Bacteria UNIT 3 - Chapter 19

Prokaryotes Definition: single-celled organisms that lacks a NUCLEUS OLD Classification – MONERA Prokaryotes called BACTERIA All BACTERIA were in the Kingdom – MONERA CURRENT Classification Prokaryotes (BACTERIA) are divided into 2 very different KINGDOMS EUBACTERIA ARCHAEBACTERIA

Eubacteria vs. Archaebacteria BOTH: Prokaryotes, unicellular, autotrophic or heterotrophic EUBACTERIA: Larger kingdom Cell Wall contains PEPTIDOGLYCAN EX: E. coli and Streptococcus ARCHAEBACTERIA: Some similar DNA sequences to Eukaryotes (thought to be ancestors) No PEPTIDOGLYCAN in cell wall Live in EXTREME conditions (3 types): Methanogens—poisoned by O2 Thermaphiles—live in extreme temps. Halophiles—live in high saline

E. coli Eubacteria include a variety of lifestyles such as are classified into the kingdoms of Eubacteria Archaebacteria include a variety of lifestyles such as live in harsh environments such as Infecting large organisms Thick mud Living in soil Animal digestive tracts Salty lakes Hot springs E. coli Methanogens

Shapes of Bacteria

Obtain and Use ENERGY AUTOTROPHS (make their food) Photoautotrophs: use photosynthesis to make chemical energy out of sunlight Found near lots of light Chemoautrophs: get energy from inorganic chemical reactions HETEROTROPHS (take in ORGANIC materials) MOST PROKARYOTES If food is not handled correctly, bacteria may eat it and in the process leave poisonous chemicals behind

Bacteria in Nature DECOMPOSERS “Natures Recyclers” Help the ecosystem “Recycle” and break down dead matter into simpler substances Works as sewage treatment; produces purified water; releases nitrogen and CO2 EXAMPLE: Nitrogen Fixation Process by which nitrogen is converted into a form plants can use Nitrogen gas (N2) must be change into ammonia (NH3)

Nitrogen-FIxers Rhizobium (bacteria) Attached to the roots of soybeans and legumes Convert nitrogen gas to ammonia Ammonia helps plant (soybean)

Bacteria and Disease PATHOGENS (disease causing) Cause disease by 2 methods Damage TISSUES of organism Mycobacerium tuberculosis Cause Tuberculosis by breaking down lung tissue Release TOXIN (poisons) Salmonella and E. coli Common types of food poison release toxins Streptococcus Causes strep throat releases toxin into the blood stream

Prevention and Treatment Vaccines: dead or weakened pathogens (bacteria or viruses) used to induce formation of antibodies or immunity against the pathogen (must be given before) Antibiotic: block growth and reproduction of bacteria (cure bacterial diseases) Disease Pathogen Prevention Tooth decay Lyme disease Tetanus Tuberculosis Salmonella food poisoning Pneumonia Cholera Streptococcus mutans Borrelia burgdorferi Clostridium tetani Mycobacterium tuberculosis Salmonella enteritidis Streptococcus pneumoniae Vibrio cholerae Regular dental hygiene Protection from tick bites Current tetanus vaccination Vaccination Proper food-handling practices Maintaining good health Clean water supplies

Human Uses of Bacteria FOOD PRODUCTION: cheese, yogurt, pickles, INDUSTRIAL: digest oil, remove waste and poisons, synthesize drugs, genetic engineering CONTROLLING BACTERIA STERILIZTION: means of destroying Heat (boiling water) Chemicals (disinfectants) INHIBITING or SLOWING growth Refrigeration (low temps just slow) Salt, Vinegar and sugar

VIRUSES UNIT 3 chapter 19

Viruses STRUCTURE: CHARACTERISTICS: Particles of Nucleic Acid (DNA, RNA), proteins, and lipids CORE – contains DNA or RNA CAPSID – outer protein coat CHARACTERISTICS: Many different sizes and shapes Only REPRODUCE when infecting living cell (virus is not a cell) Viruses are very specific

Review of Living and NON-living 8 Characteristics Made of Cells Reproduce Based on Genetic Code Grow and Develop Obtain and use energy Respond to environment Homeostasis Evolve Viruses are considered NON-living. Why?

