Biology

12th

grade

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AP Bio Unit 4 MC - CollegeBoard

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  • 1. Multiple Choice
    30 seconds
    1 pt

    An antigen can induce an immune response in a host organism. Antigens are targeted by antibodies that are produced by the organism’s immune system in response to contact with the antigen. Antibodies are specific to antigens. Many different cell types are involved in immune responses. Which of the following best describes the role of cell-to-cell communication during a response to an invasion of antigens?

    A macrophage cell engulfs a pathogen in the blood.

    Antigens attaching to receptors on memory B cells stimulate the memory B cells to become plasma cells.

    Antigen-presenting cells engulf antigens at the first exposure.

    Chemicals that are secreted from antigen-presenting cells then activate helper T cells.

  • 2. Multiple Choice
    30 seconds
    1 pt

    Adjacent plant cells have narrow channels called plasmodesmata that pass through the cell walls of the connected cells and allow a cytoplasmic connection between the cells.


    Which of the following statements best describes a primary function of plasmodesmata?

    They prevent the cell membrane from pulling away from the cell wall during periods of drought.

    They eliminate the need to produce signaling molecules and eliminate the need for cells to have receptors for signaling molecules.

    They increase the surface area available for attachment of ribosomes and thus increase protein synthesis.

    They allow the movement of molecules from one cell to another, enabling communication between cells.

  • 3. Multiple Choice
    30 seconds
    1 pt

    A hydrophilic peptide hormone is produced in the anterior pituitary gland located at the base of the brain. The hormone targets specific cells in many parts of the body.


    Which of the following best explains a possible mechanism that would enable the hormone to efficiently reach all of the target cells in the body?

    The hormone interacts with the nerves at the base of the brain and directs signals to the target cells through the nervous system.

    The hormone diffuses into target cells adjacent to the anterior pituitary gland, where the hormone is degraded.

    The hormone is released into the bloodstream where it can be transported to all cells with the correct receptors.

    The hormone moves through cytoplasmic connections between cells until it has reached all cells with the correct intracellular binding sites.

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