Infectious Disease & Bacteria Kingdoms Notes A white blood cell eating bacteria. Small Pox

What is an Infectious Disease? Slide # 2 1. Disease- a condition in which the body does not function normally. 2. Infectious disease: disease caused by the presence and activity of a microbial agent. 3. Epidemic- A local outbreak of a disease concentrated in one area. 4. Pandemic-A worldwide outbreak of a disease

1. What causes infectious ( contagious) disease? a. Pathogen- any disease causing agent b. Examples of Pathogen and Disease:  Virus -HIV causes AIDS  Bacteria -Streptococcus causes Strep throat  Protist - Plasmodium causes Malaria  Fungi -fungi cause athlete’s foot & ringworm Pathogens Are Infectious Agents Slide # 3

1. Airborne: spread through coughing & sneezing. Enter through the nose, mouth, and move to lungs. 2. Contaminated food or water; enter mouth & go to stomach & intestines. 3. Bites from vectors such as mosquitoes, ticks, & fleas that transfer pathogens. 4. Enter through openings in the skin (wounds & when you touch your eyes.) 5. Body fluids – which can be exchanged through sexual activities, pregnancy, & drug needles. How do you get an Infectious PATHOGEN? Slide # 4 Vector Airborne

How to Prevent the Spread of Diseases 1.Good Hygiene- washing hands & keeping hands away from eyes, nose and mouth. 2.Proper cooking & water treatment. 3.Controlling Vectors- spraying for mosquitoes, fleas, ticks, etc. 4.Abstinence from sexual activity. 5.Vaccinations- weak or dead strain of a pathogen that is injected into a person so the body can learn how to recognize and fight off the pathogen. Slide # 5

How are Diseases Treated? 1.Bacterial disease is treated with antibiotics. 2.Viral infections do not have a cure. Many viral infections must “run their course” until the body learns how to get rid of it. 3. Over-the-counter medicines only treat symptoms Slide # 6

Classifying Bacteria into TWO Kingdoms 1.Divided into 2 kingdoms: (Were once one kingdom- “Monera”, before DNA sequences were found to be too different.) a. Kingdom Eubacteria – “modern” bacteria that make up most of what we consider to be bacteria. Live almost anywhere & have cell walls made of peptidoglycan (protein/carbohydrate). E-coli bacteria (yellow) on the head of a needle. Slide # 7

b. Kingdom Archaebacteria “Ancient” bacteria thought to be the ancestor of eukaryotes (all other kingdoms). cell walls do not have peptidioglycan They live only in extreme environments: –Hot- Yellowstone’s many hot springs –Salty-The Dead Sea –No oxygen- Swamps & deep in soil Ex: Thermaphiles in hot springs Halophiles in salty habitats Slide # 8

Colonies of halophiles form a purple-red scum in these salt collection ponds of the Dead Sea Colorful thermaphiles grow in this hot spring. Grand Prismatic Spring, Yellowstone National Park, Wyoming Adam JonesAdam Jones Kingdom Archaebacteria Slide # 9

 1/10 to 1/100 the size of our cells  Unicellular (single celled)  Prokaryotic (no nucleus) CHARACTERISTICS OF ALL BACTERIA Bacteria on the head of a pin. How small? Interactive Link Slide # 10

 Capsule (cell wall) protects from injury & determines shape  Have cytoplasm (cell fluid), ribosomes (make proteins) and cell membrane (maintains homeostasis). Plasmid: circular chromosome may have pili to stick to each other Some move using a tail- like flagella BACTERIA STRUCTURE Slide # 11

1. The capsule is composed of peptidoglycan (a protein/carbohydrate) and has 2 functions: a. Protection against antibiotics b. Supports the cell 2.Identifying the type of cell wall using a technique known as Gram staining is important for diagnostic and treatment purposes. a.Identification method developed by Danish physician Christian Gram. b.Uses crystal violet (purple stain) Bacteria are Classified by: 1. Type of Cell Wall Slide # 12

