BACTERIA

STRUCTURE Do not have a nucleus FLAGELLUM: A tail that rotates for movement GENETIC MATERIAL (DNA): Found free floating in the cytoplasm

BACTERIUM STRUCTURE

Classifying bacteria Bacteria can be classified based on: cell wall type Shape Arrangement Respiration (aerobic vs. anaerobic) Ability to create own food

Thermophiles – live in hot environments such as hot springs (temperatures over 45°C) Methanogens – grow on carbon dioxide and hydrogen gas to produce methane – exist in volcanic deep sea vents and mammals’ intestines Halophiles – live in saline (salt) environments (salt flats)

Bacteria reproduce asexually

HELPFUL BACTERIA Bacteria are used for: Decay – decompose dead matter Fermentation – small intestine (helps digestion) Creation of foods – vinegar, cheese, yoghurt Nitrogen Fixing Bacteria – create nitrates needed for soil and found in roots of legumes

Harmful bacteria Bacteria can cause infections: Pathogen – disease causing agent (bacteria/virus) Create toxins  cause inflammation  death EXAMPLES: Tuberculosis, Typhoid, Diptheria

Harmful BACTERIA Streptococcus – seen in strep throat, pneumonia, etc. Helicobacter pylori – seen in stomach ulcers Streptococcus mutans – one of the bacteria that cause cavities Myobacterium tuberculosis – bacteria causing tuberculosis Vibrio cholerae – bacteria that causes cholera

DEVELOPING AN INFECTION Entrance – through opening Attach to specific host – via proteins (antigens) Survive host defences (immune response) Cause disease – produce toxins Exit Host – release through urine, feces, sneezing, coughing

HOMEWORK: Read p. 224-231 Answer Q 1,3,4 Answer p. 231 Q 1, 4

Fighting Disease

DISEASE PREVENTION Practice good hygiene (wash hands) Practice a healthy lifestyle: Eat well Stay active Protect yourself (ie. Sunscreen)

THREE LINES OF DEFENcE There are 3 lines of defence offered by the immune system External Defence Lymphatic System Antibody Formation

External Defence Human Skin – protective barrier Respiratory Tract has cilia and mucus that will trap bacteria In eyes, bacteria are destroyed by enzymes in tears

Lymphatic System As microorganisms are collected in the lymphatic system they are destroyed by specialized white blood cells Macrophage – WBC that eats harmful bacteria Pus – dead WBC and bacteria

Antibody Formation ANTIBODY: proteins that inactivate foreign substances by attaching to its surface Each antibody is specific We can only create antibodies to diseases that we have previously been exposed to ANIMATION: Immune System Response

immunity the production of antibodies to destroy a pathogen Active Immunity body produces own antibodies  lifelong through vaccines Passive Immunity Antibodies are injected in blood Babies get antibodies from their mothers

antibiotics kill bacteria ONLY Before prescribing antibiotics: Doctor will get a sample/sputum test to ensure it is a bacterial infection (not viral) Take antibiotics until it is finished

Overuse of antibiotics Can create “super-bugs”  antibiotic resistant bacteria Infections are difficult to treat long-lasting illnesses  death Ex: MRSA – drug resistant bacteria (hospitals)

Vaccines Weakened version of bacteria or virus increase active immunity (body’s own antibodies) Once pathogenic bacteria and virus enters the body, antibodies recognize it, attach to it and destroy it before it causes damage to our bodies

Getting the flu vaccine Annual vaccine that protects against flu virus that mutates every year Will cause active immunity against 3-4 flu viruses No side effects

HOMEWORK: Answer p. 231 Q 5, 7, 8, 9