disease Human uses of bacteria Controlling bacteria Notes Helps to recycle the nutrients in the living world All living organisms need Nitrogen to build proteins N2 gas is abundant in the atmosphere but plants need it to be NH3 to use it so Rhizobium fixes the N2 to ammonia NH3 so that the plant can use the Nitrogen to build amino acids and protein. Cause disease in 2 ways 1. Damage tissues 2. Produce toxins that harm See Fig on page 480 Can be very useful in food, industry and biotechnology Sterilization destroys bacteria by subjecting them to heat or chemicals Example Dead tree Dead animals Human waste Rhizobium = Nitrogen fixer = fertilizer factory Streptococcus = Strep throat Tuburculosis E. coli See Page 480 Lysol topical Cooking - Food Refrigeration - Food Canning food - Food

5 How did Louis Pasture contribute to eliminating disease? NOTES KEY Chapter 19 Viruses (Abiotic) (Amoeba Sisters Video 8:00 minutes) What is a virus? Particles of nucleic acid, protein and in some cases lipids that can reproduce only by infecting living cells. They are all very different BUT the one thing they have in common is that once they are inside a living cell they use it to reproduce more viruses. Are viruses alive? NO most biologists do not consider them living because they do not have all the characteristics of life and are not the basic unit of life a cell. Key concept: A typical virus is composed of a core of DNA or RNA surrounded by a protein coat. The protein coat is called a capsid Once inside the virus tricks the cell to reproduce its DNA. Draw and Label different virus structures Page 483 T-4 bacteriophage Tobacco Mosaic Virus Influenza Virus

6 Viruses and Disease Page 486 Cause human diseases such as polio measles, AIS, mumps, influenza, yellow fever, rabies, and the common cold. In most cases the virus attacks and destroy certain cells in the body causing the symptoms of the disease. Best way to prevent disease is by using vaccines. This is a weakened or killed virus that stimulates the immune system to produce permanent immunity to the disease. 1. Viruses and Cancer Some viruses disrupt the genes that regulate cell growth and therefore cause cancer in some animals. 2. Retrovirus Retro mean reverse This virus has RNA and when in a cell copies it into the host DNA causing a change in the DNA sequence. HIV virus that causes AIDS is a retrovirus 3. Prions This is a virus that is only a protein particle no DNA or RNA but causes some disease like Mad Cow disease in animals and humans. RNA vs DNA Viruses RNA virus is unstable and mutates frequently DNA virus is more stable and changes or evolves over a long period of time. Viral Infection page What is a bacteriophage? A virus that infects bacteria cells. Lytic Infection (cycle) (colds) A virus enters a cell, makes a copies of itself and causes the cell to burst Lysogenic Infection (cycle) (HIV) A virus embeds its DNA into the host DNA and replicates along with the host cell.

7 NOTES KEY Chapter 40 Infectious Diseases Define disease: Any change other than an injury that disrupts the normal functions of the body. Some are inherited while others are caused by environmental aspects such as cigarette smoke. Others are caused by agents such as bacteria, viruses and fungi. What is a pathogen? Disease causing agents such as bacteria nad viruses are called pathogen which means sickness makers The Germ Theory of Disease See page Who were the two scientists that contributed to the germ theory? Pasteur and Koch What very common disease in Loudoun County was identified by using the germ theory? Lymes Disease caused by a virus carried in ticks Other common diseases caused by viruses: HIV Flu Chicken pox Mad Cow Yellow Fever Measles Zika Polio Mumps Ebola Herpes Rubella

8 Pathogens and Disease Page 1031 Identify the common methods of disease transmission for viruses and bacteria. Pathogen Viruses Bacteria Air droplets air droplets contact wound Defenses against Disease First Line of Defense The body s most important non specific defense is the skin. Other important defenses include, saliva, mucus and tears. Second Line of Defense The inflammatory response of the immune system is the second line of defense. The infection is met with white blood cells to destroy bacteria and the body may raise your temperature causing a fever. This disrupts the bacteria homeostatis and it can no longer survive. Active Immunity Vacca is the Latin word for cow. Immunity produced by a vaccine is known as active immunity because the body of the recipient has the ability to mount an immediate active immune response against the pathogen. The body makes its OWN antibodies Passive Immunity The body uses another organisms antibodies for a short time because eventually the host body destroys the borrowed antibodies. Example would be a nursing baby who get immunity from some diseases from it s mother but this only lasts a short time.