Bacteria are Classified by: 1. Type of Cell Wall c. Gram positive absorbs the dye and look purple These bacteria have a single cell wall layer made of peptidoglycan. d. Gram negative repels the dye (has a third lipid layer) and look pink Gram negative bacteria are usually more resistant to antibiotics (like penicillin) and cause more severe infections. 2 membranes (lipid layers) Peptidoglycan Cell membrane Antibiotics killing bacteria video link Slide # 13

One way bacteria are classified and named is by their shape; There are three main shapes: Rod-shaped: Bacillus Sphere-shaped: Coccus Spiral-shaped: Spirilium Slide # 14

REPRODUCTION 1. Binary fission: asexual; one bacterium splits to become two identical daughter cells Individual colonies of bacteria Slide # 15

BACTERIAL GROWTH: Binary Fission Bacteria reproduce fast (some every 20 minutes). Limiting factors: food, space, water, temperature, & waste products (toxic) Exponential growth: with each generation the # of individuals born is doubled. In ___one bacterium can produce __bacterial cells! Slide # 16

2. Conjugation: sexual; exchange genetic info. through bridge (pili) –INCREASES GENETIC DIVERSITY REPRODUCTION Slide # 17

3. Endospore: internal spore formed to survive heat, radiation, drying and some chemical disinfectants REPRODUCTION While the outer cell disintegrates, an endospore, such as this anthrax endospore, stays protected by a thick, protective wall. Endospores may be dormant for centuries or more. Slide # 18

HELPFUL BACTERIA Most bacteria and NOT harmful! 1. DECOMPOSERS Most important decomposers on Earth! Sewage Treatment (break down human wastes, food & chemicals 2. FOODS Yogurt, cheese, buttermilk, pickles, sauerkraut, vinegar, sour cream Slide # 19

HELPFUL BACTERIA 3. SYMBIOSIS Nitrogen Fixation: bacteria live on plant roots & turn nitrogen in air into forms that plants can use to make proteins E. coli in human intestines (make vitamins) a mutualisitic relationship E. coli in human intestines (make vitamins) a mutualisitic relationship Slide # MEDICINE Produce antibiotics (tetracycline, erythromyecin) Genetic engineering creates insulin, human growth hormone

HARMFUL BACTERIA PATHOGENS: tetanus (lock jaw), gonorrhea & syphilis (STD’s), typhoid fever, Strep Throat, diphtheria, tuberculosis, cholera, Lyme disease, bubonic plague, Botulism & Salmonella (Types of food poison that release toxins.) Mychobacterium tuberculosis Bacteria cause disease in one of two ways: -Attack cell or tissues directly by breaking them down for food -release TOXINS that travel through the body Slide # 21

Controlling Bacteria 1. Sterilization using high heat and pressure to kill 100% of bacteria and their endospores. 2. Disinfectants are chemical solutions that kill bacteria. They do not kill endospores thus are never 100% effective. a. Examples include cleansers, soaps, detergents, Lysol, etc. b.Overuse of disinfectants, however, increases the likelihood that bacteria will evolve to become resistant to them, becoming more dangerous and difficult to kill. Slide # 22

Food Storage and Processing 1.Refrigeration – slows the growth of bacteria, but does not kill them 2.Pasteurization - uses temperatures below boiling for a set amount of time to greatly reduce the number of microorganisms. 3.Cooking, Boiling, frying, or steaming sterilizes many kinds of food. 4.Using preservatives discourages bacteria growth. 5.Using everyday chemicals such as salt, vinegar, or sugar preserves foods as well. Slide#23

Preventing Disease Antibiotics are compounds that can either weaken the cell walls of bacteria (penicillin) or block the growth and reproduction of bacteria. Overuse of antibiotics is contributing to the evolution of bacteria. Some are becoming immune to the known antibiotics used today, and are becoming difficult to kill. Scientists fear the evolution of “super bugs” in the not too distant future. Slide # 24

Staphylococcus before antibiotics Staphylococcus after antibiotics Antibiotics killing bacteria video link Slide # 25

Bacteria are everywhere! Thankfully most are harmless!