CELL STRUCTURE & FUNCTION Ch. 7, Sec. 1-2 Pages 169-181 Section 7.1, Life is Cellular I. Discovery of the Cell A. Robert Hooke, 1665 - First to use a Compound Microscope to look at “cells.” 1. A compound microscope has two lenses. (Objective lens & Eyepiece) 2. Looked at a thin slice of cork which had many “little rooms.” B. Anton van Leeuwenhoek, 1674 – Used a simple microscope (one lens) to look at pond water. – He saw tiny living organism which he called “animalcules.” II. The Cell Theory A. What is a cell? - The basic unit of life. B. Schleiden & Schwann – German scientists who stated the cell theory: 1. All living things are made of cells. 2. Cells are the basic units of structure & function. 3. All cells are produced by existing cells. IV. Prokaryotes and Eukaryotes A. Prokaryotic Cells – Cells that do not contain a nucleus. – DNA is free to float inside the cell. – All bacteria are an example of prokaryotes. B. Eukaryotic Cells - Larger & more complex - Have a nucleus that contains the DNA - Have many “specialized” internal structures contained within a membrane - May live as single cells or make up multicellular organisms. Section 7.2 Eukaryotic Cell Structure I. Types of Eukaryotes. - Plant & Animal cells II. Organelles - Membrane-bound structures that act like individual organs. - Each carries out a specific function. III. Cytoplasm - Area between the nucleus and cell membrane. - Contains a fluid/jelly-like substance which allows easy movement of wastes and raw materials in and out of the cell. IV. Parts of a Eukaryotic Cell A. Nucleus 1. Contains all the DNA within a cell. 2. Surrounded by the “Nuclear Envelope.” - Membrane that protects the inside contents and also allows for the passage of materials in and out of the nucleus such as RNA. 3. Nucleolus - Center region of the nucleus where DNA is located and the production of ribosomes begins. 4. Chromatin - Form DNA is in when a cell is not dividing. - DNA wrapped around DNA. - “Looks like thin tangled/bound shoe laces.” 5. Chromosomes - Form DNA is in when a cell is dividing. - “Looks like single thick shoe laces” B. Ribosomes 1. Small grain-like particles of RNA inside the cytoplasm. 2. Located throughout the cell 3. Produce proteins from information within DNA. C. Endoplasmic Reticulum 1. System of passageways that transports proteins & other materials throughout the cell. 2. Two types of E.R. a. Rough E.R. - Is covered with ribosomes which produce proteins. b. Smooth E.R. - Mainly responsible for transportation and finishing the production of proteins. D. Golgi Body (Golgi Apparatus) 1. Proteins from the E.R. are transported here next. 2. Modifies, or packages proteins and other materials before they are secreted outside of the cell. - Puts the “finishing touches” on proteins. E. Lysosomes 1.Small organelles filled with digestive enzymes. - Break down food molecules that can be used by the cell as well as waste products. F. Vacuoles 1. Sac-like structures that store water, food and/or waste products. - Extremely important in water storage for plants. G. Mitochondria 1. Organelles that convert chemical energy stored in food particles into a more useful form. 2. Are enclosed by two membranes: a. Outer - Protects the inside of the mitochondria and allows materials to move in and out. b. Inner - Inside membrane where energy production occurs (ATP). H. Chloroplasts 1. Found only in plant cells. - Capture energy from sunlight and convert it into chemical energy in the process known as “PHOTOSYNTHESIS!” a. Creates “glucose.” I. Cell Barriers A. Cell Membrane - Found in plants, animals & bacteria. - Is a semipermeable lipid bilayer. - Controls what goes in and out of a cell. B. Cell Wall - Found in plants, algae, fungi & bacteria. - Provides support and protection to the cell. - Made mostly of the Carb. Cellulose. Cell Membrane Structure Cell Wall Cytoskeleton • Network of protein filaments that supports the shape of the cell and allows for movement throughout cell. – Composed of microfilaments and microtubules.