BIO 2110 Lecture 13: Lecture 13 - Biological Rhythms
3 Mar 2017
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Document Summary
Ligand gated ion channels, g coupled proteins, receptor enzymes. Eg phototrophism using the hormone auxin (elongation on same side as auxin) Accumulation of auxin on the side without light. The leaves have a rapid respond to close the leaves. They don"t have a nervous system but can still respond quickly. Protects against insects, smaller leaf surface to land on. Light touch --> only the leaves, hard touch --> the entire petiole moves. Rapid change in ion flux which changes the osmotic pressure. Tiny hairs across the leaf and if two are touched within 6 seconds, the thing closes. Potassium normalizes the electric difference and the ion potential. Means: periodic biological fluctuation in an organism that corresponds to and is in response to periodic environmental change. Peaks during day to prepare organism for activity. Controlled by synchronizing internal cycles with precise external stimuli. Bar headed goose migration and sand piper migration.
