Viruses and Bacteria Flashcards
What are the living characteristics of bacteria?
-Reproduce only within living cells, but not directly from a pre-existing form like itself.
-do contain DNA or RNA as the nucleic acid but never both.
-Do have a protein wrap or coat called the capsid.
-do contain small amounts of enzyme material.
What are the nonliving characteristics of viruses?
-Non-Cellular
-Do not respire (breathe).
-Do not respond to stimuli.
-Do not grow.
Why are viruses considered have-nots?
-Because they don’t possess many of the typical characteristics typical of real cells.
What are the primary lines of defence against infection?
-Skin (Keeps viruses from penetrating acts as a barrier).
-Covered openings: Mucous, hairs, ear wax, and oil. (Catches viruses).
What are the secondary line of defence against viruses?
-White blood cells (These cells are found in the blood and are able to engulf and destroy potential infecting agents, including viruses. This occurs before they can affect the target tissues). (Phagocytes).
What are the tertiary lines of defence against infection?
-Immune response- The presence of antigens (foreign proteins) or viruses stimulate the production of antibodies. Specific antibodies can recognize specific invaders and deactivate them.
-Immunity may not be permanent, and after a period of time, the number of antibodies begins to “fall off” and booster shots may be necessary for continued protection against diseases.
-Mutations in the virus enable it to not be recognized by antibodies.
-Interferon- An active agent against many viruses and other infecting agents. The three types of interferon one type is produced by white blood cells, produced by cells that form connective tissue in skin and other organs, and produced by the body’s immune system.
What are three kinds of virus groups?
-Animal, plant, and bacterial viruses.
