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BIOL108 Lecture Notes - Lecture 23: Pollen Tube, Double Fertilization, Endosperm

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jadeworm291
3 Nov 2018
School
University of Alberta
Department
Biology (Biological Sciences)
Course
BIOL108
Professor
Cynthis Friedman

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BIOL108 Lecture Notes - Lecture 21: Wollemia, Araucaria Araucana, Ginkgoales

23

BIOL108 Lecture Notes - Lecture 23: Pollen Tube, Double Fertilization, Endosperm

24

BIOL108 Lecture Notes - Lecture 24: Meristem, Opisthokont, Unikont

Document Summary

The female gamethophyte develops within an ovule (megasporangium) contained within an ovary. A pollen grain on a stigma germinates and the pollen tube grows down to the ovary. Double fertilization occurs when the pollen tube discharges two sperm into the female gametophyte within an ovule. The other sperm initiates development of food-storing endosperm (sperm combines with two nuclei in the central cell of the female gametophyte) The triploid endosperm nourishes the developing embryo. Food store for seed (endosperm) develops only after fertilization double fertilization: developmentally-coordinated timing of the embryo and its food stores, no resources are wasted if egg is unfertilized (contrast even to gymnosperms) Female gametophyte reduced in size and hence cheaper to produce. Production of the small female gametophyte takes only a few days rather than months. Fruit (angios only!: fruit: mature ovary containing seeds. Flowers, e. g. , cauliflower broccoli: some crops are for oil, eg.

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Related Questions

1. A plant the lacks petals and has well-developed anthers ismost likely

pollinated by fruit-eatingmammals.
pollinated by bees.
pollinated by birds.

pollinated by wind.

2. SELECT EACH TYPE of tissue that may be found in a maturefruit or seed. Can be more than one

Diploid sporophyte tissue from theprevious generation
Triploid endosperm
Diploid embryonic tissue
Haploid sperm cells

Tissue from the female gametophyte

3. Based on the outcome for plants, a monkey eating a banana isa

parasite.
pollinator.
disperser.

fertilizer.

4. Select all of the environmentswhere seeds would be an advantage over spores. Can be more thanone

Deserts
Areas with unpredictablerainfall
Wet humid swamps
Open habitats with sparsevegetation

Under a dense forest canopy

5. Select all the advantages that seeds have over spores.

Seeds have increased droughtresistance.
Long term dormancy ispossible.
Sexual reproduction is onlypossible with seeds.
Nutrition is packaged with theembryo.

Widespread dispersal is possible with a seed coat.

6. Nectar is a sugar-laden liquid that is very energeticallyexpensive to produce. Why do plants allocate resources to produceit instead of just producing more flowers?

Nectar serves as an enticement forinsects.
Nectar is sticky and traps windborne pollen.
Nectar provides nutrition to thedeveloping embryo.

Nectar provides energy during pollen tube formation.

7.The dried pericarp that forms the peanut shell provideevidence that peanuts are

legumes.
drupes.
samaras.

pomes.


8. All members of the Anthophyta have

nectaries.
animal pollinators.
scented flowers.
ovules enclosed in carpels.

fleshy fruits for dispersal.

9. Why is external water not essential for fertilization in seedplants?

Ovules are contained within thepollen.
Sperm cells are used to transportpollen to the archegonia.
Seed plants use pollen instead ofsperm for fertilization.
The sperm cells in seed plants arecapable of resisting desiccation.

Pollen grains are transported by wind or an animal.

10.Select the true statements concerning seeds. Can be more thanone

Seeds allow for dormancy untilfavorable conditions arise.
The fruit provides nutrition to thedeveloping embryo.
The ovule dries and forms the seedcoat.
The seed stores all of thenutrition and water the embryo needs to germinate.
Seeds can resist conditions thatwould kill a live plant.

Seeds are key to wide dispersal of offspring.

11. Select the true statements concerning sperm and pollen. Canbe more than one.

In seed plants the entire malegametophyte is dispersed.
The pollen fertilizes the egg.
The pollen tube facilitates thepollination of the ovule.
Pollen transports the cells thatform the sperm but only the sperm fertilizes the egg.

Unlike mosses and ferns water is not needed for fertilization inseed plants.

12.Check which of the following are correct regarding thebenefit of seeds. Can be more than one.

Seeds protect the young embryo byenclosing it in several layers of gametophyte tissue.
Seeds provide a source ofnourishment to the embryonic plant.
The integument forms a seed coatthat protects against desiccation.
Seeds provide a structure in whicha dormant embryo can avoid unfavorable growing conditions andgerminate when conditions improve.

Seeds are a means to transport offspring away from the parentalplant.

13. A fruit-bearing dioecious flower would have

a gynoecium.
neither an androecium nor agynoecium.
an androecium.

both an androecium and a gynoecium.

14. A researcher brings a sample of dry soil to the lab, wetsit, provides ample amounts of fertilizer, and places the soil in acontainer in a greenhouse. Which type of plant would be leastlikely to emerge?

