Download such as bacteria and viruses. Platelets

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Period: ____
Key Points on Viruses:
1. Viruses
a. Considered to be non-living because they cannot reproduce without the help of
another organism, call the host. The common cold is caused by a virus.
b. Structure
i. Core – DNA or RNA that contains instructions for how the virus operates.
ii. Outside – protein surrounds the DNA or RNA core, called the coat.
c. Function
i. A virus attaches itself to a living cell and injects its genetic material into the
host cell.
ii. The genetic material tells the cell’s ribosomes to make new viruses
iii. The new viruses fill up the host cell and cause it to burst, killing the host cell
and releasing new viruses.
iv. These new viruses then infect and kill more cells.
d. Symptoms – seen all over the body: body aches, fever
e. Treatment
i. Antiviral drugs can shorten a viral infection but each drug works on only one
type of virus. Scientists have made antiviral drugs to treat HIV, Hepatitis B and
C, and influenza (flu).
ii. Vaccines can prevent infection but are not useful once infected.
iii. Antibiotics DO NOT work for viral infections.
2. Immune System Response
a. WBCs recognize the antigens on viruses and kill the host cell to prevent the virus
from reproducing.
b. The WBCs will also produce antibodies against the virus so if infection occurs in the
future, the virus will be destroyed before causing illness.
c. Vaccines – a substance that resembles a disease-causing virus
i. Made from weakened or killed virus which trains the body's immune system
to recognize the substance as foreign, destroy it, and "remember" it.
Key Points on Blood and Bacteria:
3. Blood – fluid that travels through organisms
a. Functions
i. Carries nutrients and oxygen to cells and waste away from cells.
ii. Regulates temperature and pH (holds it steady)
iii. Helps fight infections from foreign invaders
b. Structure
i. Plasma – makes up most of blood, mainly water but also some molecules
ii. Blood cells – cells that float in the plasma, doing different jobs.
c. Types of Blood Cells
i. Red (erythrocytes) – contains hemoglobin, a protein that carries O2.
ii. White (leukocytes) – remove old cells and attack infectious agents
(pathogens) such as bacteria and viruses.
iii. Platelets – forms clots which stop up blood vessels when they break, stopping
bleeding. A scab.
4. Bacterial Infections
a. Infection – an organism invades another organism to get its resources
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Period: ____
b. Release toxins which interfere with normal cell function
c. Symptoms (affects) - redness, heat, swelling and pain in the specific area that the
infection occurs.
d. Treatment – antibiotics are effective against bacterial infections.
e. Body Response
i. The body’s immune system also fights infections.
ii. Proteins, called antigens, on the surface of bacterial invaders that tell white
blood cells (leukocytes) that the bacteria should be attacked.
iii. WBCs will also produce antibodies, specialized proteins, that will stay in the
organism’s blood forever. These will recognize the antigens of this specific
invader if it infects the organism again, allowing it to be destroyed much
more quickly the second time.
iv. If the virus is later encountered, the immune system can more easily
5. Fungal Infections
a. A fungus is a member of a large group of eukaryotic organisms that includes
microorganisms such as yeasts and molds, as well as mushrooms.
b. People with compromised immune systems have a higher risk of getting fungal
infections.
i. The 1980s saw a large number of people become sick
because of a rare infection of the fungi Pneumocystis
pneumonia or PCP. Doctors realized all of the sick
people had weak immune systems, which they
eventually discovered were being destroyed by HIV.
ii. People with cancer that are undergoing
chemotherapy also have weakened immune systems
and are more likely to have fungal infections.
c. Fungi can attack cells of the eyes, nails, hair, and especially
skin.
i. Tinea pedis, or athlete’s foot, as well as ringworm are
caused by fungi. The symptoms of these are itchy and
peeling skin.
d. Molds can cause problems with the respiratory system
(mouth, nose, lungs, trachea) if someone is allergic to them.
i. Some molds produce toxins which can poison a person.
6. Treatment - antifungal drugs, usually creams put on affected area.
7. Prevention - keep skin clean and dry, sports clothing should be washed after use, wear
flip-flops if using a community swimming pool or shower since fungal infections are
contagious and can spread from person to person.