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BIOLOGY UNIT II EXAM OUTLINE PLANTS Xylem transport water Phloem transport “sap” Sclerenchyma Fibers are for structural support Plant cells are special because they have cell walls, plasmodesmata , chloroplasts, polyploidy, self-fertilization Photosynthesis takes place in the thylakoid membranes (most abundant membranes on earth) Rubisco f ixes carbon in the Calvin Cycle by attaching a CO2 molecule to a five carbon sugar to create a 6 carbon cycle (rubisco is the most abundant protein on earth) “Green Revolution” has made plants with drought and salt tolerance, improved breeding with male sterility for hybrid seeds, improved nutritional traits like high-lysine seeds, improved crops after harvest like delay of fruit ripening, use as bioreactors like plastics, oils and drugs produced in plants and controlling crop pests with herbicide tolerance, Making transgenic plants works so well because the infection with Agrobacterium is efficient and because entire plants of many species can be regenerated from calli tissue treated with appropriate plant hormones Expressing antigens in fruit––vaccination by eating (e.g., hepatitis) Secondary metabolites are special chemicals that are not used for cellular metabolism; they may attract pollinators and/or repel/poison predators. They are frequently stored in the large vacuoles of plant cells. o Humans make commercial use of secondary plant metabolites as fungicides, insecticides, rodenticides, and pharmaceuticals. o Atropine from belladonna plant used as pupil dilator in eye exams o Other secondary metabolites coffee, poppy, coca, marijuana, tobacco o Salicylic acid is a defense molecule produced by willow trees and is the active ingredient of aspirin. In plants, it functions in both the “systemic acquired resistance” to pathogens such as viruses, and it also functions as a hormone to signal unexposed areas of a plant that an infection is underway Plant hormones Ethylene o Promotes fruit ripening and leaf abscission; inhibits stem elongation and gravitropism o Ethylene is positive feedback it causes an increase in its own production o The signal transduction pathway through which ethylene produces its effects includes two membrane proteins: an ethylene receptor (ETR1) and a membrane protein (EIN2) that acts through a second messenger to activate a transcription factor (EIN3). o EIN3 turns on the genes that produce ethylene’s effects in the cell. o Transgenic application:
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o Plants are being made in which ethylene production is inactivated. Therefore, the fruits can’t ripen by themselves. The fruits will be picked when large but green, transported to the site of sale, then exposed to exogenous ethylene to control ripening. Auxin:
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This note was uploaded on 11/12/2010 for the course BSCI BSCI 110B taught by Professor Johnson during the Spring '09 term at Vanderbilt.

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