BIO 1030 Lecture 10: BIO 1030 Lecture 10
12 Feb 2017
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Document Summary
Bacteria, archaea, and plants have cell walls. Plant cell walls: primary cell walls. Wall stretches when the cell is growing. Reason why trees can grow so tall: secondary cell walls (some plant cells) Plant cells connected by numerous channels that pass through the cell walls. For exchange of water and small solutes between cells. Exterior cell surfaces in animals: no cell wall, extracellular matrix (ecm) Sturdy but flexible sheets on cells: tight junctions. Cells of tissues that serve as barriers: gap junctions. Allow cells to communicate through plasma membrane channels. Lend strength while allowing small molecules and ions to pass through. Energy: the capacity to do work, our biosphere gets its energy from the sun, two basic forms of energy. Two forms are converted back and forth. Potential energy is stored of position or configuration. Measuring energy: food energy is measured in calories, calorie.
