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Dante Matero
Dr. Teague, AP Bio
4/14/11
Chapter 38 Summary
-Angiosperm (flowering plants) sometimes trick insects into pollinating off of them
through the use of sexually-luring chemicals
- Most important plant in most environments
I. Flowers, Double fertilization, and fruits are unique features of the angiosperm life cycle
-Life Cycles characterized by an alternation of generations
- Multicellular haploid and diploid take turns
-Fertilization: fusion of gametes results in diploid zygotes
-The Three F’s (key derived traits of the angiosperm life cycles): flowers, double
fertilization, and fruits
A. Flower Structure and Function
1. Flower organs: sepals, petals, stamen and carpels are attached to the
receptacle
a. stamens/carpels: reproductive
b. sepals/petals: sterile
2. Anther- terminal structure of the stamen
3. ovary-base of carpel
4. slender neck of carpel-style
5. stigma- sticky structure at the top of style
6. pistil- single carpel or grouped ones
7. Complete Flowers have all organs
8. Incomplete Flowers do not have all organs
9. Inflorescenses: showy flower clusters
10. Development of male Gametophytes in Pollen Grains
a. microspores- formed by microsporocyte meiosis
b. pollen grain- two cells plus a spore wall
c. pollen tube- a long, cellular protuberance that delivers sperm to
the female gametophyte
11. Development of Female Gametophytes (Embryo Sacs)
a. dmbryo sac- female gametophyte
i. fifteen variations
b. entire process happens within carpel’s ovary
i. produces four haploid megaspores; only one survives
ii. undergoes a complicated process which results in the
ovule consisting of embryo sac and two surrounding
integuments
12. Pollination
a. defined as being the transfer of pollen from a single angiosperm
to a stigma
i. accomplished by wind, water or animals
ii. wind- enormous amounts of pollen are in the air, due to
the randomness of the wind
iii. water- aquatic plants
iv. animals- moths, birds, bats, etc.
B. Double Fertilization
1. Endosperm- food-storing tissue of the seed
2. Double Fertilization- the union of two sperm cells with different nuclei
of the female gametophyte
C. Seed Development, Form, and Function
1. Endosperm Development
a. liquid mass (endosperm) is formed by a division of the ovules
i. they eventually form walls
2. Embryo Development
a. first mitotic zygote division splits the egg into a basal and
terminal
b. suspensor- anchors embryo to parent plant
3. Structure
a. dormancy- is defined as being the stopping of the process of
growing; the metabolism also ceases
b. seed coat- can cause dormancy
c. hypocotyl: embryonic axis
d. dicle: embryonic root
e. epitocyl: where cotylodons are attached
f. coleophile: covers young shoots
g. colerhiza: covers young roots
4. Germination and Development
a. imbibition: uptake of water due to low water potential
i. causes germination
ii. causes seed to expand
D. Fruit Form/Function
1. Fruit- protects the enclosed seeds
2. Simple Fruits: fruits that are derived from a single carpel or several
fused carpels
3. Aggregate Fruit: results from a single flower that has amore than one
separate carpel, each forming a small fruit
a. FRUITLETS!
4. Multiple Fruit- develops from an inflorescense
5. Accessory Fruits: what we commonly call the fruit
II. Flowering plants reproduce sexually, asexually or both
-
asexual reproduction occurs when offspring are derived from a single parent
w/o genetic recombination
A. Mechanisms of Asexual LReproduction
1. Fragmentation: separation of a parent plant into parts that develop into
whole plants
2. apomixes: asexual production of seeds
B. Advantages and Disadvantages of Asexual Versus Sexual Reproduction
1. Vegetative Reproduction: asexual reproduction in plants
2. Can happen very often in vegetables
3. Sexual can increase genetic diversity
4. Asexual cannot
C. Mechanisms That Prevent Self-Fertilization
1. Dioecious: plants cannot self fertilize because different individuals
have either staminate flowers or carpellate flowers
2. Self-Incompatibility- anti-selfing mechanism where plants reject own
pollen
3. Plant does not recognize its own pollen
D. Vegetative Propagation and Agriculture
1. Clones from Cuttings
a. callus forms- undifferentiated cells
b. Some can be cloned from single leaves
2. Grafting
a. stock: plant that provides the root systerm
b. scion: twig grafted onto the stock
3. Test tube cloning and related techniques
a. test tube plantlets can be transferred to soil and lead normal lives
b. transgenic: genetically modified organisms that have been
engineered to express a gene from another species
c. protoplast fusion: tissue culture methods to invent new plant
varieties that can be cloned
III. Humans Modify Crops by breeding and genetic engineering
A. Plant Breeding
1. People see an important trait and cross it with a domesticated species
2. Most breeders cross pollinate plants of a single species but some rely on
hybridization between two different species
B. Plant biotechnology and genetic engineering
- in the last two decades, genetic engineering has become a powerful force
1. Reducing world Hunger and Malnutrition
a. Bigger crop yields are needed to feed bigger populations
b. must use transgenic crops to fulfill requirements
c. children need golden rice to prevent blindness
2. Reducing Fossil Fuel Dependency
a. biofuels: would drastically reduce the emissions of greenhouse
gases
C. Plant Biotechnology Debate
1. Many biologists are concerned abou the lasting effects of this GM food
2. Issues of Human Health
a. may transfer allergens
3. Possible effects on nontarget organisms
a. ex: caterpillars died after eating GM plants meant for butterflies
4. Addressing the problem of transgene escape
a. Worried about the possibility of the introduced genes escaping
from a transgenic crop into related weeds through crop to weed
hybridization
Relation to Topics in Chapter One
Chapter 38 related to Chapter 1 because it utilizes information like species and
genuses to help convey its information about GM plants. Chapter One gives much
information on hypotheses and If-Then thinking, and Chapter 38 certainly uses a lot of
this mentality when it tries to figure out the dangers of transgenic plants, different
pollination types, and the effects of GM food on humans. It uses the idea of Order to talk
about the different types of plants and their physical makeup. And it also tries to relate
the idea of evolution—that plants have been changing over these many years.