Study Guide Key Ch_38 43z6h

Chapter 38: Angiosperm Reproduction and Biotechnology Interactive Questions 38.1 a) stamen b) anther c) filament d) petal e) carpel f) stigma g) style h) ovary i) sepal j) receptacle k) ovule Pollen is formed in the anther. Pollination occurs when pollen lands on the stigma. Fertilization occurs within the embryo sac in the ovule.

38.2 a) a pollen grain with a patterned spore wall surrounding a generative cell (which will divide to form two sperm) and a tube cell. b) the embryo sac, often containing seven cells and eight nuclei. 38.3 Double fertilization conserves resources by allowing for nutrient development onl when fertilization has occurred. 38.4

a) seed coat b) epicotyl

c) hypocotyls d) cotyledons e) radicle f) cotyledon (scutellum) g) endosperm h) epicotyl i) hypocotyl j) radicle k) coleorhiza l) coleoptile

dicot

monocot 38.5 Hormonal interactions induce softening of the pulp, a change in color and an increase in sugar content. 38.6 The coleoptile pushes through the soil, and the shoot tip is protected as it grow up through the tubular sheath. 38.7 Apomixis provides for the dispesal of seeds which are clones of the parent plant. Suggested Answers to Structure Your Knowledge 1) One version of the life cycle of an angiosperm. See also textbook Figure 38.2

2) Sexual: Advantages include increased genetic variability, which provides the potential to adapt to changing conditions, and the dispersal and dormancy capabilities provided by seeds. Disadvantages are that the seeding stage is very vulnerable, sexual reproduction is very energy intensive (since most seeds and seedlings don’t survive), and genetic recombination may separate adaptive traits. Asexual: Advantages include the hardiness of vegetative propagation and the maintenance of genetically well-adapted plants in a given environment. Disadvantages relate to the advantages of sexual reproduction: There is no genetic variability from which to choose should conditions change, and there are no seeds for dormancy or dispersal. 3) Benefits: reduce use of chemical pesticides; weed crops with herbicides instead of erosion-producing tillage; increase nutritional value of crops; produce diseaseresistant crops. Dangers: introduce allergens into human foods; harm nontarget species with pesticides; create hybrid “superweeds” due to crop-to-weed transgene escape; produce other unanticipated harmful results that cannot be stopped once GMOs are released into the environment. Answers to Test Your Knowledge Fill in the Blanks:

1) ovary 2) sporophyte 3) monoecious 4) embryo sac 5) radicle 6) epicotyl 7) coleoptile 8) scion 9) protoplast 10) callus Multiple Choice: 1) A flower on a dioecious plant would be: E both c and d (incomplete and staminate or carpellate) pg. 773 2) Which of the following structures is haploid? A embryo sac pg. 772 (diagram) 3) The terminal cell of an early plant embryo: D divides to form the proembryo pg. 777 4) In angiosperm, the sperm are formed by: D mitosis in the pollen tube pg. 776 5) The endosperm: E is or does all the above pg. 777 6) A seed consists of: A an embryo, a seed coat, and a nutrient supply pg. 777-778 7) Which structure protects a bean shoot as it breaks through the soil? A hypocotyl hook pg. 778 8) Which of the following is a form of asexual vegetative reproduction? E all of the above pg. 781 9) Protoplast fusion: C can be used to form new plant species pg. 782 10) In the plant embryo, the suspensor: D is analogous to the umbilical cord in mammals pg. 778 11) Flower organs have evolved form modified: A leaves pg. 772 12) What does self-incompatibility provide for a plant? D a biochemical block to selffertilization so that cross-fertilization is assured pg. 775 13) Into what does a microspore develop in an angiosperm? E both a and b are correct ( the male gametophyte and a pollen grain) pg. 774 14) Many plants form clones that develop after shoots emerge from the same root system. What is an advantage of forming such clones? A provide a strong start for new plants pg. 781 15) Why did it take nearly 20 years for plant breeders to convert opaque-2 mutant maize (with higher levels of two essential amino acids) into a variety that had a more durable endosperm? C Traditional plant breeding using hybridization and artificial selection is a time-intensive process pg. 783 16) Which of the following is a technique being developed to reduce the threat of introduced genes for herbicide or insect resistance escaping to closely related weed species? E All of the above would reduce the risk of crop-to-weed transgene escape pg. 785-786