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Chapter 38 Reading Quiz 1.By what process do sporophytes make spores? 2.What are the two sterile parts of a flower? 3.What is the name of the food-storing.

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Presentation on theme: "Chapter 38 Reading Quiz 1.By what process do sporophytes make spores? 2.What are the two sterile parts of a flower? 3.What is the name of the food-storing."— Presentation transcript:

1 Chapter 38 Reading Quiz 1.By what process do sporophytes make spores? 2.What are the two sterile parts of a flower? 3.What is the name of the food-storing tissue of a seed? 4.Name one condition that could break seed dormancy. 5.In plants, what is asexual reproduction also known as?

2 1. Outline the angiosperm life cycle. Has alternation of generations Sporophyte is everything from zygote to mature plant Gametophyte is just pollen (sperm) & embryo sac (egg)


4 2. List the four floral parts in their order from outside to inside of the flower. Sepals green petal- like structures Petals colored structures Stamens male structures Carpels female structures

5 3. Distinguish between complete and incomplete flowers. Complete flowers those that have all four plant organs Incomplete flowers those lacking one or more of the four organs ex: grasses are incomplete (lack petals)

6 4. Distinguish between a perfect and imperfect flower. Perfect flower those equipped with both stamens and carpels (can still lack sepals or petals) Imperfect flower have only stamens or carpels (are always incomplete)

7 5. Distinguish between monoecious and dioecious. Monoecious if staminate & carpellate flowers are located on the same individual plant ex: corn Dioecious when staminate & carpellate flowers are on separate plants ex: date palms

8 6. Explain by which generation, structure, and process spores are produced. Generation sporophyte Structure within flower structure Process meiosis

9 7. Explain by which generation, structure and process gametes are produced. Generation gametophyte Structure within pollen & embryo sac structures Process mitosis

10 8. Describe the development of a pollen grain in angiosperms. Within the pollen sacs of the anther, the diploid cells undergo meiosis This forms 4 haploid microspores Each one divides once by mitosis and produces 2 cells (generative & tube) These 2 cells together constitute a pollen grain (an immature male gametophyte)


12 9. Of the pollen grain, distinguish among generative cell, tube cell, and sperm nucleus. Generative cell the half of the pollen grain that will form 2 sperm Tube cell when the pollen lands on the stigma of the carpel, the pollen tube begins to grow through to deliver the sperm to the egg Sperm nucleus the 2 sperm created by the generative cell

13 10. Describe the development of the embryo sac, and explain what happens to each of its cells. Embryo sac: 1. Antipodal cells (3) 2. Polar nuclei (2) 3. Egg (1) female gamete 4. Synergids (2) flank egg cell

14 11. Describe how pollen can be transferred between flowers. Pollen can be transferred by: 1. Wind 2. Insects 3. Birds

15 12. Describe mechanisms that prevent self- pollination, and explain how this contributes to genetic variation. Similar to immune response in animals 1.S-genes recognize self - if pollen & stigma have same alleles at S-locus, then pollen will not grow tube The incompatibility can happen at different locations - block inside pollen itself - response by carpels stigma


17 13. Outline double fertilization and describe function of endosperm. the pollen tube grows down the style toward the ovary The generative cell divides by mitosis and forms two sperm A chemical attractant draws the sperm to the ovary & discharges the two sperm One sperm fertilizes the egg to form the zygote The other combines with the 2 polar nuclei to form a triploid nucleus This gives rise to the endosperm, which stores food


19 14. Describe the development of a plant embryo from the first mitotic division to an embryonic plant with rudimentary organs. Endosperm development rich in nutrients Embryo development first division is transverse, splitting into basal & terminal cells Terminal gives rise to most of the embryo Basal becomes thread of cells to anchor the embryo & transfer nutrients Rudimentary cotyledons appear, and the embryo elongates, stem & root meristems begin to grow out


21 15. Draw a seed diagram and label and explain the following structures: a. seed coat b. embryo c. endospermd. cotyledons

22 16. Explain how a monocot and dicot seed differs. Monocot one cotyledon (seed leaf) for embryo nutrition Dicot two cotyledons for embryo nutrition

23 17. Describe several functions of fruit and explain how fruits form. Functions Enclose & protect seeds Aid in dispersal by wind or animals Formation Begins to develop after pollination triggers hormonal changes that cause the ovary to grow Pericarp is the thickened wall of the ovary (fruit)

