Biology-Ch.36 Response

Biology-Ch.36 Response - this move into the phloem and are...

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rences m transfers water, phloem transfers food m has companion cells m up, phloem down m is passive, phloem is active m is dead, phloem is alive Ch. 36 Response Chapter 36: Describe how xylem and phloem flow in an angiosperm. How are they similar? Different? Xylem is a primary vascular tissue composed of tracheids and vessel elements aligned linearly from roots to leaves in angiosperms and other vascular plants. Water enters the plant through the roots and enters the xylem. Elements of the xylem are dead at maturity and water flows up the stem by alternation of adhesion and cohesion. There is no active transport involved in this process. Water then reaches the leaves and is used to advance the process of photosynthesis. The products, photosynthates, of
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Unformatted text preview: this move into the phloem and are then transferred down the stem to the roots. Phloem consists of sieve tube cells and companion cells. Sieve tube cells are connected end to end to form a tube and transfer food via plasmodesmata between cells. These sieve tube cells are aided by the more metabolically active companion cells. Food moves, “loads”, into the phloem by way of active transport and then “unloads” into sugar sinks throughout the plant this same way. By transporting sugars into the phloem, the solute concentration raises causing water to move into the phloem (osmosis) and push the food down. o Similarities o Tubes that transfer stuff o Adaptations that allow for life on land o Water is important...
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This homework help was uploaded on 04/07/2008 for the course BIOL 152 taught by Professor Schnurr/vawter during the Spring '08 term at Wells.

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