Actin

Cell Structure Chapter 4 Biology 1406 Fall 2013 Copyright ? The McGraw-Hill Companies, Inc. Permission required for reproduction or display. ? 2011 Pearson Education, Inc. Overview: The Fundamental Units of Life ? All organisms are composed of cells ? The cell is the simplest collection of matter that can be alive ? Cells arise only from pre- existing cells ? Though usually too small to be seen by the unaided eye, cells can be complex ? 2011 Pearson Education, Inc. 10 m 1 m 0.1 m 1 cm 1 mm 100 ?m 10 ?m 1 ?m 100 nm 10 nm 1 nm 0.1 nm Atoms Small molecules Lipids Proteins Ribosomes Viruses Smallest bacteria Mitochondrion Most bacteria Nucleus Most plant and animal cells Human egg Frog egg Chicken egg Length of some nerve and muscle cells