Chapter 7 – Cell Structure and Function 7.1 Life is Cellular

7.1 Life is Cellular The Discovery of the Cell Exploring the Cell Prokaryotes and Eukaryotes

The Discovery of the Cell Early Microscopes, 1660s Robert Hooke used an early compound microscope to observe a thin slice of cork, a plant material. made of thousands of tiny chambers called cells Anton van Leeuwenhoek used a single lens microscope to observe pond water and other things He discovered cells to be everywhere.

The Cell Theory a fundamental concept of biology All living things are composed of cells. Cells are the basic units of structure and function in living things. New cells are produced from existing cells. All cells contain genetic information.

Exploring the Cell/ Types of Microscopes Biologists still use the microscope to explore cells, however microscopes of today are much more powerful. Fluorescent labeling and light microscopy: enables moving molecules to be followed through the cell. Confocal light microscopy: scans cells with a laser beam creating 3-D images High-resolution video technology: produce movies of cells Electron microscopes: Transmission electron microscopes (TEMs): make it possible to explore cell structures and large proteins. Scanning electron microscopes (SEMs): a pencillike beam of electrons is scanned over the surface of the specimen.

Prokaryotes and Eukaryotes Cells fall into two broad categories depending on whether or not they have a nucleus. Nucleus: a large membrane-enclosed structure that contains the cell’s genetic material in the form of DNA. Membrane: a thin layer of material that serves as a covering or lining. Eukaryotes: cells that contain nuclei Prokaryotes: cells that do not contain nuclei.

Prokaryotes Generally smaller and simpler than eukaryotes. They have genetic material that is not contained in a nucleus. Carry out every activity associated with living things. They grow, reproduce, respond to the environment, and some move. This group includes bacteria.

Eukaryotes Larger and more complex then prokaryotes. Generally contain dozens of structures and internal membranes that are highly specialized. Contain a nucleus in which their genetic material is separated from the rest of the cell. Make up plants, animals, fungi, and protists.