Bacteria and viruses

1. Bacteria and viruses Chapters 20.1-20.3 By: Kendall Aldridge, Kathy Garcia and Ranah Stewart

2. Important Vocabulary • capsid: Protein coat surrounding a virus • pathogen: Disease-causing agent • prophage:Bacteriophage DNA that is embedded in the bacterial host’s DNA • binary fission: Type of asexual reproduction in which an organism replicates its DNA and divides in half, producing two identical daughter cells • endosperm: Food-rich tissue that nourishes a seedling as it grows

3. Important Vocabulary • mutation: Change in the genetic material of a cell • conjugation: Process in which paramecia and some prokaryotes exchange genetic information • heterotroph: Organism that obtains food by consuming other living things; also called a consumer • antibiotic: Group of drugs used to block the growth and reproduction of bacterial pathogens

4. Viruses • A virus is a nonliving particle made of proteins, nucleic acids and sometimes lipids. • Viruses can only reproduce by infecting living cells.

5. Viral Infections • Inside living cells, viruses use their genetic information to make multiple copies of themselves. Some viruses replicate immediately while others initially persist in an inactive state within the host. • In a lytic infection, virus cells enter bacterial cells and make copies of themselves and cause the cell to burst or lyse.

6. Viral Infections • Common Cold– where a viral protein make new copies of the viral DNA inside the body. * Symptoms- • HIV/AIDS– the deadly disease called Acquired Immune Deficiency Syndrome(AIDS), is caused by an RNA virus called Human Immunodeficiency Virus(HIV).

7. Viral Diseases • Many of these diseases can be prevented with vaccines • Examples of a viral infections: • Cold • Influenza • SARS • HIV • Mono • Rabies • Smallpox

8. Viral Diseases • Viruses can cause disease by directly destroying living cells or by affecting cellular processes in ways that upset homeostatis

9. Lysogenic Infections • This is when a host cell is not immediately taken over. Instead the viral nucleic acids inserted into the host cell’s DNA, whereas it is copied along with the host DNA without damaging the host.

10. Benefits of Vaccines • Vaccine: Preperation of of weakened or killed pathogens or inactivated toxins • Stimulates your body’s own immune system • Immune system takes memory of the pathogen so it is easier to fight off next time • Immunity: the body’s ability to destroy pathogens or inactivated toxins

11. Superbugs • Resistant to a whole group of antibiotics that transfer drug-resistant genes from one bacterium to another through conjunction

12. Prions • Short for “protein infectious particles” • Infectious • Proteins that can cause other proteins to fold incorrectly • Causes degeneration in the brain and spinal cord • Mad Cow Disease

13. Emerging Diseases • An unknown disease that appears in a population for the first time or a well-known disease that suddenly becomes harder to control • The pathogens that cause emerging diseases are particularly threatening to human health because human populations have little or no resistance to them, and because methods of control have yet been developed

14. Bacteria • A large domain of single-celled, prokaryote microorganisms • They come in three basic, different shapes: spores, rods and spirals • Bacteria is found EVERYWHERE!!

15. Archaea • A single-celled individual or species • They have no nucleus • They used to be mistaken as bacteria in the past

16. Classifying Prokaryotes • Prokaryotes are unicellular organisms that lack a nucleus. • Prokaryotes have DNA, like other cells, but their DNA is not found in a membrane-bound nuclear envelope. It is found in the CYTOPLASM. • Prokaryotes are classified as BACTERIA or ARCHAEA- two of the three domains of life.

17. Importance of Prokaryotes • Prokaryotes are essential in maintaining every aspect of the ecological balance of the human living world. Decomposers • By assisting in breaking down, or decomposing, dead organisms, prokaryotes supply raw materials and help maintain equilibrium in the environment. • They are also essential to industrial sewage treatment, helping produce purified water and chemicals that can be used as fertilizers.

18. Importance of Prokaryotes Producers • Photosynthetic prokaryotes are among the most important producers on the planet. • These species alone may account for the primary production in the open ocean, and food chains everywhere are dependent upon prokaryotes as producers of food and biomass. Nitrogen Fixers • Prokaryotes are the only types of organisms that can convert Nitrogen into useful forms.

19. Importance of Prokaryotes Human Uses of Prokaryotes • Prokaryotes, especially bacteria, are used in the production of a wide variety of foods and other commercial products. • Some bacteria can even digest petroleum and remove human-made waste products and poisons from water. • Others are used to synthesize drugs and chemicals. • Biologists continue to discover new uses of prokaryotes.

20. Structure and Function Shape, Size, and Movement • Prokaryotes have three different kinds of shapes. • Bacilli- rod shaped; Cocci- spherical shaped; Spirilla- spiral or corkscrew shaped • You can tell the difference between because of their movement. • Some prokaryotes don’t move at all; others are propelled by their flagella(tale at the end of a prokaryote that produces a wave-like movement); some glide slowly along a layer of slimelike material they secrete.

21. Structure and Function Nutrition and Metabolism • Prokaryotes need a supply of chemical energy, which is stored in the form of fuel molecules such as sugars. • Energy is released from these fuel molecules during cellular respiration, fermentation, or both. • Prokaryotes have diverse ways to obtain and release energy. • Some species are able to change their method of energy capture or release depending on the conditions of their environment.

22. Structure and Function Growth, Reproduction, and Recombination • Prokaryotes reproduce through binary fission, which is a type of reproduction in which an organism replicates its DNA and divides in half producing two daughter cells. • Because binary fission does not involve the exchange or recombination of DNA, it is a form of asexual reproduction.

23. Structure and Function Growth, Reproduction, and Recombination Continued • Mutation is one of the main ways that prokaryotes evolve. • In prokaryotes, mutations are inherited by daughter cells produced by binary fission. • Many prokaryotes exchange genetic information by a process called conjunction. • During conjunction, a hollow bridge forms between two bacterial cells, and genetic material, usually in the form of a plasmid, moves from one cell to another.

24. Bacterial Pathogens • Bacteria cause disease by destroying living cells or by releasing chemicals that upset homeostasis by: • Damaging host tissue (tiberculosis) • Releasing Toxins (Botulism) Methods for controlling bacteria: removal, disinfectants, food storage and processing, sterilization by heat, vaccines, and antibiotics!