24 18. Distinguish among simple, aggregate, and multiple fruits and give examples of each. Simple a fruit derived from a single ovary May be fleshy (cherry) or dry (soybean) Aggregate results from a single flower that has several carpels Blackberry, raspberry Multiple develops from an inflorescence (a group of flowers tightly clustered together) Pineapple

25 19. Explain how seed dormancy can be advantageous to a plant and describe some conditions for breaking dormancy. Seed dormancy very low metabolic rate & no growth or development Increases chance that seed will germinate at a time that is advantageous Conditions environmental Substantial rainfall Intense fire Extended exposure to cold Passage through an animals digestive tract

26 20. Explain how a seed mobilizes its food reserves and describe the function of aleurone, -amylase, and gibberellic acid. Once seed imbibes water, this triggers the seed to break its coat and begin digesting the food supply This happens because hormones called gibberellins (GA) signals the aleurone (thin outer layer of endosperm The aleurone synthesizes & secretes the digestive enzymes that hydrolyze the food The - amylase is the enzyme that hydrolyzes the food supply to make it available to the now developing seed


28 21. Describe variations in the process of germination including the fate of the radicle, shoot tip, hypocotyl, epicotyl, and cotyledons. Radicle the root of the embryo, emerges from the seed first Shoot tip breaks the soil surface Hypocotyl straightening of this pulls the shoot & cotyledons from the soil Epicotyl elongation and unhooking of this pulls new shoot & leaves to the surface Cotyledons some rise with the shoot (bean), some stay underground (pea)


30 22. Distinguish between sexual reproduction and vegetative reproduction. Sexual involves two different individual plants (one male, one female) - result in genetic variation Vegetative essentially a clone of a plant, reproduced through asexual means - possible due to indeterminate growth

31 23. Describe natural mechanisms of vegetative reproduction in plants including fragmentation and apomixes. Fragmentation the separation of a parent plant into parts that re-form whole plants (one of the most common types) Apomixes in dandelions and others - produce seeds without their flowers being fertilized - a diploid cell in the ovule gives rise to the embryo, and the ovules mature into seeds, which are dispersed

32 24. Describe various methods horticulturists use to vegetatively propagate plants from cuttings. Methods are based on the ability of plants to form adventitious roots or shoots Most houseplants & orchard trees are produced by cuttings At the cut end of a stem or shoot, a mass of dividing, undifferentiated cells called a callus forms, and the roots develop from this Grafting a cutting can be grafted onto another of a closely related species

33 25. Explain how the technique of plant tissue culture can be used to clone and genetically engineer plants. It is possible to grow whole plants by culturing even single parenchyma cells in an artificial medium with nutrients & hormones Can introduce foreign genes by firing DNA coated pellets into the cells

34 26. Describe the process of protoplast fusion and its potential agricultural impact. Protoplast fusion - being coupled with tissue culture methods - protoplasts are plant cells that have had their cell walls removed - can be screened for mutations & improve the agricultural value of the plant - could fuse two protoplasts that otherwise would be incompatible & produce a hybrid

35 Protoplasts

36 27. Define monoculture and list its benefits and risks. Monoculture the cultivation of large areas of land with a single plant variety Has helped farmers feed populations Fragile ecosystems; where there is little genetic variability, there is little adaptability

37 28. Define growth, morphogenesis, and cellular differentiation. Development the sum of all of the changes that progressively elaborate an organisms body Growth an irreversible increase in size, results from cell division and cell enlargement Morphogenesis accompanies growth; it is the development of form Cellular differentiation the acquisition of a cells specific structural and functional features

38 29. Describe how the plane of cell division is determined. The plane in which a cell will divide is determined during the late interphase The microtubules of the cytoskeleton rearrange The band that they form will be where the cell will divide

39 30. How is cellular differentiation controlled? Cellular differentiation is controlled by the genes Differentiation continues throughout the plants life Meristems sustain this indeterminate growth Differentiation reflects the synthesis of different proteins in different types of cells

40 31. Describe what pattern formation and positional information is. Pattern formation the development of specific structures in specific locations - a key element in the overall development of an organisms form Positional formation what pattern formation depends upon - signals of some kind that indicate each cells location within an embryonic structure, such as a root tip

41 32. Describe pattern formation in flower development. The transition of a vegetative shoot tip into a floral meristem Begins with a combination of environmental clues (daylength, hormones) The meristem identity genes are switched on The protein products of these genes are transcription factors that help to activate the genes required for development of the floral meristem Once induced to flower, positional info commits each part to become one plant organ

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