The development of vaccinations began when Edward Jenner noticed that ________ rats were always present when people contracted bubonic plague 2.people who had earlier exposure to cowpox did not develop smallpox 3.people who drank water from a particular public water pump developed cholera 4.bacteria removed from a sick animal would cause the same illness if injected into a healthy animal

An antigen is ________. 1.any molecule that the body recognizes as foreign 2.the DNA or RNA of an infective pathogen 3.an alternate term for an MHC complex 4.the collection of circulating proteins which kill or tag microbes 123

Nonspecific immunity includes ________. 1.the skin and epithelial linings like those in the lung 2.macrophages 3.lymphocytes and neutrophils 4.the liver and spleen 123

Not commonly considered to be helpful, ________ is a defensive response that ________ all of the choices 2.sneezing, expels irritants from the nasal cavity 3.mucous, traps microbes in a sticky fluid 4.diarrhea, flushes microbes from the intestines

Memory cells play a vital immune role ________. 1.when you are first exposed to a pathogen 2.when you are exposed to a disease for the second time 3.in non-specific immunity 4.in the primary immune response 123

B cells are primarily activated by the activities of ________. 1.antigen and complement 2.plasma cells 3.helper T cells 4.macrophages 123

The relationship between antigen and antibody is most like ________. 1.a battery and a flashlight 2.a hand and a glove 3.a hammer and a nail 4.a left foot and a right foot 123

Cytotoxic T cells protect the body by ________. 1.making antibodies that float free in the body fluids 2.activating the complement system 3.secreting toxic substances that destroy pathogens 4.phagocytizing invaders 123

What is the value of lymph passing through the lymph nodes? 1.nodes store millions of B cells and can release them in an emergency 2.macrophages examine the lymph for the presence of foreign objects like bacteria 3.nodes produce most of the circulating white blood cells 4.nodes pump lymph to keep it moving 123

Your cells have a unique MHC (major histocompatibility complex). Directions for producing MHCs come from ________. 1.the thymus 2.the bone marrow 3.inherited DNA 4.the helper T-cells 123

How is inflammation helpful? 1.it inhibits bacterial growth 2.it limits mobility and facilitates rest of an injured structure 3.it improves the availability of nutrients to improve the repair process 4.all of the choices 123

Over time, antigen receptor diversity within a population ________. 1.decreases because less fit individuals die and their genes are removed from the gene pool 2.increases because the elements that form the receptor genes spontaneously rearrange 3.decreases because receptor patterns that are not used are selected against 4.increases because each new generation is born of parents that survived childhood diseases 123

Which of the following develops after the primary immune response? 1.complement proteins 2.macrophages 3.memory cells 4.antigens 123

Activated complement brings about the death of a microbe when it ________. 1.organizes into a membrane pore and causes lysis of the cell 2.activates a chemotaxic response in certain phagocytic cells 3.mediates interactions between immune cells 4.all of the choices 123

There are many types of immune system cells. The cell that produces antibodies is the ________. 1.macrophage 2.phagocyte 3.T lymphocyte 4.B lymphocyte 123

Which of the following provides long-term immunity? 1.memory cells 2.cytotoxic T cells 3.antigens 4.complement proteins 123

In gene therapy ________. 1.vaccines modify the genes to produce more efficient antibodies 2.the receptors that microbes use to locate target cells are modified 3.a virus is used to insert a functional gene into a patient's DNA 4.injections of antibodies modify the genes of pathogenic microbes 123

During antigen presentation, MHCs are used to ________. 1.help various immune cells bind to one another 2.form presentation complexes with antigenic fragments of the pathogen 3.facilitate the exchange of costimulatory signals between immune cells 4.all of the choices 123

The antigen binding site of an antibody is formed from the ________. 1.constant regions of the heavy and light chain 2.constant regions of two light chains 3.variable regions of the heavy and light chain 4.variable regions of two heavy chains 123

The enzymes present within the AIDS virus ________. 1.dissolve the membrane of the target cell to facilitate entry 2.build proteins that will assemble into new AIDS viruses 3.build DNA from RNA, a process called reverse transcription 4.break down sugars to produce ATP needed for viral replication 123