bio213 week 6 chapter 30

What is a flower?

Unique angiosperm structure that is specialized for sexual reproduction

What do microspores undergo?

Mitosis to produce haploid gametes

What are sepals?

Base of flower

• usually green

• Encloses the flower before it opens

What are petals?

Brightly colored attachments that help with attracting pollinators

How is the megaspore produced?

By the megasporangium through meiosis

What are stamens?

Microsporophylls→ produce microspores that develop into pollen grains containing male gametophytes

• consists of filament and anther

What is a filament?

Stalk of the stamen

What is an anther?

Terminal sac of stamen that produces pollen

What are carpels?

Megasporophylls→ produce megaspores that give rise to female gametophytes

• container in which seeds are enclosed

• Distinguishes angiosperms from gymnosperms

What is the simplified process of gymnosperms?

1. Microspores form pollen

2. Megaspores form female gametophytes

3. Pollination occurs

4. Pollen tube grows

5. Fertilization

6. Seed forms

7. Seed germinates

What is a stigma?

Type of carpel that receives pollen

What is a style?

Structure that leads from stigma to base of carpel (ovary)

What is the ovary?

Contains one or more ovules

• contains a female gametophyte

• If fertilized, an ovule develops into a seed

What is a pistil?

Used to refer to a carpel or carpels

What is a fruit?

When the ovary matures into a fruit

• protect seeds and aid in dispersal

What is the receptacle?

Place where all parts of flower attach

What is the corolla?

All of the petals together

What is the perianth?

Petals and sepals together

What is a dry fruit?

Ovary that dries out at maturity

• develops attachments designed for dispersal

What is a fleshy fruit?

Outer layers of ovary turn fleshy

• invests animal dispersal by ingestion

What is the life cycle of an angiosperm?

1. In the megasporangium of each ovule, the megasporocyte divides by meiosis, producing 4 megaspores→ only 1 survives

2. Megaspore undergoes 3 mitotic divisions, producing a female gametophyte

3. In the anther of a stamen, each microsporangium contains microsporocytes→ microsporocytes divide by meiosis

4. Each pollen tube elongates through the style, when reaching an ovule→ discharges its two sperm

5. Double fertilization occurs→ one sperm fertilizes the egg, the other sperm fertilizes the central cell, forming the endosperm

6. The zygote develops into an embryo that is packaged along with a food into a seed

7. When a seed germinates, the embryo develops into a mature sporophyte

What is cross pollination?

The transfer of pollen from an anther of a flower to a stigma of a flower on another plant of the same species

• enhances genetic variability

What is a micropyle?

A pore in the integument of the ovule

• pollen tube penetrates through the micropyle and discharges 2 sperms, one forming a diploid zygote

What is double fertilization?

One fertilization event produces a zygote, and the other produces a triploid cell

What are cotyledons?

Zygote develops into a sporophyte embryo with a rudimentary root and 1 or two seed leaves

What is an endosperm?

A tissue developed from the triploid central cell

• rich in starch and other food reserves that nourish developing embryo

What are fungi?

Heterotrophs by absorption

• Secrete enzymes outside body

• Breakdown complex molecules

• Responsible for decomposition

• Without fungi, dead organic material would accumulate

What are the roles of fungi?

Decomposers→ breakdoen dead material

Parasites→ infecting plants

Mutualists→ help roots absorb nutrients

What are hyphae?

Long, thread-like filaments

• hyphae network form a mycelium

• Usually haploid

What is a mushroom?

Reproductive structure or fungi

What are mycelium?

Interwoven mass of hyphae

• Large surface area makes absorption efficient

• Main feeding structure of fungi

What is chitin?

Make up cell wall of fungi

• A polymer for fungi

• Makes up exoskeleton of crustaceans and insects

What are Septate hyphae?

Divided by cross walls by septa w/ pores

• Allows cell-cell movement of organelles

• Compartments w/ nuclei

What are coenocytic hyphae?

No septa, continuous cytoplasm

• Many nuclei throughout the mycelium

• Many contains hundreds/thousands of nuclei

What are haustoria?

Parasitic fungi that absorbs nutrients from plants

What are arbuscules?

Mutualistic fungi that lives attached to plant roots, grows into root

• Helps plant get nutrients

What are mycorrhizae?

Mutualistic fungi that provides water, minerals, phosphate

• Plant provides sugars

• Most vascular plants have mycorrhizae

What are ectomycorrhizal fungi?

Fungal hyphae surround root

• Don’t enter plant cells

• Exchange nutrients outside cells

What are arbuscules myccorhizal fungi?

Have hyphae that extend into root cell

• Form branching structures called arbuscules

• Direct nutrient exchange with plant

What are the properties of fungal reproduction?

Spores→ sexually or asexually

Spores disperse by wind, water, animals

How does asexual reproduction of fungi work?

Fungi hyphae (haploid) undergo mitosis to make spores→ spores grow into new hyphaea

How does yeast reproduce?

Through budding of asexual reproduction

• Cell develops an outgrowth, that detaches from main cell

What is plasmogamy?

1. Two hyphae (haploid) that are compatible fuse the cytoplasms

2. Undergo heterokaryotic stage→ new hyphae has 2 nuclei (n+n)

3. Undergoes karyogamy→ fusion of nuclei, diploid zygote forms (2n)

4. Zygote immediately undergoes meiosis to make spores

5. Spores germinate (inc number of hyphae) growing into myecelium

What are cryptomycetes and microsporidians?

30 known species

• Located in soils, aquatic environments

• Flagellated spores

• Cryptomycetes less understood

• Microsporidians are parasitic

What are chytrids?

