Plant Reproduction and Flower Structure Quiz

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Questions and Answers

Which of the following describes asexual reproduction in plants?

Results in genetically identical progeny (correct)

Is less predictable in results

Produces genetically unique offspring

Requires two parents

In sexual reproduction, the offspring are genetically identical to their parents.

False

What is the primary function of the endosperm in seed development?

To provide nutrients to the developing embryo.

The male gametophyte is formed when a microspore divides by __________.

mitosis Signup and view all the answers

Match the following parts of a flower to their respective roles:

Sepals = Protect the flower bud Petals = Attract pollinators Stamens = Produce pollen Carpels = House the ovaries Signup and view all the answers

What type of fertilization occurs when one sperm cell fertilizes the egg and the other fertilizes the central cell?

Double fertilization Signup and view all the answers

In dicots, the endosperm is fully used up and nutrients are stored in the cotyledons.

True Signup and view all the answers

What are the three layers of the ovary that develop during fruit development?

Exocarp, mesocarp, endocarp Signup and view all the answers

What is the primary difference between dioecious and monoecious plants?

Dioecious plants have staminate and carpellate flowers on different plants. Signup and view all the answers

All flowers of monoecious plants are imperfect.

False Signup and view all the answers

What type of flower pollination leads to coevolution between flowers and their pollinators?

Animal pollination Signup and view all the answers

Flowers with both stamens and carpels are called ____________.

perfect Signup and view all the answers

Match the type of flower with its characteristics:

Actinomorphic = Radial symmetry, can be approached from any direction Zygomorphic = Bilateral symmetry, can be approached from one direction Wind-pollinated = Typically small, lacks perianth Animal-pollinated = Coevolution with pollinators present Signup and view all the answers

What mechanism prevents self-produced pollen from germinating on a stigma?

Chemical reactions at the stigma Signup and view all the answers

Self-pollination is a form of asexual reproduction.

False Signup and view all the answers

What are the two types of inflorescence based on flower opening order?

Determinate and Indeterminate Signup and view all the answers

Study Notes

Reproduction

Two types of reproduction in plants: sexual and asexual.
Sexual reproduction involves two parents and offspring are genetically unique.
Asexual reproduction involves a single parent and offspring are genetically identical to the parent.
Asexual reproduction is used in agriculture to produce consistent results.

Asexual Reproduction

Many plants can reproduce by fragmentation.

Sexual Reproduction

The sporophyte (2n) produces spores through meiosis.
There are two types of spores: megaspores (female) and microspores (male).
The gametophyte (1n) produces gametes through mitosis.
The female gamete is the egg and the male gamete is the sperm.

Flowers

Flowers are composed of four whorls: sepals, petals, stamens, and carpels.
A complete flower has all four whorls, while an incomplete flower lacks one or more whorls.

Sepals

Sepals are the outermost whorl of a flower.
They are typically green and protect the flower bud.

Petals

Petals are the second whorl of a flower.
They are often brightly colored to attract pollinators.

Stamens

Stamens are the third whorl of a flower.
They are the male reproductive organs and produce pollen.

Carpels

Carpels are the innermost whorl of a flower.
They are the female reproductive organs containing the ovary, style, and stigma.

Male Gametophyte Formation

Microspores divide by mitosis to produce a tube cell and a generative cell.
The generative cell divides again by mitosis to form two sperm cells.
When pollen lands on a stigma, it germinates.
The pollen tube grows through the style towards the ovary.
The sperm cells are carried down the pollen tube.

Female Gametophyte Formation

Megaspores divide by mitosis three times.
This produces eight nuclei.
The nuclei move around the large cell.
Three nuclei move to one end, three nuclei move to the other end, and two nuclei remain in the middle.
Walls form, now a mature gametophyte.
The mature female gametophyte contains two synergids, three antipodals, one egg, and one central cell containing two nuclei.

