CONCEPT ESSAYS: 1992: L. PETERSON/AP BIOLOGY Biological recognition is important in many processes at the molecular, cellular, and organismal levels. Select three of the following, and for each of the three that you have chosen, explain how the process of recognition occurs and give an example. a. Organisms recognize others as members of their own species. b. Neurotransmitters are recognized in the synapse. c. Antigens trigger antibody responses. d. Nucleic acids are complementary. e. Target cells respond to specific hormones. 1992: L.PETERSON/AP BIOLOGY Survival depends on the ability of an organism to respond to changes in its environment. Some plants flower in response to changes in day length. Some mammals may run or fight when frightened. For both of these examples, describe the physiological mechanisms involved in the response. 1993: L. PETERSON/AP BIOLOGY Membranes are important structural features of cells. (a) Describe how membrane structure is related to the transport of materials across a membrane. (b) Describe the role of membranes in the synthesis of ATP in either respiration or photosynthesis. 1994: L. PETERSON/AP BIOLOGY Discuss how cellular structures, including the plasma membrane, specialized endoplasmic reticulum, cytoskeletal elements, and mitochondria, function together in the contraction of skeletal muscle cells. 1995: L. PETERSON/AP BIOLOGY The problems of survival of animals on land are very different from those of survivial of animals in an aquatic environment. Describe four problems associated with animal survival in terrestrial environments but not in aquatic environments. For each problem, explain an evolutionary solution. 1995: L. PETERSON/AP BIOLOGY Angiosperms (flowering plants) and vertebrates obtain nutrients from their environment in different ways: (A) Discuss the type of nutrition and the nutritional requirements of angiosperms and vertebrates. (B) Describe 2 structural adaptations in angiosperms for obtaining nutrients from the environment. Relate structure to function. (C) Interdependence in nature is evident in symbiosis. Explain two symbiotic relationships that aid in nutrient uptake, using examples from angiosperms and/or vertebrates. (Both examples may be angiosperms, both may be vertebrates, or one may be from each group.)