bio final study

bio final study - Leaves typically consist of a broad flat...

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Leaves typically consist of a broad, flat blade and a stalk like petiole, some leaves have small leaflike out-growths from the base called stipules Simple leaves- having a single blade Compound- having a blade divided into two or more leaflets Alternate arrangement- one leafe at each node Opposite-two leaves at each node Whorled- three + at each node Parallel or netted venation (may be palmately netted w/ several veins radiating from a single point or pinnately netted with veins branching along the entire length of the midvein) Stomata small pores (surrounded by two guard cells often associated with special epidermal cells called susidiary cells) in the epidermis that permit gas exchanfe needed for photosynthesis. Mesophyll consists of photosynthetic parenchyma cells divided into palisade mesophyll (photosynthesis) and spongy mesophyll gas exchange Xylem-water exchange Phyloem-conduct sugar produced by photosynthesis to the rest of the plant Monocot- leaves have parallel venation. Some do not have mesophyll in distinct palisade and spongy layers. Some have guard shaped like dumbells Eudicot- leaves have netted venation Airspace in mesophyll permit the rapid diffusion of co2 into water and o2 Blue light triggers proton pumps located in the guard cell plasma membrane. Also the synthesis of malic acid and the hydrolysis of starch Protons are pumped out of the guard cells the protons are produced when malic acid ionizes. As protons leave the guard cell electrochemical gradient(charge of a concentration difference) forms on the two sides of the guard cell plasma membrane
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Electrochemical gradient drives the uptake of potassium ions through voltage-activated potassium channels into the guard cells. Chloride ions are also taken into the guard cells through ion channels osmotically active ions increase the solute concentration in the guard cell vacuoles. Resulting osmotic movement of water into the guard cells cause them to become turgid forming a pore. As potassium ions leave guard cells starch is hydrolized into starch which increases in
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This note was uploaded on 04/03/2008 for the course BIO 102 taught by Professor Brey during the Fall '08 term at Rutgers.

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bio final study - Leaves typically consist of a broad flat...

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