1000 known species

• Located in lakes, soils, marine habitats

• Decomposers, parasites, mutualists

• Flagellated spores

• Can infect amphibian skin→ impacts gas water, and ion exchange

What are the ecological roles of enzymes?

• decomposers

• Mutualists

• Pathogens

• Critical for nutrient cycling

• Break down cellulose and lignin

What are lichens?

Symbiosis between fungus and algae/cyanobacteria

• fungus provides→ structure, protection, water retention

• Photosynthetic partner provides→ sugars

What are fruticose lichens?

Shrublike lichen

What are foliose lichens?

Leaflike lichens

What are crustose lichens?

Encrusting lichens

What is plant organization?

Cell→ tissue→ organ→ organ system

What is the shoot system?

Organs above ground

• leaves, stems

What is in the root system?

Organs below ground

• Roots

What are the function of roots?

• absorb water needed for photosynthesis

• Anchor the plant in soil

• Absorb minerals needed for growth

• Store water and food in some plants

What is the taproot system?

consists of one main vertical root, which develops from the primary rot

• facilitates the anchorage of the plant in the soil→ enable s plant to grow taller

• Lateral roots responsible for absorption

What is a fibrous root system?

Primary root dies early on→ many small roots emerge from stem

• considered adventitious→ grows in an unusual location

• Each root forms its own lateral roots, which form their own lateral roots

What are stems?

Hold leaves upright towards light

• move water, minerals, and sugars

What are root hairs?

Thin extensions of root cells

• increase surface area

• Absorb water and minerals

What is the purpose of leaves?

Takes CO2 from air

• release O2 to air

• Controlling water loss

• Capturing sunlight energy

What are buttress roots?

Aerial roots of tropical trees

• look like buttresses

• Give architectural support to trunks of trees

What are prop roots?

Aerial ,adventitious rots of corn

• support tall, top-heavy plants

What are the structures of a leaf?

• blade→ fat part of leaf

• Apex→ tip of leaf

• Margin→ edge of the blade

• Veins→ branching transport pathways in leaf

• Midrib→ main central vein

What are plant veins?

Clustered xylem and phloem bundles

What is the petiole?

Stalk attaching leaf to stem

What is the base?

Bottom part of leaf (near where it attaches)

What is the stipule of a leaf?

Small, leaf-like structure near base of petiole

What is a node of stem?

Where a leaf attaches

What is the internode of a stem?

Stem space between nodes

What is the apical bud?

Growth of a young shoot that is concentrated near the growing shoot tip

What is an axillary bud?

Upper angle (axil) formed by each leaf and stem

• can potentially form a lateral branch, thorn, or flower

What is a rhizome?

Horizontal shoot that grows just below surface

• vertical shoot emerge from axillary buds on rhizome

What is a stolon?

Horizontal shoot that grows along surface

• enable plant to reproduce asexually→ plantlets grow from axillary buds along each runner

What is a tuber?

Enlarged ends of rhizomes or stolons specialized for storing food

• eyes of potatoes are clusters of axillary buds

What are tendrils?

Typically modified leaves or stems that clings to a support structure

What structures protect buds?

bud scales that protect the terminal bud

• protected by leaf primordial

• Bud scales fall off and leave scars on twig

What are spines?

Leaves on plants designed for protection

What are storage leaves?

Bulbs that have a short underground stem

• modified leaves that store food

What are reproductive leaves?

Produces adventitious plantlets→ fall off the leaf and take root in soil

What is a leaf scar?

Where leaf fell off a tree

• bundle scars→ dots inside leaf scar that show xylem/phloem connections

What is dermal tissue?

Outer protective covering of plant

• first line of defense against physical damage and pathogens

• Deuces water loss

• Found on roots, stems leaves

What is an epidermis?

Single tissue in nonwoody plants that acts like the dermal tissue

What is the periderm?

Protective tissue in woody plants that replace epidermis in older regions of stems and roots

How does water and mineral enter roots?

Absorbed from soil through epidermis

What are the three tissue systems of a plant?

1. Dermal tissue

2. Ground tissue system

3. Vascular tissue system

What are guard cells?

specialized epidermal cells involved in gaseous exchange

• found in shoots

What are trichomes?

Highly specialized epidermal cell growths

• found in shoots

• Can reduce water loss and reflect excess light in desert species

• Defend against insects through shapes that hinder movement or glands that secretes sticky fluids or toxic compounds

What are ground tissues?

Makes up most of plant body

• photosynthesis

• Storage

• Support

• Found in roots, stems, and leaves

What is the stomata?

Pores for gas exchange

What is parenchyma?

Ground tissue

• thin cell walls

• Conduct photosynthesis, storage of food and water

• Found in leaves, stems, roots

What are collenchyma cells?

Cell walls that are unevenly thickened

• strong but flexible

• Provides flexible support, supports growing parts of plants without stopping growth

• Found in young stems, leaf stalks (stem connecting leaves to main stem)

• Almost like herbaceous stem

What are sclerenchyma?

Thick, rigid cell wals

• dead at maturity, very strong

• Function→ rigid support and protection

• Found in mature stems, seed coats, fibers and hard plant parts

What are the 3 ground tissues?

1. Parenchyma

2. Collenchyma

3. Sclerenchyma

What are vascular tissues?

Plant transport system

• tissue that move water, minerals, and nutrients

• Also supports plant

• Found in roots, stems, leaves

What is the xylem?

Moves water and mineral upwards (one-way flow)

• No end walls between cells (like a straw)