General Biology 2 Chapter 39

Explain the process of fertilization and embryo development in angiosperms

1. haploid microspores produced in the anthers by meiosis develop into pollen, the immature male gametophyte. 2. pollination occurs when a compatible pollen grain lands on a stigma. 3. pollen tubes grow through the style to the ovary, in which the ovules that contain the haploid female gametophytes 4. sperm cells fertilize egg and a central cell in one ovule. this double fertilization produces a zygote form the egg and nutritive endosperm from the central cell. 5. each ovule develops into a seed and the ovary develops into fruit fruit aids seed dispersal. 6. seed germinates and the embryo grows into a new sporophyte.

Compare the structure of a blastocyst in animals with that of a developing plant embryo. Discuss what the structure and function of the different cell "types"

Both have the cell mass, and both have a main nutrition source

Explain the unique nature, need, and function of the callose plugs in the pollen tube

Callose plugs concentrate the cytoplasm at the tip to maintain turgor pressure

Distinguish between complete, incomplete, perfect and imperfect flowers

Complete flowers - all 4 whorls Incomplete flowers - lack 1 or more whorls Perfect flowers - have stamens and carpels Imperfect flowers: Producing carpels - carpellate or pistillate Producing stamens - staminate

Some plants are dioecious and others are monoecious. Explain

Dioecious - staminate and pistillate flowers on different plants Monoecious - staminate and pistillate flowers on same plant

Explain if a developing angiosperm embryo is a gametophyte or a sporophyte

Embryo is a young, multicellular, diploid sporophyte Embryos depend on food supplied by sporophyte

Distinguish between eudicots and monocots based on their number of petals

Eudicot flower organs often occur in fours or fives or their multiples Monocot flower organs often occur in threes or multiples of three

The female gametophyte consist of seven cells. Where do all of these cells come? Are they all the same? Do they have different functions?

Female gametophyte consists of seven cell (eight nuclei), one of which is the egg cell

Present the control of flower development

Flower development is controlled by both environmental signals and changes in gene expression

Explain how a seed relates to a fruit. What is a fruit? Where to fruits come from? What part of the plant is a fruit? What are the functions of fruit?

Fruit is a structure that encloses and helps disperse seeds Dispersal helps reduce competition and allows colonization of new sites Fruits develop from ovary and sometimes other parts Ovary wall changes into a fruit wall (pericarp)

Explain who and when seeds germinate? What controls seed germination. When occurs when a seed germinates?

Germination occurs if seed encounters favorable conditions Embryo absorbs water, becomes metabolically active, and grows out of seed coat

Compare and contrast megaspores and mircospores

Meiosis produces diploid megaspores (no meiosis II) Diploid cells within the sporangium undergo meiosis producing 4 tiny haploid spores (microspores) each

Contrast the sporophyte and gametophyte generations in mosses and angiosperms

Moss- Sporophytes small and dependent on gametophyte Flowering plant- Sporophyte larger and independent while dependent gametophyte few-celled and contained within flowers

Distinguish between mature and immature male gameotphytes

Pollen grains are immature male gametophytes At the time of dispersal, the pollen grain is a two- or three-celled male gametophyte produced by mitotic division During a later phase of development, a mature male gametophyte produces sperm cells immature- microspore is in the immature pollen grain, isn't a gamete. Meiosis makes it haploid. Two cells. One is germinative cell and the other is the tube cell. mature- Lands on top of pistil and tries to recognize if its too related or not. Stimulates pollen grain to divide again by mitosis and the "sperm" is produced, makes it mature.

Explain what a seed is, where they develop, their structure, and their function

Seeds develop from fertilized ovules Seed contains embryo and endosperm

Give the four organs within most flowers and the function of each

Sepals- Often function to protect unopened flower bud Petals- Usually serve in attraction of pollinators Stamens and carpels (pistil)- Produce distinctive spores by meiosis

Identify the parts of a flower's pistil and stamen. Know the function of each

Stamens: stigma- sticky portion at the top of the style where pollen grains usually land style- the narrow elongated part of the pistil between the ovary and the stigma, grows pollen tube ovary- contains ovules After fertilization, the ovary swells to produce fruit pistil: anther- produces male gametes (pollen) filament- upports anther to make it accessible to insects

Endosperm is good for me. Explain

Supplies nutritional needs for developing embryo and often seedling Rich in protein, lipid, carbohydrate, vitamins and minerals

Compare the cleavage stage of development in animals with what occurs in plant embryogenesis.

both stages are going through cleavage. It is the two cell stage, The first time a plant cell divides they are different. They are the same in animals.

Present the relationship between carpels and the pistil. What are carpels and what are their functions

carpels- Vase-shaped structures that produce, enclose, and nurture female gametophytes pistil- Flower contains one or more carpels that form a pistil

Present the organization of the various parts of a flower including the carpels and stamens

carpels- innermost part of a flower. It is usually surrounded by male reproductive structures called stamens, both of which are surrounded by petals stamens- The main function of the stamen is to produce the pollen grains, which house male gametes, or sex cells, necessary for reproduction. filament holds up the anther.

Give the location and function of the ovule.

enclosed in integuments spore-producing structure

Follow the development of the male and female gametophyes

male- Pollen grain (microspore) transferred to the stigma of the flower develops into male gametophyte. Its nucleus divides to form a vegetative nucleus (tube nucleus) and a generative nucleus. This division takes place even before the pollen reaching the stigma. The division results in two unequal cells. female- The megaspore is the first cell of the female gametophyte. The lowermost megaspore enlarges and produces an embryo sac. In all angiosperms, development of female gametophyte is endosporous, i.e. within the megaspore. In typical case, the functional lowermost megaspore gives rise to 8-nucleate embryo sac. Out of these eight nuclei, the uppermost 3-nuclei towards the micropyle form egg apparatus containing middle egg cell and on its either side, two synergies

Distinguish between monocarpic and syncarpic flowers

monocarpic- flowering only once and then dying syncarpic- having the carpels of the gynoecium united in a compound ovary

Discuss pollen dispersal

pollen is dispersed through pollination: from wind from bugs self-pollination

Give the function of sporopollenin

pollen wall composed of mostly sporopollenin (physical strength, chemical inertness, and resistance to microbial attack)

Present the parts of the carpel

stigma, style, and ovary. The stigma is where pollination occurs. The style is a tube connecting the stigma to the ovary, which contains a chamber called a locule.

Present... The umbilical cord is to the development mammal as the ________________ is to the developing female gametophyes. Explain

suspensor in a plant= umbilical cord in mammals.

Present how and where pollen is produced. Explain what is inside a grain of pollen and the function of each. Know the function of a pollen grain

the stamen Produces male gametophyte and foster their early development Filament topped by anther Anther is a group of 4 sporangia which produce spores Diploid cells within the sporangium undergo meiosis producing 4 tiny haploid spores (microspores) each Immature pollen grains (male gametophye) develop from the microspore by mitosis