chapter4 - Lecture Outline Animalcules and Cells Fill'd...

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Lecture Outline Animalcules and Cells Fill'd with Juices A. Early observations revealed an unseen world: 1. Galileo saw the facets of an insect's eyes. 2. Robert Hooke saw small compartments in cork, which he named cells. 3. Van Leeuwenhoek observed several types of living cells, including sperm. 4. Schleiden and Schwann proposed the idea that all living things were composed of cells. 5. Virchow concluded that all cells come from cells. B. These observations and many others led to the cell theory: 1. All organisms are composed of one or more cells. 2. The cell is the smallest unit having the properties of life. 3. The continuity of life arises directly from the growth and division of single cells. 4.1 Basic Aspects of Cell Structure and Function A. Structural Organization of Cells 1. A plasma membrane separates each cell from the environment, permits the flow of molecules across the membrane, and contains receptors that can affect the cell's activities. 2. A nucleus or nucleoid region localizes the hereditary material, which can be copied and read.
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3. The cytoplasm contains membrane systems, particles (including ribosomes), filaments (the cytoskeleton), and a semifluid substance. 4. There are basically two kinds of cells in nature: a. Eukaryotic cells contain distinctive arrays of organelles, including a membrane-bound nucleus. b. Prokaryotic cells (bacteria) have no nucleus. B. Organization of Cell Membranes 1. The lipid bilayer of plasma membranes forms a boundary between inside and outside of the cell, subdivides the cytoplasm into compartments, and regulates the entry/exit of substances. 2. Proteins positioned in the plasma membrane serve as channels, pumps, or receptors. C. Why Aren't All Cells Big? 1. Most cells are too small to be seen without a microscope. 2. The small size of cells permits efficient diffusion across the plasma membrane and within the cell. 3. As the surface area of a cell increases by the square of the diameter, the volume increases by the cube of the diameter. 4.2 Focus on Science : Microscopes--Gateways Cells 4.3 Defining Features of Eukaryotic Cells A. Major Cellular Components 1. The nucleus controls access to DNA and permits easier packing of DNA during cell division.
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2. The endoplasmic reticulum (ER) modifies proteins and is also involved with lipid synthesis. 3. Golgi bodies also modify proteins, sort and ship proteins, and play a role in the biology of lipids for secretion or internal use. 4. Various vesicles transport, store, and digest various materials within the cell. 5. Mitochondria have enzymes responsible for ATP formation. 6. Ribosomes , either "free" or attached to membranes are the assembly sites of polypeptide chains. 7.
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This note was uploaded on 10/23/2011 for the course BIOLOGY 10826265 taught by Professor Delcerro during the Spring '11 term at Thomas Jefferson School of Law.

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chapter4 - Lecture Outline Animalcules and Cells Fill'd...

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