![]() Depending on the plant, the epidermis may have hairs, or trichomes, that extend out from the plant. They are often called pavement cells because they are flat like tiles or puzzle pieces. Epidermis cells typically have few if any chloroplasts. It is normally only one cell thick, but in some cases the epidermis can be a few cells thick. The epidermis is the outermost layer of cells in the plant. Trichomes extending from the surface of a leaf. Cutin is absent or greatly reduced in root tissue because roots need to reach out into the soil to absorb water and nutrients.Ī cluster of mite eggs just beneath the epidermis of a leaf. This coating helps limit the loss to the atmosphere of water that is inside the plant. In the shoot, the epidermis cells, which are the main cell type in dermal tissue, secrete a water-resistant substance called cutin (a waxy polymer), which coats the wall of the cell exposed to the environment. The cells making up dermal tissues are tough so that they can protect against mechanical challenges to the plant, like abrasion. Dermal tissueĭermal tissues (derma is Greek for “skin”) are on the outside of the plant and provide protection for the plant cells they surround. We’re going to look at three types of tissues: dermal, cortex, and vascular. The cells within a tissue may differ from one another, but they all contribute to a particular function. ![]() Watch this video about plant tissues (6:30)Ī tissue is a group of cells that share a function. What happens in the mitochondria, and what is the connection between that function in mitochondria and the function of chloroplasts?.Could this involve the mortar that holds cells together? What is the mortar that holds cells together? If lettuce is grown in a soil with low calcium content, the outer edges of leaves can degenerate and die, causing tip burn.What is the difference in function between the cell wall and the cell membrane?.Plant cells have other parts as well, but these are the key ones to know and understand now. If bricks in a wall are like cells in a plant, the middle lamella in the plant is like the mortar between bricks in the wall. Middle lamellaĪ material containing pectin that forms between cells and cements the cell wall of one cell to the cell wall of an adjacent cell. The fluid inside the cell membrane in which the organelles and other plant cell parts are suspended. The vacuole takes up much of the cell volume and gives shape to the cell. ![]() VacuoleĪn organelle containing various fluids, ions, chemical energy, and waste products from the cell. Chromosomes are the hereditary material passed on to new cells and to subsequent generations. Chromosomes contain the genetic material (deoxyribonucleic acid DNA) that is carried within each cell and that directs which chemical reactions are turned on and off in the cell. NucleusĪn organelle that contains the chromosomes. This metabolism is known as respiration and uses oxygen to convert sugars (and other carbohydrates) to energy and carbon dioxide. The mitochondria is where stored sugars from photosynthesis are metabolized to produce forms of energy that the plant can use for growth. A plant cell in the leaf blade will have many chloroplasts, while cells in the middle of the stem will have few or none. Chloroplasts are not evenly distributed throughout the plant but, as you might expect, are concentrated in parts of the plant that are exposed to and oriented toward the sun. In the chloroplast, light energy is captured and the first steps are taken in the chemical pathway that converts the energy in light into forms of energy that the plant can transport and store, like sugar and starch. ChloroplastĪn organelle (“organelle” is the generic name for a plant organ) that contains chlorophyll. If the cell were like a bicycle tire, the cell wall would be the thick, protective outer tire tread and the cell membrane would be the inner tube. ![]() The cell membrane is semi-permeable - it allows select compounds in and out, but blocks other types of compounds. The cell membrane is made up of layers of protein and lipid (fats and oils are examples of lipids). The cell wall protects the parts inside, and the cellulose molecules in the wall provide the support and rigidity needed to maintain the cell’s three-dimensional structure. The outer covering of the cell, the cell wall is a rigid membrane that contains cellulose (a carbohydrate that is indigestible for humans). The graphic below illustrates the key parts of the plant cell. Watch this video about plant cell parts (7:47) Summarize the key functions of those tissues.List the types of tissues in a plant and describe where they are located and the specialized cells that make up each of these tissues.By the end of this lesson you will be able to:
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