Biol 101: Final Exam Terms
45 Cards in this Set
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antibiotics
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chemicals that either kill bacteria or slow their growth by interfering with the function of essential bacterial cell structures.
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binary fission
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a type of asexual reproduction in which one parental cell divides into two.
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population
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a group of organisms of the same species living together in the same geographic area.
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evolution
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change in allele frequencies in a population over time.
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fitness
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the relative ability of an organism to survive and reproduce in a particular environment.
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natural selection
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differential survival and reproduction of individuals in response to environmental pressure that leads to change in allele frequencies in a population over time.
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adaptation
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the response of a population to environmental pressure, so that advantageous traits become more common in the population over time.
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directional selection
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a type of natural selection in which organisms with phenotypes at one end of the spectrum are favored by the environment.
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stabilizing selection
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a type of natural selection in which organisms near the middle of the phenotypic range of variation are favored.
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diversifying selection
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a type of natural selection in which organisms with phenotypes at both extremes of the phenotypic range are favored by the environment.
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virus
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an acellular infectious particle consisting of nucleic acid surrounded by a protein shell.
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immune system
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a system of cells and tissues that acts to defend the body against foreign cells and infectious agents.
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immunity
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the resistance to a given pathogen conferred by the activity of the immune system.
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pathogen
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infectious agents including certain viruses, bacteria, fungi, and parasites.
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innate immunity
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nonspecific defenses, such as physical and chemical barriers and phagocytic cells, that are present from birth and are always active.
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adaptive immunity
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a protective response, mediated by lymphocytes, that confers long-lasting immunity against specific pathogens.
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lymphocyte
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a specialized white blood cell of the immune system.
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histamine
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a molecule released by damaged tissue and during allergic reactions.
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inflammatory response
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an innate defense that is activated by local tissue damage.
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phagocyte
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a type of white blood cell that engulfs and ingests damaged cells and pathogens.
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macrophage
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a phagocytic cell that resides in tissues and plays an important role in the inflammatory response.
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neutrophil
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a phagocytic cell in the circulation that plays an important role in the inflammatory response.
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natural killer cell
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a type of white blood cell that acts during the innate immune response to find and destroy virally infected cells and tumor cells.
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interferon
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antiviral proteins produced by virally infected cells to help protect adjacent cells from becoming infected.
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complement proteins
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proteins in blood that help destory pathogens by coating or puncturing them.
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B cells
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white blood cells that mature in the bone marrow and produce antibodies during the adaptive immune response.
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thymus
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the organ which T cells mature.
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T cells
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white blood cells that mature in the thymus and can destory infected cells or stimulate B cells to produce antibodies, depending on the type
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lymph nodes
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small organs in the lymphatic system where B and T cells may encounter pathogens.
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lymphatic system
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the organ system that works with the immune system, allowing B and T cells to respond to pathogens.
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humoral immunity
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the type of adaptive immunity that fights infections and other foreign substances in the circulation and lymph fluid.
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helper T cells
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a type of T cell that helps activate B cells during humoral responses.
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antigen
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a specific molecule (or part of a molecule) to which specific antibodies can bind, and against which an adaptive response is mounted.
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plasma cell
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an activated B cell that divides rapidly and secretes an abundance of antibodies.
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antibody
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a protein produced by B cells that bind to antigens and either neutralizes them or flags other cells to destroy pathogens.
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cell-mediated immunity
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the type of adaptive immunity that rids the body of altered (that is infected or foreign) cells.
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cytotoxic T cells
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a type of T cell that destroys altered cells, including virally infected cells.
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allergy
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a misdirected immune response against environmental substances such as dust, pollen, and foods that causes discomfort in the form of physical symptoms.
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autoimmune disease
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a misdirected immune response in which the immune system mistakenly attacks healthy cells.
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primary response
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the adaptive response mounted the first time a particular antigen is encountered by the immune system.
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memory cell
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a long-lived B or T cell that is produced during the primary response and that is rapidly activated in the secondary response.
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secondary response
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the rapid and strong response mounted when a particular antigen is encountered by the immune system subsequent to the first encounter.
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vaccine
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a preparation of killed or weakened microorganisms or viruses that is given to people or animals to generate a memory immune response.
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antigen drift
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changes in viral antigens caused by genetic mutation during normal viral replication.
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antigen shift
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changes in antigens that occur when viruses exchange genetic material with other strains.
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