Chapter 19

Describe the structure of a typical bacterium and a typical virus.

How do bodily secretions help protect against infection?

What roles do B cells and T cells play in the immune response?

Binary fission A. allows bacterial cells to produce more plasmids; B. is a type of sexual cell division that viruses undergo; C. allows immune cells to replicate; D. is the method by which bacteria replicate

Viral replication A. occurs only inside living cells; B. requires that copies of the viral genome be produced; C. requires that copies of viral proteins be synthesized; D. all of the above

The immune system A. has a gene for each antigen; B. undergoes genetic rearrangement in response to different antigens; C. is able to make many antigen receptors by rearranging the DNA of immune cells; D. can always devise an antibody that will bind to an antigen

Autoimmune diseases result when A. a person's endocrine system malfunctions; B. liver enzymes malfunction; C. B cells attack T cells; D. the immune system fails to differentiate between self and nonself cells

Which of the following cell types divides to produce cells that make antibodies? A. helper T cells; B. B cells; C. cytotoxic T cells; D. all of the above

Helper \(T\) cells secrete substances that A. help prevent leukemia; B. prevent bacteria from entering cells; C. boost B-cell and cytotoxic T-cell response; D. inhibit reverse transcriptase; E. stimulate the thymus to make more \(\mathrm{B}\) cells

Lo9 The immune system can recognize a virus you have been exposed to once because A. you harbor the virus for many years; B. we have genes to combat every type of virus; \(\mathrm{C}\). a cell that makes receptors to a virus multiplies on exposure to it and produces memory cells; D. a copy of the viral genome is inserted into a memory cell.

Which of the following is not involved in the second line of defense? A. natural killer cells; B. inflammation; C. complement proteins; D. macrophages; E. T lymphocytes

True or false: The AlDS virus attacks antibodies against unrelated pathogens, weakening the immune system's ability to fight off many diseases.

True or false: Allergic reactions occur when the body can't make antibodies against an antigen.