Bio - Chapter 35

Bio - Chapter 35 - Chapter 35 Transport in Plants 35.1 How...

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Chapter 35 – Transport in Plants 35.1 How do Plants take up water and solutes? o Water is essential for transporting solutes both upward and downward, for cooling the plant, and for developing the internal pressure that supports the plant body Water moves through a membrane by osmosis o Solute potential (osmotic potential) measure of the effect of dissolved solutes on the osmotic behavior of the solution Greater solute concentration of solution = more negative solute potential and greater the tendency of water to move into it from another solution of lower solute concentration o Osmosis is a passive process – no direct input of energy is required o Pressure potential (turgor pressure) – As water enters a plant cell due to its negative solute potential, the entry of more water is increasingly resisted. o Water potential = psi = sum of its negative solute potential and its positive pressure potential o Bulk flow – the movement of a solution due to difference in pressure potential between 2 parts of a plant In xylem – bulk flow is between regions of differing negative pressure potential(tension) In phloem – it’s between regions of differing positive pressure potential (turgidity) Aquaporins facilitate the movement of water across membranes Aquaporins are membrane channel proteins through which water can move without interacting with the hydrophobic environment of the membrane’s phospholipid bilayer o Passive movement = one direction Uptake of mineral ions requires membrane transport proteins
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This note was uploaded on 04/17/2008 for the course BIO 1305 taught by Professor Eldridge during the Spring '08 term at Baylor.

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Bio - Chapter 35 - Chapter 35 Transport in Plants 35.1 How...

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