Exocytosis and secretion

The exocytosis and secretion lab deals with the induction of stimulus-dependent secretion, a topic well studied in Tetrahymena. This lab can also be linked to evolution of defense mechanisms in lower eukaryotes. Students induce secretion of a gelatinous capsule around the whole cell (visually similar to the jelly capsule surrounding frog eggs) in response to Alcian Blue. Cell reaction is captured by microscope mounted digital cameras using real time and time lapse exposures. Survival of the cells and ability to secrete a second capsule in response to stimulation are explored. Classroom modifications include examining the role various stimulants and calcium concentration in the secretory process. Students are encouraged to formulate their own questions and design experiments to answer them, e.g. what effect does media or temperature or cell density have on secretory behavior.

Capsule formation

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Module Protocols
High School

Relevant Concepts

Subcellular organization; Defense Mechanisms; Relationship of Structure to Function; Science as a Process; Interorganismal Relationships; Survival Mechanisms

Next Generation Science Standards Relationships

High School: [HS-LS1-2 | HS-LS1-6

Middle School: MS-LS1-1 | MS-LS1-2

NYS Science Curriculum Guideline Relationships

Key Ideas 1.1 | 1.2 | 1.3 | 4.5 | 4.6