web_L32_08BIO311C - BIO 311C April 9, 2008 Cells sense and...

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BIO 311C April 9, 2008
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Cells sense and respond to their environment in various ways. Example 1: food, energy wastes metabolism Living Cell The cell senses sources of food/energy in the environment and responds by utilizing specialized mechanisms to incorporate and metabolize these substances, then selectively discard wastes. Example 2: biological, physical or chemical assault on the cell altered metabolism Living Cell The cell senses an agent of potential damage in the environment and responds by (1) generating a counteractive assault, (2) by moving away from the danger and/or (3) by dying via a carefully regulated mechanism called apoptosis. (adjust, fight back, or die) *
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Members of species of single-celled (unicellular) eukaryotes often communicate via chemical signals. Example : a unicellular species containing males and females sexual signal (a chemical substance) Response that facilitates sexual reproduction Organism of Opposite Sex A unicellular organism senses a signal from an organism of the opposite sex, then responds by preparing to contact the signaling organism in order to combine or exchange genetic information. Organism of One Sex * Also see Textbook Fig. 11.2, p. 202.
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The Cells within a complex multicellular organism communicate extensively via chemical signals. hormone (a chemical substance) Response that may profoundly change characteristics of the cell Receptor Cell (responds to the hormone) A hormone may be defined as: a chemical substance that is produced in one kind of cell of a multicellular organism, and that is sensed by another kind of cell within the organism, eliciting a response in the second kind of cell. (Also see textbook glossary more restricted definition) Donor Cell (produces the hormone) Example : hormonal communication * Moves via body fluids throughout the body
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The results of a signal molecule reaching a responsive receptor cell can be divided into three stages Textbook Fig. 11.5, p. 204.
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This note was uploaded on 09/28/2008 for the course BIO 311C taught by Professor Satasivian during the Spring '08 term at University of Texas at Austin.

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web_L32_08BIO311C - BIO 311C April 9, 2008 Cells sense and...

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