CHAPTER 38 : ANGIOSPERM REPRODUCTION AND

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CHAPTER 38 : ANGIOSPERM REPRODUCTION AND BIOTECHNOLOGY
I. Concept 38.1: Unique Features of the Angiosperm Life Cycle
A. Overview
• Diploid (2n) sporophytes produce _____________ by ________________; these grow into haploid (n)
______________________
• Gametophytes produce haploid (n) _________________ by ____________________; fertilization of gametes
produces a ____________________
• In _____________________, the sporophyte is the __________________ generation, the large plant that we see
• The gametophytes are ___________________ in size and depend on the _______________________ for
nutrients
• The angiosperm life cycle is characterized by “three Fs”: ____________________________________________
B. Flower Structure and Function
1. Flowers are the _____________________________ of the angiosperm sporophyte; they attach to a part of the
stem called the __________________________
• The receptacle or base is a modified _________________ end which holds the ___________________
2. Flowers consist of four floral organs: ________________________________________
3. ________________ are the green leaf-like floral parts which protect the flower in the ____________ stage
• All the sepals form the ____________________
4. __________________ are the conspicuous colored flower parts
• All the petals together form the ___________________
5. A ______________________ consists of a __________________ topped by an _____________________ with
pollen sacs that produce pollen (male)
6. A ___________________ has a long style with a ____________________ on which pollen may land (female)
7. At the base of the ___________________ is an __________________ containing one or more
_____________________ which develop into ________________ after fertilization
8. A single carpel or group of fused carpels is called a ___________________
9. _____________________ flowers contain all four floral organs
10.___________________ flowers lack one or more floral organs, for example _________________ or carpels
11.Clusters of flowers are called _______________________
C. Development of Male Gametophytes in Pollen Grains (Microsporogenesis)
• Within pollen sacs of an anther, diploid ____________________ undergo meiosis to form 4 haploid
_______________________
Microspore nucleus undergoes _____________________ to produce a generative cell and a tube cell
Wall of the microspore _____________________ and becomes sculptured into a species-specific pattern
The ______________ cell and __________________ cell are enclosed in the thickened wall to form the pollen
grain, an ____________________ male gametophyte
• Tube cell will form the ______________________ tube
• Generative cell forms ________________________ nuclei (mature male gametophyte)
D. Development of Female Gametophytes (Embryo Sacs) (Megasporogenesis)
• _______________________ in ovule grows and goes through ___________________ to form 4 haploid
megaspores (only 1 usually ____________________)
Remaining megaspore grows and its nucleus undergoes ___________ mitotic divisions, forming 1 large cell with
____________haploid nuclei
Membranes partition this into a ___________________ embryo sac
• Ovules form within ovary and contain the female gametophyte or ____________________
• At the end containing the egg is the ____________________ (an opening through the integuments surrounding
the embryo sac)
E. Pollination
• In angiosperms, _________________________ is the transfer of pollen from an anther to a stigma
• Pollination can be by wind, water, bee, moth and butterfly, fly, bird, bat, or water
• As pollen germinates, tube nucleus forms a _____________________ down the style toward the embryo sac
• At the same time, generative _____________________ divides by mitosis to form 2 sperm nuclei (male gamete)
• Pollen tube penetrates __________________
F. Double Fertilization
• After landing on a __________________ stigma, a pollen grain produces a pollen tube that extends between the
cells of the style toward the __________________
• __________________________ results from the discharge of two sperm from the pollen tube into the embryo
sac
• One sperm fertilizes the ___________________, and the other combines with the polar nuclei, giving rise to the
triploid (3n) food-storing _____________________
• After double fertilization, each ovule develops into a ___________________
• The ovary develops into a ___________________ enclosing the seed(s)
G. Seed Development, Form and Function
1. Endosperm Development
• _____________________ development usually precedes embryo development
• In most monocots and some eudicots, endosperm stores ___________________ that can be used by the
___________________
• In other eudicots, the food reserves of the endosperm are exported to the ____________________
2. Embryo Development
• The first mitotic division of the zygote is ____________________, splitting the fertilized egg into a basal cell and
a terminal cell
3. Structure of the Mature Seed
• The embryo and its food supply are enclosed by a hard, protective ___________________
• The seed enters a state of ____________________
• In some eudicots the embryo consists of the embryonic axis attached to ______________________ (seed
leaves)
• Below the cotyledons the embryonic axis is called the ___________________ and terminates in the
______________________ (embryonic root); above the cotyledons it is called the ___________________ (shoot
tip with a pair of miniature leaves)
• A monocot embryo has _________________________
• Grasses, such as maize and wheat, have a special cotyledon called a __________________________ which
absorbs nutrients from the endosperm during germination
• Two sheathes enclose the embryo of a grass seed: a _____________________ covering the young shoot and a
__________________ covering the young root
4. Seed Dormancy
• Seed dormancy increases the chances that ______________________ will occur at a time and place most
________________________ to the seedling
• The breaking of seed dormancy often requires ________________________ cues, such as
_____________________ or lighting changes
5.Seed Germination and Seedling Development
• Germination depends on ______________________, the uptake of water due to low water potential of the dry
seed
• The __________________ (embryonic root) emerges first
• Next, the ___________________ breaks through the soil surface
• In many eudicots, a hook forms in the ________________________, and growth pushes the hook above ground
• The ____________________ straightens and pulls the cotyledons and shoot tip up
• In maize and other grasses, which are monocots, the _________________________ pushes up through the soil
H. Fruit Form and Function
1. A _____________________ develops from the ovary
2. It protects the enclosed seeds and aids in _____________________ by wind or animals
3. A fruit may be classified as ___________________, if the ovary dries out at maturity, or ________________, if
the ovary becomes thick, soft, and sweet at maturity
4. Fruits are also classified by their development:
-_________________, a single or several fused carpels
-____________________, a single flower with multiple separate carpels
-______________________, a group of flowers called an inflorescence
5. An _______________________ fruit contains other floral parts in addition to ______________________
6. Fruit dispersal mechanisms include: ___________________________
II. Concept 38.2: Plants Reproduce Sexually, Asexually, or Both
A. Asexual reproduction, or vegetative reproduction, produces ________________________.
B. Mechanisms of Asexual Reproduction
1. ______________________ is an example in which pieces of the parent plant break off to form new
individuals that are exact genetic replicas of the parent.
2. ____________________ is the asexual production of seeds from a diploid cell. (Ex: dandelions)
C. _________________________ uses several techniques of artificial vegetative reproduction such as grafting,
growing clones from
cuttings, and test-tube cloning
D. Asexual reproduction can be ____________________ to a successful plant in a ______________ environment
E. Sexual reproduction generates ___________________________ that makes evolutionary adaptation possible
F. While some flowers ______________________, other have methods to _________________ self-fertilization
and ___________________ genetic variation.
• One of these is _________________________________, in which a plant _______________________ its
own pollen or that of a closely related plant, thus insuring ___________________________
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