| A | B |
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| Why are leaves so important? | (1) They're the worlds' oldest solar energy collectors; (2) they're the world's most important manufacturers of food needed by all land animals. |
| What is the petiole? | Petiole = the stucture that attaches the leaf blade to the stem. |
| What is the difference between simple and compound leaves? | Simple: have only 1 blade and 1 petiole; compound have several blades, or leaflets, joined together and to the stem by several petioles. (Picture, 595) |
| What is the cuticle of the leaf and what does it do? | The cuticle = the waterfproof, waxy coating of the epidermal layer of most leaves. This decreases evaporation rates. (see pg. 503) |
| What are stomata? | Stomata = they are openings in the epidermis of leaves; through these openings water vapor and oxygen pass out of the leaf, and carbon dioxide passes into it. Stomata cut down the loss of moisture through evaporation, but a substantial amount of water is still lost to the outside through evaporation. Plants regulate opening & closing to blanace water loss with rates of photosynthesis. |
| What are guard cells? | These are specialized epidermal cells that control the opening & closing of the stomata by responding to changes in water pressure. By doing this, guard cells allow photosynthesis to take place and to prevent water loss. |
| What tissues form the veins in a leaf? | Xylem and phloem tissues gather in bundles that go out of the stem into the petiole; as these enter the leaf blade, they're surrounded by parenchyma and sclerenchyma cells. |
| What is leaf mesophyll? | In leaves, it's the layer of cells that contains chloroplasts and performs most of the plant's photosynthesis. |
| What is the palisade layer of mesophyll cells? | It's the layer of tall. column-shaped mesophyll cells just under the epidermal covering of the leaf. |
| What is the spongy mesophyll? | The spongy mesophyll = the layer of cells in leaves, arranged in a network with spaces between them, that connect with the stomata. There are many air spaces between them that permit carbon dioxide & oxygen to diffuse in and out of the leaf. |
| Explain cohesion, adhesion, and capillarity. | Water molecules are attracted to 1 another by a force called cohesion; they're attracted to other molecues by a force called adhesion; combined, these explain capillarity, which is the ability of water molecules to stick to one another & to the walls of a tube (pg. 505), |
| What is transpiration? | Transpiration is the evaporation of water from plant leaves. |
| What is transpiration pull? | Transpiration pull = the force that pulls water from the roots to the leaves as a result of the evaporation of water from leaves. As water evaporates, more is pulled up from the roots to replace what is lost. |
| In addition to transporting products of photosynthesis out of the leaves & down to stems and roots for storage or use, what functions do phloem perform? | (1) Move sugars from plants into their fruits; (2) food is pumped down to roots for winter storage; (3) in the spring, stored food is moved back to the trunk & branches through phloem; (3) phloem helps recycle extra phorphorus. |
| Know the pressure flow hypotesis. | See page 602. |
| How can angiosperms survive in deserts, ponds, on mountaintops, in salt water, in arctic regions, and in tropics? | They survive because through natural selection, the basic designs of their roots, stems, and leaves have evolved to make survival possible in each environment. |
| How have desert plants adapted to their severe conditions? | (1) They have very small leaf surfaces to limit water loss; (2) many have thick stems protected by waterproofing; (3) Some have roots that take water in quicklly after rainfall; (4) seeds can remain dormant for years until enough moisture arrives. (See pg. 598 for more info.) |
| What adaptation(s) appear in water plants, such as waterlilies, to help them survive? | Petioles have large open spaces that reach from their leaves down to the roots at the bottom; the open spaces fill with air through which oxygen can diffuse to the roots. |
| How do mangrove plants survive in saltwater environments? | The roots tolerate salt concentrations, and the leaves have special cells that pump salt out of the plant tissues and onto the leaf surfaces where it's washed off by rain. |
| In tropical forests, why do climbing plants survive better than nonclimbing ones? | Climbing plants have adaptations that permit them to climp up trees to reach sunlight. |
| Why have some plants developed specialized leaves that trap & digest insects? | This adaptation was necessary for plants in bogs where it's too wet & too acidic for bacteria of decay to survive. To get nutrients, especially nitrogen, the leaves evolved to trap needed nutrients. |
| Give examples of plants that eat animals or insects. | Venus' flytrap; pitcher plants; sundews; bladderworts. |
| Review: what is vascular cambium? | Vascular cambium is a meristematic area that produces vascular tissues and increases the thickness of stems over time. |
| What is capillary action? | It's the tendency of water to rise in a thin tube; the thinner the tube, the higher the water will rise inside it. |
| What is the major force in tansport inside a plant? | It is evaporation of water from leaves during transpiration. (see pg. 600) |
| What function does phloem perform relative to nutrients in a plant? | Phloem carries out seasonal movement of sugars within a plant. |
| What characteristics of leaves help them collect sunlight and carry out photosynthesis efficiently? | The flat, thin blades collect sunlight, and specialized cells in the leaf conduct photosynthesis & take in materials needed for that process. |
| How does wilting help a plant survive? | The stomata in the leaves close, so transpiration slows down, reducing the amount of water being lost by the plant. |
