A tree stands for hundreds of years, and its trunk never stops growing. How? In this course we learn how plants grow, which tissues give them strength and food, and how water travels from the root to the leaf.
3 lessons, about 1 h 15 min3 simulations10 problems6 practice questionsPython in every lesson
Created by StemPy LabA tissue is a group of similar cells that do one job together. Plants grow where their cells divide, in regions of meristematic tissue. The apical meristem makes the plant longer, the lateral meristem makes it thicker, and the intercalary meristem adds length at the base of leaves. New cells then differentiate into permanent tissue.
Simple permanent tissues are made of one kind of cell. Parenchyma is alive, with thin walls, and stores food. Collenchyma is alive, with walls thick at the corners, and gives flexibility. Sclerenchyma is dead, with walls hardened by lignin, and gives strength. The epidermis covers the plant and has stomata, and cork forms the protective bark.
Xylem and phloem are complex tissues that carry fluids. Xylem carries water and minerals up from the roots, and most of its cells are dead. Phloem carries food from the leaves to other parts, both up and down, and its cells are alive. Capillary action lifts water in thin tubes, but transpiration is the main pull in a tall tree.
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With Standard, you also open 3 more problems, 1 Python lab and 1 extra course. Everything you have used here stays free, always.