692291
Descripción
Fichas por jennabarnes12387, actualizado hace más de 1 año
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Creado por jennabarnes12387
hace más de 10 años
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| Pregunta | Respuesta |
| All vascular plants produce what? | Seeds |
| What do seeds consist of. | The seed coat from the parent plant, the nutrition source that comes from the gametophyte and an embryo, the new tissue. |
| why are Conifer seeds described as naked? | they develop without protection |
| Phylum Coniferophyta includes? | cone bearing evergreen trees |
| Conifers are better developed for terrestrial growth as they don't need water for fertilization. What do they use instead? | they make microspores in the microgametophye which can be transfers to another tree to fertilize the megaspores in the megagametophyte. |
| describe the leaves or needles of a phylum Coniferophyta tree. | protected by a thick cuticle with sunken stomata below the surface, both of which help prevent water loss. |
| describe the stem of the coniferophyta tree. | they have specialized xylem cells called tracheids that are very effective for water conduction even in dry climates |
| the sporphytes in Conifers are? | heterospourous meaning more then one kind of spore is produced |
| What kind of cone are the mircospores produced in? what about the megaspores? | microspores are made in the staminate or pollen cones and megaspores are made in ovulate cones |
| why are staminate cones fround on the bottom of trees? wouldn't they spread farther is they were higher up? | if these cones were on the bottom, there would be a risk of the pollen fertilizing the megaspores from the same tree. if they are at the bottom of the tree this won't happen |
| this is a cross section of a pine needle or a pinus leaf. you can see the stomat that are belowt he surface to keep water in and the cuticle, here labled as the epidermis. in the middle of the cross section there are larger and smaller circles. These are the vascular bundles of xylem and phloem cells | |
| this is a pine wood maceration. the cell walls of the xylem are strangthened by lignin and are mostly tracheid xylem. You can see that the walls of the sample are thicker in some placesand thinner in others. these are called pits and they are so the water can flow through the pits and then the ends of the tracheids | |
| this is a staminate cone. the diploid cone is made of small reproductive sites called microsprophylls which contain microsporangia.these microsporangia make microspropcytes which hare the microspore mother cell. these microsporocytes divide through meiosis into 4 haploid microspores inside the microsporangia and then divide through mitosis into a microgametophyte AKA a pollen grain. the pollen grains will be released from the cone an dispersed by wind through pollination. | |
| this is a microgametophyte or a pollen grain. it consists of two air bladders on the dies a tube cell at bottom center and a generative cell top center | |
| this is a pine ovulate cone. It is made up of diploid ovuliferous scales on top of a sterile bract. inside each scale is a pair ovules. each ovule is made up the integument, a layer of cells that surrounds the megasporangium. inside the megasporangium is the megasporocyte or the megaspore mother cell. the megasporpcyte will eventually develop into a winged seed that will drop out of the cone when fertilized. at the end of the ovule is a small opening in the integuments called a micropyle. this is where the pollen sperm enters the megasporangium to fertilize the gametocyte. | |
| this is a pine ovule with mature archegonium. the megasporocyte will divide by meiosis to produce 4 haploid megaspores, only one of which will survive and be fertilized. this surviving megaspores will will divide through mitosis into a megagametophyte withing the megasporangium. these megagametophytes can have two or three archegonia which contain a single egg cell. | |
| what is the process of forming the female gametophyte called? | megagametogenesis |
| when a pollen cell enters the ovulate cone through a micropyle opening, the tube cell starts to grow a pollen tube that pushes through the megasporangium in to megagametophyte. while the tube grows the the generative cell divides in two, a sperm cell and a sterile cell. the sperm cell will divide again to make two non-flagellated sperm cells. the two sperm cells move through the pollen tube into a archegonium of the female gametophyte where one sperm will fertilize the egg cell and the other degenerates. | |
| Phylum Anthrophyta includes? | flowering or angiosperm plants that are vascular and produce seeds. |
| describe the strucutre of flowers. | the female and male parts are arranged in circle called whorls with female part in the center surrounded by the male parts. the reproductive parts are encircles by the petals and then the sepals |
| what are the three advanced structures developed by angiosperms that gymnosperms don't have? | flowers, double fertilization which is where two fertilization events occur to make a zygote as well as a nutritive tissue, and lastly the production of fruit. fruit is a matured ovary which protects the seeds and helps spread them |
| this is a lilac or syringia leaf. photosynthesis occurs in the palisade layer. the leaf is coverd not just by the epidermis but also a waxy cuticle, both helping to conserve water. the xylem tissue moves water up the stalk of the plant and into the leaves. | |
| this is a curcubita stem. the larger circles in the center are the xylem cells and the small are the phloem cells | |
| describe the details structure of a flower. | a flower is made up of reproductive stamens and carpels and sterile petals and sepals. the leave like sepals make up the outermost part of the flower called the calyx which is attached to the receptacle which attached the flower to the stalk or peduncle. the petals are above the sepals, the former encircling the stamens and carpels at the centre |
| this is a lilac anther. the anther is mounted on top of a thin stalk called a filament. the anther section contain 4 pollen sacs which are the diploid microsporangia. when a microspore develops into a pollen grain it will contain 2 nuclei. the structure of the pollen cell is similar to that of gymnosperms and will undergo mitosis to make the sperm nuclei. | |
| this is a lilac ovary. the ovary is found at the bottom of the carpal, below the style and the stigma, the later where the sperm enters the megasporangia. the egg sac or gametophyte is found at the tip of the swirl looking structures. these swirls are the integuments accessed through the micropyls. | |
| describe the process by which the embryo sac is formed. | a meagspore mothercell in each ovule goes through meiosis to make 4 haploid megaspores. three of these will degenerate and the remaining spore will undergo mitosis three times to make an embryo sac with 8 nuclei. |
| this is an embro sac. the 8 nuclei that have been produced are seen here. three of the 8 are found at the micropylar end or where the opening is, one finctioning as the egg the other two as synergid nuclei. three more are found at the opposite end and function as the antipodal nuclei. two nuclei stay in the centre as polar nuclei. the integuments will becomethe seed coat and surround the embryo sac leaving an opening at the micropyle. | |
| describe the process of double fertilization. | during fertilization, one sperm and one egg form a zygote, while the second sperm fuses with the polar nuclei in the center of the embryo sac. this fusion becomes the endosperm nucleus, made of three haploid cells so its 3n. this nucleus will divide repeatedly and act a a food source for the egg called the endosperm. |
| describe how fruit is produced. | the integuments of the ovule harden after fertilization into the seed coat. while the seed matures, the ovary that contains it forms into a fruit. this fruit will provide protection and help disperse the seed |
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