b. Nastic movement
A plant's response to a stimulus such that the direction of the response is preprogrammed and not dependent of the direction of the stimulus
The phenomenon that occurs when individual molecules are so strongly attracted to each other that they tend to stay together, even when exposed to tension
Chemicals that circulate throughout multicellular organisms, regulating cellular processes by interacting with specifically targeted cells
n. Double fertilization
A fertilization process that requires two sperm to fuse with two other cells
2. Name the four processes for which plants require water. Which of these processes can be neglected for a short amount of time?
A plant uses water for photosynthesis, turgor pressure, hydrolysis, and transport. Since a plant can wilt without dying, turgor pressure can be ignored for a short time.
3. A biologist studies two plants. (flip)
The flowers of the first plant open each morning and close each night. The second plant's flowers stay open all of the time. However, if the plant is placed so that one of its sides is in the shade and the other is in the sunlight, the plant will eventually grow so that all of its leaves point towards the sunlight. Which plant is using nastic movement and which is using phototropism?
The first plant is using nastic movements and the second is using phototropism. Nastic movements refer to movements that happen in a pre-programmed direction. Phototropism is directional, depending on the direction of the stimulus.
4. Briefly describe the cohesion-tension theory of water transport in plants.
The cohesion-tension theory states that when water evaporates through the stomata in a plant's leaves, a deficit of water is created. This causes the water molecules just below those that evaporated to move up and take their place. Since water molecules like to stay together, however, the water
molecules just below the ones that moved up also move up, in order to stay close. This causes a chain reaction, eventually causing water from the roots to move up into other parts of the plant.
5. Do xylem cells need to be alive in order for xylem to do their job? Why or why not?
Xylem cells need not be alive for xylem to do their job. Since we think that the cohesion-tension theory of water explains how water and dissolved nutrients travel up a plant, the xylem cells need not play an active role in the transport.
6. Do phloem cells need to be alive in order for phloem to do their job? Why or why not?
Phloem cells must be alive in order for the phloem to do their job, because the phloem cells take an active part in translocation.
7. What substances do xylem contain? What substances do phloem contain?
Xylem contain water and dissolved minerals, while phloem contain sugar and organic substances.
8. Do insectivorous plants really eat insects? Why or why not?
Insectivorous plants do not really eat insects. They decompose the insects and use their raw materials for biosynthesis. Insectivorous plants produce their own food via photosynthesis just like other plants.
9. From a genetic point of view, what is the difference between vegetative reproduction and sexual reproduction in plants?
Vegetative reproduction leads to offspring with genetic codes which are identical to the parent. Sexual reproduction leads to offspring with genetic codes which are similar to, but not identical to, the parents' genetic codes.
10. A gardener says that one limb of his crabapple tree now produces normal-sized apples. What must the gardener have done to make this happen?
The gardener must have grafted limbs from a tree that produces normal-sized apples to his crabapple tree.
11. What is the male reproductive organ of a flower? What is the female reproductive organ?
The stamen is the male reproductive organ, and the carpel is the female reproductive organ. The carpel is sometimes called the pistil.
12. Why are the pollen grains and embryo sacs of flowers sometimes considered the gametophyte generation in an alternation of generations life cycle?
Both structures are multicellular, and they both reproduce using gametes. This is the basic definition of the gametophyte generation in an alternations of generation life cycle.
13. What two types of cells are found in a pollen grain?
There is at least one sperm cell, and there is a tube nucleus.
14. Typically, how many cells are in an embryo sac? How many of them get fertilized?
Typically, there are seven cells in an embryo sac. Remember, the megaspore undergoes mitosis three times to make eight nuclei. Then, the cell segments into six small cells and one large cell that has two nuclei. Two of these cells get fertilized. One becomes the zygote, and one becomes the endosperm.
15. Identify the structures in the figure
16. What structure is composed of parts a, b, and c from the drawing above?
Parts a, b, and c make up the carpel.
17. What structure is composed of parts f and g from the drawing above?
Parts f and g make up the stamen.
18. What is the difference between pollination and fertilization?
Pollination is simply the transfer of pollen from an anther to a stigma, while fertilization is the act of the sperms fusing with the egg and the large central nucleus in the embryo sac. You can use the terms "stamen" and "carpel" instead of "anther" and "stigma," but the latter are more precise.
19. How many sperm cells are used in plant fertilization?
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20. Where does the endosperm come from? What is its purpose?
The endosperm comes from the fertilization of the large, two-nucleus cell that is at the center of the embryo sac. It provides nutrition for the developing embryo.
21. The cotyledon or cotyledons help provide food for the plant before and often after germination. How do cotyledons accomplish each task?
Cotyledons either absorb the endosperm or aid in the transfer of nutrients from the endosperm to the embryo. This is how cotyledons provide a plant with nutrition before germination. After germination, they often perform the first photosynthesis in the plant.
22. Name the three basic parts of the plant embryo and what each gives rise to in germination.
The three basic parts are the radicle, the hypocotyl, and the epicotyl. The radicle becomes the root, the hypocotyl the stem, and the epicotyl gives rise to the first true leaves of the plant.
23. What is the purpose of a fruit?
A fruit allows for the dispersal of seeds to places away from the parent.
24. Name at least three ways in which pollen is transferred from the stamens of one flower to the carpel of another.
There are many possible answers. The student needs at least three: