Notes for Final Exam

Notes for Final Exam - Pages: 821-835..974-995..1045-1117...

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Unformatted text preview: Pages: 821-835..974-995..1045-1117 Name of Plant Hormone: Function: Auxins Stem elongation, differentiation, apical dominance Cytokinins Cell division, germination Gibberellins Seed, bud, and fruit development, stem elongation Abscisic Acid Inhibits growth, closes stomata, prevents germination Ethylene Promotes fruit ripening, programmed cell death, leaf abscission, response to mechanical stress Brassinosteroids Normal growth and development, xylem differentiation, pollen tube elongation Strigolactones Apical dominance, germination, attracts mycorrhizal fungi to the root Gland: Hormone: Posterior Pituitary Gland Oxytocin and antidiuretic hormone Anterior Pituitary Gland Growth hormone, prolactin, follicle- stimulating hormone, LH, TSH, ACTH Thyroid Glands Calcitonin Parathyroid Glands Parathyroid hormone Pancreas Insulin and glucagon Adrenal Glands Epinephrine and norepinephrine Gonads Androgens, estrogens, and progestin Pineal Gland Melatonin Stem Elongation o Auxin is produced in the apical meristem o It is transported down the shoot o Goes from a high concentration at the top to a low concentration at the bottom (goes with its concentration gradient) o A high concentration of auxin inhibits stem elongation while a low concentration of auxin promotes stem elongation Elongation never happens in the meristem; always happens further down the shoot Apical Dominance o The apical meristem dominates the plant so branches do not grow out o When the meristem is cut, branches (lateral shoot development) can form o Cytokinin is produced in the root meristem and its concentration gradient is from the root up; promotes lateral branching o Auxin and cytokinin have opposite impacts on root branching Plant Rhythms o Some plant processes (i.e. flowering) follow a daily cycle, suggesting that plants have rhythms o Photoperiodism : Some plants flower only when days are long (summer) or short (winter) Night length is critical for flowering and the night must be uninterrupted Plants contain pigments called phytochromes (one part photoreceptor and the other part protein kinase) o Short-day, Long-night Plant Example: At night, Pfr is slowly, naturally converted to Pr Plants track time based on the accumulation of Pr A flash of light activates the protein kinase, destroying all of the Pr production and resetting the night length back equal to 0 Chemical Signaling in Animals o Two majors organ systems are involved: Endocrine : hormones are secreted into the bloodstream Nervous : neurotransmitters are secreted into synapses between neurons Differences: the endocrine system broadcasts the signal throughout a broad area while the nervous system sends the signal directly to a target cell via neurons Similarities: many hormones are neurotransmitters, some neurons secrete hormones, and cells are communicating with other cells Types of Hormones o Lipid-soluble: goes through the cell membrane and binds to cytoplasmic...
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This note was uploaded on 02/08/2012 for the course SCIENCE 1201 taught by Professor Bill during the Spring '11 term at LSU.

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Notes for Final Exam - Pages: 821-835..974-995..1045-1117...

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