Bcsc 513-521

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Plants live in two difference environments at the same time: *
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air - stem and leaves, surrounded by air and where light, CO2, and oxygen. *
soil - roots, supplies water and nutrients.
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Each part of the plant has a specific function:
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leaves - carry out photosynthesis.
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roots - anchor the plant & absorb water and soil nutrients.
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stems - support the leaves and transport materials to other plant parts. *
What does the plant use the glucose for? The plant uses sugars produced during photosynthesis to builts its structure. *
Petiole - the stalk that attaches the leaf to the stem.
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Covering the upper and lower surfaces of the leaf is a transparent layer of cells called the epidermis which forms a waterproof coating, the cuticle. *
Substances enter and leave the leaf by two routes: veins and stomates. *
Photosynthesis occurs in the mesophyll cells that contain numerous chloroplasts. These mesophyll pile up to make granum. *
Water molecules are present in the air as water vapor, they are never as abundant in the air as they are in the leaf. Thus, the plant loses water as it diffuses into the air through the stomates. This water loss is known as transpiration. *

When plant cells have adequate supplies of water, the water eerts a pressure, known as trugor pressure, against the cell walls. This pressure supports the stem and leaves. IF MORE WATER IS LOST FROM A PLANT BY TRANSPIRATION THAN IS REPLACED THROUGH THE ROOTS, THE CELLS LOSE TURGOR PRESSURE. *

How can a plant conserve water and still allow CO2 to enter? Each stomate is surrounded by a pair of cells known as GUARD CELLS. *
Guard cells - when they fill with water, they bend outward. As they bend, the stomates open and co2 can diffuse into the plant. *
These plants known as succulents have tissue that are so juicy that water can be squeezed from them. Such as a cactus. *
Although the major...
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