Ever wonder why Robin Williams is hirsute,while Patrick Stewart is follecularlychallenged? Well, the answer is in their DNA-
Viruses• Microscopic (can’t see with the naked eye)• nonliving particle• Invades and reproduces inside a host.• Contains DNA or RNA The red spots are the AIDS virus, they are surrounding other body cells.
Virus Multiplication• Active – Become sick within hours or days• Hidden – Illness can be delayed for weeks, months, or years – Triggered by environment?
Bacteria• Microscopic• Prokaryotes (means they don’t have a nucleus)• Living• Contains DNA
Shapes of bacteria• Spherical• Rodlike• Spiralshaped• They can also be in chains – Spherical chain
Bacteria Multiplication• Sexual reproduction – Two parents – Conjugation (transfer of genetic material through bridge)• Asexual reproduction – Binary Fission-Simply splitting in two
More on Growth• Rapid, as fast as once every 20 minutes• Continues until they run out of the basics – Food – Air – Space
Parasites• Organisms that live on or in a host and cause harm.• Examples: Viruses, Bacteria, and tapeworms.• Can a bacteria be a host?
How many can there be? • These bubble-headed creatures are called bacteriophages, viruses that target bacteria. The head holds DNA and the tail acts as a needle attaching to a specific site on the bacterial cell wall, the virus squirts DNA through the tail into the bacterium. Ouch! They are among the smallest of organisms. You could fit about 680,000 of these creatures on the head of a pin.
What can you do?• Get Vaccines• Personal Hygiene• Use Disinfectants• Lines of Defense – Skin – Mucus barriers – Immune System
Defenses cont. .This is a human macrophage, found in yourblood that wards off infection. It is homing inon a chain of nasty Streptococcus bacteria.Hitching a ride aboard the macrophage is asphere-shaped lymphocyte. Both macrophageand lymphocyte can be found near the site ofan infection, and the two act in concert to helpeliminate it.
The deadliest pandemic in history was the 1918influenza epidemic, the Spanish Flu. By the time the"Spanish lady" departed, 22 million people had died ofthe mysterious killer.Positively identifying the 1918 flustrain is made more difficult by thefact that the flu virus is capable ofvery rapid mutations
Personal example• A doctor stationed at Camp Devens, a military base just west of Boston, writes to a friend, and fellow physician, of the conditions to be found there as influenza was making its presence felt.
VaccinesExisting flu shots are 70 percent to 90 percent effective at preventing flu in healthy young people• 50 percent effective in the elderly, (And even if the vaccines dont prevent the flu, they do tend to reduce symptoms and serious complications).
High Risk Groups • aged 65 and older • with chronic diseases affecting the heart, lung or kidneys • with diabetes, immunosuppression, or severe anemia • people in contact with doctors, nurses and nursing-home staff
Prevention • "The current U.S. plan in the event of a pandemic is to vaccinate virtually the entire population," says epidemiologist Nancy Arden. • Despite its advantages, less than 60 percent of the high-risk population gets the flu shot each year.