EXAM 3 MasteringBiology Chapter 41 – Flashcards
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In sexual reproduction of land plants, generations alternate between _____.
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making gametes and making spores
NOTE: this is why the two generations are called gametophyte and sporophyte.
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Female gametophytes in angiosperms are hidden, and protected. Where are they found, and what are they also called?
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They are inside the ovules, and they are called embryo sacs.
NOTE: The embryo sac contains the egg, or female gamete.
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What is one main function of sepals?
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Sepals protect the flower bud as the flower is developing.
NOTE: Sepals protect the bud from damage from insects and pathogens.
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Which of the following is a trait that both a megasporocyte and a microsporocyte share?
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Both are 2n and divide to form gametophytes.
NOTE: Both divide via meiosis to form haploid gametophytes
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The term __________ means that a cell has one set of chromosomes (n).
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haploid
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The term ___________ means that a cell has two sets of chromosomes (2n).
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diploid
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Angiosperms have two distinct forms: the _____(1)_____ and the _____(2)_____. The _____(3)_____ is highly reduced, consisting of only a few cells. The _____(4)_____ tends to be the larger and more obvious form.
Some of the cells in a _____(5)_____ undergo meiosis, producing _____(6)_____ that ultimately develop into _____(7)_____. Male and female gametophytes produce the sperm and egg that fuse, forming a _____(8)_____. This _____(8)_____ ultimately develops into the _____(9)_____, and the cycle repeats.
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(1) haploid gametophyte
(2) diplod sporophyte
(3) gametophyte
(4) sporophyte
(5) sporophyte
(6) spores
(7) haploid gametophytes
(8) diploid
(9) mature sporophyte
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___________ is a type of cell division in which a diploid cell divides and forms haploid cells.
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meiosis
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___________ is the transfer of pollen from the male reproductive structures to the female reproductive structures.
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pollination
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___________ refers to the fusion of gametes.
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fertilization
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___________ is a type of cell division in which the daughter cells are identical to the parent cells.
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mitosis
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The diploid ___________ develops into the sporophyte.
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embryo
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In the female gametophyte, the __________ is flanked by two cells that help attract the pollen tube.
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egg
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Meiosis occurs in the larger, _____(1)_____ , producing _____(2)_____ microspores and megaspores. These microspores and megaspores divide by _____(3)_____ and form the male and female _____(4)_____ , respectively. The male gametophyte is contained in a _____(5)_____ , which is carried to the female flower parts in a process called _____(6)_____. The female gametophyte is housed in the _____(7)_____ of the flower. Fertilization in the female gametophyte produces the _____(8)_____ (by fusion of sperm and egg). The zygote divides by _____(9)_____ , forming the _____(10)_____ that ultimately develops into an _____(11)_____ .
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(1) diploid sporophyte
(2) haploid
(3) mitosis
(4) gametophytes
(5) pollen grain
(6) pollination
(7) ovary
(8) diploid zygote
(9) mitosis
(10) embryo
(11) sporophyte
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What are two structures that are diploid in the angiosperm life cycle?
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zygote and embryo
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The zygote is produced by the fusion of a _____(1)_____ and a _____(2)_____ and is therefore diploid. The zygote divides by _____(3)_____, forming the _____(4)_____, which ultimately develops into the _____(1)_____ diploid _____(1)_____.
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(1) haploid sperm
(2) haploid egg
(3) mitosis
(4) diplod embryo
(5) mature
(6) sporophyte
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Double fertilization is a component of the angiosperm life cycle, and produces _____.
.
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the zygote and endosperm
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Double fertilization in angiosperms is most similar to ______.
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siblicide in sharks where one fetus will eat the other within the mother
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Which part of a plant attracts pollinators?
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petals
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Which process involves the transfer of pollen grains from an anther to a stigma?
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pollination
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True or false? The endosperm in a seed develops into the embryo.
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False, The endosperm in a seed is not the embryo, but the food supply for the embryo.
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Which term describes the male gametophytes of flowering plants?
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pollen tube
NOTE: The pollen tube is formed after a pollen grain is transferred to a receptive stigma and germinates, forming a tube that grows down through the style to the ovary of a flowering plant.
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How is fertilization in flowering plants different from fertilization in other plant groups?
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One sperm nucleus fuses with the egg to form a diploid zygote, whereas the other sperm nucleus fuses with two polar nuclei to form a cell that develops into endosperm.
NOTE: Angiosperms are unusual in that one sperm nucleus fuses with the egg and one sperm nucleus fuses with two polar nuclei to form a triploid cell that develops into a nutrient-rich tissue that nourishes the growing embryo.
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Which of the following statements about seed formation in a flowering plant is true?
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The swellings that develop into cotyledons are located at the end of the embryo on top of the row of single cells.
NOTE: The swellings that develop into cotyledons do indeed grow on top of the row of single cells produced by the basal cell.
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What is endosperm?
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via cotyledons, a source of food for the embryo
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Fruits evolved primarily as structures specialized to _____.
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DISPERSE SEEDS
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If seeds are dormant, the dormancy has to be broken before the seed can germinate. Which of the following is most likely to break seed dormancy?
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nicking or damaging the seed coat to allow water to penetrate the seed, thus hydrating cells inside the seed
NOTE; Hydration is an essential component of germination, and seed coat damage will permit water to enter the seed much more easily.
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Why do fruits change color when they ripen?
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Color change signifies that seeds are fully developed and ready for dispersal.
NOTE: Fruits are colorful to attract animal dispersers.
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Why are cotyledons green in beans but not in corn?
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Bean cotyledons are exposed to light.
NOTE: Because these cotyledons are above ground, they are able to be photosynthetic
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What is the major evolutionary trend in land plant life cycles?
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Sporophytes became larger and long lived while gametophytes became drastically reduced
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After successful pollination, a pollen grain produces a(n) __________ , a long filament that grows down the length of the style.
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pollen tube
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The __________ contains one or more ovules, which produce the female gametophytes
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ovary
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The nucleus of the _________ undergoes mitosis to form two sperm cells.
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generative cell
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The fusion of gametes results in a diploid _________.
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zygote
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The fusion of a sperm cell with the polar nuclei forms the _________.
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endosperm.
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Many aspects of the angiosperm life cycle make flowering plants particularly well-suited to life on land. In fact, angiosperms are the most diverse and widespread of all plants.
Which six of the following statements reflect angiosperm adaptations to life on land?
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(1) Flowers attract animal pollinators carrying pollen from other plants of the same species
(2) Fruits aid in the dispersal of seeds by wind or by animals that carry or eat the fruits.
(3) In many angiosperms, the male gametophyte contained in a pollen grain can be transported many miles away by wind or animal pollinators.
(4) Floral parts of the sporophyte protect the reduced female gametophyte from drying out and from UV radiation.
(5) Seeds protect and nourish plant embryos, and fruits protect the seeds.
(6) Seeds enable plant embryos to be dispersed long distances from the parent plant via wind or animals
