Immune+System+HW+Pathogens+CC

immune system Immune System Homework. (These answers require you to summarize information. Most should be more than one sentence. Images will help.)

PATHOGENS 1. What is a pathogen? A pathogen is a biological agent that causes disease or illness to its host. They can affect any unicellular or multicellular organism. 2. What are the body's three lines of defense against pathogens? bacteria, immune system, normal flora 3. Write a one paragraph summary of bacteria. Bacteria are just one cell, and they don't have a nucleus. There are three forms, the bacillus, coccus, and spirillum. Bacteria sticks to things due to the cell wall, and what is on the cell wall. Bacteria have plasmids, sex pilus, flafellum, ribosomes, nucleoids, a plasma membrane, a cell wall, and a capsule. Each of these have their own funtion for the cell, including protecting the cell or allowing DNA to transfer. 4. Write a one paragraph summary of viruses. A virus comes from outside the body, and someone must catch a virus. Viruses are simply chemicals outside of the body, but once inside the body and in cells they multiply. Viruses are not made up of cells, like bacteria and they must live of something else. Viruses are what cause disease, such as a cold or the flu. A virus is made up of two parts: proteins on the outside or nucleic acids on the inside. 5. What is an emerging virus? Viruses that emerge from one location to a new location. Because viruses can and do change so frequently, it is possible that the virus emerges and then the immune system doesn't know how to fight it off, even if it has fought it off before. IMMUNE SYSTEM 6. What is an antibody? What do they do? Antibodies are proteins to help protect or defend the body from an antigen. Antibodies and antigens fit together like a key and a lock. 7. What is B Cell? B cell's purpose is to produce plasma and memory cells. These help fight off viruses that the body has fought off before. 8. What is a Cytotoxic T Cell? It kills virus-infected cells 9. What is a Helper T Cell? It regulates the immune system 10. What is an antigen? How does the body respond to an antigen? An Antigen is like an invasion of a foriegn object that triggers are response of the immune system (antibody)