Actin – a globular protein that links into chains, two of which twist helically about each other, forming microfilaments, one of the three major components of the cytoskeleton, in muscle and other contractile elements in cells. This protein is only found in all eukaryotic cells, which an exception being nematode sperm. It can be present at concentrations of over 100 nanometers. It also forms thin filaments, which are part of the contractile in muscle cells. Actin helps in many processes throughout cells, including muscle contractions, cell motility, cell division and cytokinesis, vesicle and organelle movement, cell signaling, and the maintenance of cell junctions or cell shape. In vertebrates, there are three main groups of actin isoforms: alpha, found in muscle tissues, beta, and gamma, which are both found as components as components of the cytoskeleton and as helpers of internal cell motility.
Autotrophs – an organism that obtains organic food molecules without eating other organisms or substances derived from other organisms. It synthesizes its own organic substances from inorganic compounds. Some of these include sugars, lipids, amino acids and ammonia. There are two types of autotrophs: Photosynthetic and Chemosynthetic. Photosynthetic autotrophs use light to obtain energy while chemosynthetic organisms use compounds like hydrogen sulfide to obtain energy.
Cellulose –a structural polysaccharide of cell walls, consisting of glucose monomers joined by beta-1 and 4-glycosidic linkages. They are linear chain structures that can pack fibers of great tensile strength. It is naturally abundant; some examples of its composition include 90% of cotton and 50% of wood. Mammals can’t digest cellulose, but bacteria in cattle and other animals can break down cellulose.
Endosperm – a nutrient rich tissue formed by the union of a sperms cell with two polar nuclei during double fertilization, which provides nourishment to the developing embryo in angiosperm seeds. It requires the fusion of one nucleus from the embryo sac, and one from the pollen grain. In some seeds, endosperm have been completely absorbed at maturity, but in others, some is present until germination. This nutrient is in the form of starch, but it can also contain oils and protein.
Gametophyte – In organisms undergoing alteration of generations, the multi-cellular haploid form that mitotically produces haploid gametes that unite and grow into the sporophyte generations. Each of its cells has only one, unpaired set of chromosomes, as opposed to the diploid form of the organism. A gametophyte develops from spores produced by the sporophyte. Also, the gametophytes, of homosporous plants are bisexual, while heterosporous plants (seed plants) are unisexual.
Lignin – a hard material embedded in the cellulose matrix of vascular plant cell walls that functions as an important adaptation for support in terrestrial species. It is also a highly polymerized and complex chemical compound especially common in woody plants. The cellulose walls of the wood become filled with lignin, which is called lignifications. This increases the strength and hardness of the cell and gives the necessary rigidity to the tree. Global production of lignin is around 1.1 million tons per year.
Meristem – A plant tissue that remains embryonic as long as the plant lives, which allows for indeterminate growth. This part conducts cell division and cell growth. Apical Meristems found at the tips of stems and roots increase the length of these sections. Stems and roots may also grow in thickness or in diameter through cell divisions in lateral, or secondary. Some meristematic tissues include cork cambium, and intercalary Meristem. The apical Meristem also gives rise to organs like the leaves and flowers while the root apical Meristem dive rapidly and are considered to be indeterminate. Meristems are found in stem cells in animals.
Phloem – vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant. They are composed of several cells including sieve tube cells and phloem fibers. Sieve tubes provide the main channels in which food substances travel, and phloem fibers make up the soft fibers used commercially. (Flax seeds)
Sporophyte – in organisms undergoing alternation of generations, the multicellular diploid form that results from a union of gametes and that meiotically produces haploid spores that grow into the gametophyte generation. A sporophyte produces spores by meiosis. In flowering plants, the sporophyte comprises of the whole multi-cellular body except the pollen and the embryo sac.
Xylem – A vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from roots to the rest of the plant. This is also a transport tissue, but it is found in woody plants. It also helps provide support for the softer tissues by carrying water and nutrients up wards, away from the roots.
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Angiosperm – a flowering plant, also known as Angiospermae or Magnoliophyta, which forms seeds inside a protective chamber called an ovary. They can be distinguished from gymnosperms because they have flowers, endosperm within their seeds, and they produce fruit containing seeds. They have vascular plants that have the ovules and seeds that form the embryo and endosperm by double fertilization. Also, they typically have flower surrounded by a perianth composed of two sets of foral envelopes.
Conifer Leaf – This is leaf from a member of the largest gymnosperm phylum. Most conifers are cone bearing trees, like pines and firs. Conifer leaves are specialized photosynthetic organs. They are attached on the stem in a helical pattern, in opposite pairs, or in trios. Claw shaped and needle shaped leaves range from about one centimeter to 30 centimeters long.
Deciduous leaf – These are typically used in reference to trees or shrubs that lose their leaves seasonally, and to flowers that shed their petals seasonally. Deciduous means the dropping of a part that is no longer necessary or falling away after its purpose is complete. In temperate regions, many trees also lose their leaves (fall). These trees are present in deciduous forests.
Fruit (dry with seed) – A nut is a simple dry fruit with only one seed in which the ovary wall becomes very hard at maturity, and where the seed remains attached or fused with the ovary wall. Most nuts come from the pistils with inferior ovaries.
Fruit (fleshy with seed) – In simple fleshy fruits, the pericarp is juicy when they are fully ripe. There are two types of fleshy fruits: Baccate and Drupaceous. Baccates bear berries, while drupaceous usually are one seeded fleshy fruit with thin skin and a central stone containing a seed.
Pollen – Pollen is tiny, varies in shape and structure, is formed in the stamens of seed plants, and contains the micro-gametophytes of seed plants, which produce male gametes. Pollen grains have hard coats that protect the sperm cells during the process of their movement between the stamens to the pistil of the flowering plants or coniferous plants. When the pollen lands on a compatible pistil of a flowering plant, it will germinate and produce a pollen tube that transfers the sperm to the ovary.
Pollinator –A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization (syngamy) of the female gamete in the ovule of the flower by the male gamete from the pollen grain.
Pteridophyte – This is any plant of the division Pteridophyta, reproducing by spores and having vascular tissue, roots, stems, and leaves. They produce neither seeds nor flowers: they reproduce only through spores. Some examples of these types of plants include ferns, mosses, horsetails, and quillwort.
Stem (woody) – woody stems occur in plants which have been growing for two years or more. After two years, a plant’s stem thickens to accommodate growth and increased circulation in a plant. Trees are special woody stems and have other parts that other woody stemmed plants don’t have. It’s uncommon for woody stems to start out as a bush or plant and eventually grow into a tree
Thorn of a plant- Thorns are hard structures with sharp, pointed ends. They are modified versions of different plant organs, stems, stipules, leaf veins, or hair. They also function as a defense from predators.
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