Double Fertilization

Double fertilization is a process unique to flowering plants.
One sperm cell fertilizes the egg to form a diploid zygote, which will develop into the embryo.
The other sperm cell fertilizes the central cell to form a triploid endosperm.
The endosperm grows quickly, the nuclei divide many times, and walls form later.

Embryo Development

The zygote divides by mitosis, forming an embryo proper and a suspensor.
Cotyledons form early. Monocots have one cotyledon and dicots have two cotyledons.
The embryo eventually takes on a cylindrical form.
The embryo consists of a radicle, hypocotyl, and epicotyl.

Embryo Development: Monocots

In monocots, the endosperm remains intact and feeds the embryo.
These seeds are called albuminous seeds.

Embryo Development: Dicots

In dicots, the cotyledons store nutrients.
The endosperm gets used up and its energy and resources are converted into the cotyledons.
These seeds are called exalbuminous seeds.

Fruit Development

The ovary develops three layers: exocarp (epicarp), mesocarp, and endocarp.
The fruit protects the seeds and helps to disperse them.
Simple fruits develop from a single ovary.
Aggregate fruits develop from separate carpels that fuse together.
Multiple fruits develop from all the carpels of an inflorescence fusing together.

Pollen Swapping

Cross-pollination occurs when pollen from another plant fertilizes the carpels.
Self-pollination occurs when pollen from the same plant fertilizes the carpels.
Self-pollination is not the same as asexual reproduction.
Many plants avoid selfing by various mechanisms, such as stigmas and anthers maturing at different times, compatibility barriers, and imperfect flowers.

Stamen/Style Maturation Times

If anthers and stigmas mature at different times, selfing is not possible.
In some species, the anthers mature first.

Stigma/Pollen Incompatibility

Chemical reactions at the stigma prevent self-produced pollen from germinating.

Flowering

Imperfect flowers lack either stamens or carpels.
Perfect flowers have both stamens and carpels.

Monoecious Plants

Monoecious plants have either perfect flowers or both staminate and carpellate flowers on the same plant.
This encourages cross-pollination but selfing is possible.
Examples of monoecious plants include cattails and corn.

Dioecious Plants

Dioecious plants have staminate and carpellate flowers on different plants.
All flowers are imperfect in dioecious plants.
Cross-pollination is necessary for reproduction in dioecious plants.
Examples of dioecious plants include dates, marijuana, and papaya.

Animal Pollinated Flowers

Animal-pollinated flowers have evolved to attract pollinators.
They often have specific features that attract specific pollinators.
Symmetry:
- Actinomorphic flowers (radial) have radial symmetry.
- Zygomorphic flowers (bilateral) have bilateral symmetry.

Wind Pollinated Flowers

Wind-pollinated flowers typically lack a perianth.
Zygomorphy is not beneficial for wind-pollinated flowers.
They are small flowers and produce large amounts of pollen.
Their stigmas are large and feathery to catch pollen.
They tend to grow in dense populations.

Ovary Location

Ovary location can be categorized into three types:
- Epigynous: Inferior ovary; perianth fused to the ovary wall.
- Hypogynous: Superior ovary; the ovary is clearly above the perianth.
- Perigynous: Semi-inferior; the perianth is fused along part of the ovary wall.
  
  Flower Number
  - A flower can be a single flower on a single pedicel.
  - Many flowers can be grouped or clustered together, known as an inflorescence.
    
    Inflorescences: Determinate
    - Inflorescences can be determinate or indeterminate.
    - In determinate inflorescences, the inflorescence apex is converted to a flower.
    - This limits the reproductive potential of the plant.
    - The terminal flower typically opens first.
    Inflorescences: Indeterminate
    - Indeterminate inflorescences have the lowest or outermost flowers open first.
    - New flowers continue to be produced throughout the season.
    - The main stem continues to grow.

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Description

Test your knowledge on the two types of plant reproduction: sexual and asexual. Explore the components of flowers and understand how they relate to reproduction. This quiz covers key concepts such as gametes, spores, and flower whorls.