Viruses are NON-Living NON-life like (contrasting) Not made of cells Do not reproduce independently Do not Grow/Develop/Respond to environment Do not Obtain and use energy Life-like (comparing) Evolve Contain DNA or RNA

Viral Infections are Specific Highly specific to type of cells they infect. Plant viruses do not infect animal cells Animal viruses only infect certain species of animals BACTERIOPHAGES: Virus that infects bacteria EX: T4 and Lambda

Types of Viral Infections: LYTIC Virus Enters cell and causes it to BURST Quickly!!! Virus attaches to cell wall Virus injects DNA into cell Virus takes over cell metabolism and produces its own proteins & nucleic acids Proteins and Nucleic acids combine to form NEW viruses Enzyme breaks down cell wall & NEW viruses leave to infect other cells

Bacteriophage (virus) attaching Bacteria Bacteriophage protein coat Bacteriophage DNA Bacterial chromosome Bacteriophage attaches to bacterium’s cell wall Bacteriophage enzyme lyses the bacterium’s cell wall, releasing new bacteriophage particles that can attack other cells. Lytic Cycle Bacteriophage injects DNA into bacterium Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles Bacteriophage Bacteriophage DNA Bacteriophage protein Bacteriophage takes over bacterium’s metabolism, causing synthesis of new bacteriophage proteins and nucleic acids

Types of Viral Infections: LYSOGENIC TWO Cycles LYSOGENIC LYTIC DIFFERS from Lytic because… DNA is embeded into host DNA Virus does NOT KILL cell right away

Steps of LYSOGENIC Infection Virus injects DNA DNA forms a circle (Prophage) DNA circle (prophage) combines with the bacteria DNA Virus DNA (prophage) replicates with bacterial DNA Virus DNA (prophage) exits bacterial DNA (forms own circle) Begin Lytic cycle… New viruses Burst cell and leave

Lysogenic Infection Section 19-3 START: Bacteriophage injects DNA into bacterium Bacteriophage DNA (prophage) can exit the bacterial chromosome Bacterial chromosome Bacteriophage DNA Lytic Cycle Lysogenic Cycle Bacteriophage DNA (prophage) may replicate with bacterium for many generations Bacteriophage enzyme lyses the bacterium’s cell wall, releasing new bacteriophage particles that can attack other cells Bacteriophage DNA forms a circle Prophage Bacteriophage proteins and nucleic acids assemble into complete bacteriophage particles Bacteriophage DNA inserts itself into bacterial chromosome Go to Section:

LYSOGENIC Cyle to LYTIC Cycle Lysogenic cycle (latent or dormant) The virus will switch to LYTIC cycle under ADVERSE conditions (Stress, radiation, chemical change)

Diseases: Polio, Measles, Mumps, AIDS, Flu, Rabies, Yellow Fever, Colds Lytic Infections (colds-adenoviruses) Lysogenic Infections (Herpes, EBV, HPV) (Epstein-Barr EBV) Lytic-Mononucleosis / Lysogenic-predisposed to lymphoma (HPV) lytic-genital warts / lysogenic cervical cancer Retroviruses (RSV, HIV, HTLV, FLU) Genetic material is RNA and makes copy into DNA Retro- means “backwards”; develops mutations quickly RSV (Rous sarcoma virus) can lead to sarcoma; HTLV can lead to leukemia… virus can transform/mutate host DNA

Human Viruses Nucleic Acid Type of Virus Diseases DNA RNA Oncogenic viruses Retroviruses Adenoviruses Herpesviruses Poxviruses cancer cancer, AIDS respiratory infections Chickenpox, Mono smallpox

WARNING Following slides contain graphic pictures. Herpes sores…

Herpes Simplex 1

Herpes Simplex II

Symptoms and Prevention Best way to protect against a viral infection is PREVENTION Vaccines (for some) Only good before virus Stimulates immune response SYMPTOMS: Caused when virus attacks and destroys body cells Lytic cycle (see symptoms) Lysogenic cycle (virus is dormant, no symptoms….but still contagious)

AIDS (Acquired Immune Deficiency) CAUSED BY: HIV (Human Immunodeficiency Virus) Virus destroys helper T cells EFFECTS: Depresses cell-mediated immunity, Deficit in antibodies Immune system turned upside down Increasing frequency of infections, often rare types, Lesions on skin, Dementia TRANSMITTED: In body secretions (blood, semen, vaginal secretions) Sexual Intercourse, use of IV needles, some documented cases by oral sex

HIV