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Bellringer • What is the difference between a bacteria and a virus? • Are bacteria and viruses harmful, helpful, or neither? • If so, how are they harmful, helpful, or neither? Bacteria and Viruses Bacteria • Prokaryotes-single celled organism lacking nucleus Eukaryote, remember? Bacteria: Shapes Shapes: 1. Bacilli-rods 2. Cocci- spheres 3. Spirilla- spiral, corkscrew Bacillus bacteria are rod or sausage shaped 5 Coccus bacteria are sphere or ball shaped 6 Spirillium bacteria have a corkscrew shape 7 The tip of a needle The red and yellow dots are bacteria 8 Metabolic Diversity • Heterotrophs – Must take in organic molecules for energy and supply or carbon – Chemoheterotroph: Most common. – Photoheterotroph: Least common – Use photosynthesis for energy but need to take in organic compounds for a carbon source • Autotrophs – Make their own food. – Chemoautotrophs: make organic carbon molecules but do not require light as a source of energy. – Photoautotrophs: make organic carbon molecules and require light as a source of energy Bacteria: Cell Walls Cell walls: • Bacteria with peptidoglycan absorb violet dye=gram positive • Bacteria with less peptidoglycan absorb red dye=gram negative Bacteria: Motility Movement: • Flagella allow reaction towards chemical or physical signals Bacteria: Reproduction Reproduction: 1. Binary fission-replicates, divides 2. Conjugation-bridge forms, genetic transfer; Diversity! 3. Endospore- enclose DNA, remain dormant until better conditions; forms spores Endospore CONJUGATION 13 Bacteria Functions in Biosphere 1. 2. 3. 4. Decomposer (chemical recycling) Nitrogen Fixers Bioremediation Human uses for food Helicobacter pylori is the pathogenic bacteria that can causes ulcers 15 Leprosy is a bacterial infection that decreases blood flow to the extremities resulting in the deterioration of toes, ears, the nose and the fingers. 16 LYME DISEASE 17 TUBERCULOSIS 18 STRUCTURE • • • • • 19 Nonliving Composed of Nucleic acid and protein Cause many diseases Virology – Study of Viruses Comparison of Viruses and Cells below Char. Of Life Virus Cell Growth No Yes Homeostasis No Yes Metabolism No Yes Mutation Yes Yes Nucleic acid DNA or RNA DNA Reproduction Only within host cell Independently by cell division Structure Nucleic acid core, protein covering, some have envelope Cytoplasm, cell membrane, etc.. Viruses Virus- particles of nuclei acid and protein which reproduce by infecting living things DRAW and label Tobacco Mosaic Virus causes tobacco plants to develop a pattern of spots Some virus are pushed out by the cell, taking some of the cell membrane with them. 22 Viruses • Lytic infection-virus enters cell, makes copies, bursts out of cell Viruses • Lysogenic infection- virus embeds DNA into DNA of host cell and replicated along with host cell’s DNA Viruses Retroviruses- contain RNA as genetic info; reverse transcription takes place (HIV) Viruses Prions- contain no DNA or RNA, only protien (Mad Cow Disease) Diseases Caused by Bacteria and Viruses • Bacteria produce disease in one of 2 general ways. Some damage the cells and tissues of the infected organism directly by breaking down the cells for food. Others release toxins that travel throughout the body interfering with the normal activity of the host. Vaccine: preparation of weakened or killed pathogen. • Antibiotics: compounds that block the growth and reproduction of bacteria Viral Diseases • Like bacteria, viruses produce disease by disrupting the body’s normal equilibrium. • Viroid; single stranded RNA molecules that have no surrounding capsids. • Prions: protein infectious particles. Viruses and Human Disease • Control and Prevention of spread. – Vaccination & Antiviral drugs • Ex.) chickenpox vaccine, AZT, Acyclovir, protease inhibitors. • Emerging Viruses – exist in isolated habitats – Do not usually infect humans unless environmental conditions favor contact. • Several viruses are now linked to cancers such as leukemia, liver cancer, Burkitt’s lymphoma, cervical cancer. 29 Which US President had polio? 30 31 HERPESVIRUSES BACK 32 RHABDOVIRUSES BACK 33 RETROVIRUSES BACK 34