Corn
Sunflower
Liverwort
Wheat
Pine seedling

Question 1

The key innovation that allowed for plant survival on land, seenin the first land plants and all others after, but not in thecharophytes, is

Question 1 options:

fruit.

vascular tissue.

the seed.

protection of the embryo.

Question 2

Which dramatic change in the alternation-of-generations lifecycle led to the protection of all phases of the life cycle and theformation of seeds?

Question 2 options:

transition from a dominant gametophyte generation to a dominantsporophyte generation

transition from a dominant sporophyte generation to a dominantgametophyte generation

Question 3

Which structure(s) allow the sporophyte of vascular plants to beprotected against drying out?

Question 3 options:

the waxy covering of leaves, called the cuticle

small openings in the leaves, called stomata

guard cells that surround each stoma

all of these structures protect the dominant sporophyte fromdrying out

Question 4

Why are the bryophytes called nonvascular plants?

Question 4 options:

because they are specialized for transporting water and organicnutrients

because their roots, stems, and leaves lack vascular tissue

because they protect their embryo

because they produce wind-blown spores

Question 5

Which generation is dominant in the bryophytes?

Question 5 options:

the generations are equally dominant

the sporophyte

the gametophyte

there is no sporophyte generation in bryophytes

Question 6

Which of the bryophytes are typically low-lying, due mostly totheir need for moisture and lack of vascular tissue?

Question 6 options:

the mosses

the liverworts

the hornworts

all of the bryophytes are low-lying

Question 7

Which structure of the moss protects the embryo from dryingout?

Question 7 options:

the archegonium

the antheridium

the sporangium

the stalk

Question 8

Cooksonia were the first __________ plants; they hadwind-blown spores, __________, leaves, and roots.

Question 8 options:

nonvascular; branches

vascular; seeds

nonvascular; seeds

vascular; branches

Question 9

The roots of today's lycophytes are much like __________ were inearly vascular plants; the vascular tissue is __________.

Question 9 options:

roots; centrally placed

stems; centrally placed

leaves; only found at the perimeter

branches; only found at the perimeter

Question 10

Pteridophytes, or ferns and their allies, are __________vascular plants with __________.

Question 10 options:

seed-producing; microphylls

seedless; microphylls

seedless; megaphylls

seed-producing; megaphylls

Question 11

Microphylls __________. Megaphylls__________.

Question 11 options:

are found in all vascular plants; are only found in thelycophytes

are broad leaves with a single strand of vascular tissue; arenarrow and have several strands vascular tissue

are broad leaves with several strands of vascular tissue; arenarrow and have a single strand of vascular tissue

are narrow and have a single strand of vascular tissue; arebroad leaves with several strands of vascular tissue

Question 12

The fern life cycle

Question 12 options:

all of these choices accurately describe the fern lifecycle.

is dependent on external water.

relies on the wind to disperse the spores.

produces a gametophyte that lacks vascular tissue.

Question 13

Seed plants use meiosis to produce

Question 13 options:

spores and pollen.

seeds and fruit.

pollen and seeds.

microspores and megaspores.

Question 14

In seed plants, a microspore develops into

Question 14 options:

an egg.

a pollen grain.

a sporophyte.

All of these answers correctly complete this sentence.

Question 15

Within the angiosperms, or ___________, two groups exist. Theyare named for their __________.

Question 15 options:

vascular plants; number of cotyledons, or seed coats

nonvascular plants; leaf type

flowering plants; number of cotyledons, or seed coats

fungi; leaf type

Question 16

The __________ parts of a flower are the stamens, each of whichhas two parts: the anther and the filament. The __________ parts ofa flower are the carpel, which has three major regions: the stigma,the style, and the __________.

Question 16 options:

female; male; ovary

male; female; sepals

female; male; sepals

male; female; ovary

Question 17

Double fertilization during the angiosperm life cycle involvestwo sperm, one of which __________, while the other __________.

Question 17 options:

fertilizes the egg to form a zygote; produces the endospermnucleus, which will develop into food for the developing plant

is a mature male gametophyte; is an immature malegametophyte

lands on the carpel of the plant; is usually blown away in thewind

develops into the seed; develops into the fruit that surroundsthe seeds

Question 18

The bodies of most fungi are made up of a network of filamentscalled hyphae.

Question 18 options:

True

False

Question 19

What is the difference between land fungi and the chytrids?

Question 19 options:

Land fungi are motile and have flagella at all stages of theirlife cycle. The chytrids do not have flagella.

Land fungi are nonmotile and do not have flagella at any stageof their life cycle. The chytrids have flagellated spores andgametes.

Land fungi are nonmotile and only have flagellated spores. Thechytrids have flagellated spores and gametes.

Both are motile for part of their life cycle. Land fungi aremotile as gametes. Chytrids are motile as spores.

Question 20

The vast majority of described species of fungi are __________fungi, which include unicellular __________, which reproducesexually once their food supply runs out. When yeast ferment, theyproduce ethanol and carbon dioxide.

Question 20 options:

zygospore; black bread molds

club; mushroom

sac; yeast

mutualistic; lichen