Chapter 3 – Part 1 Cell Organelles The Cell Theory 1. 2. 3. 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. Organelles Organelles - “Little organs” in a cell Cytoplasm Cytoplasm - The portion of the cell outside the nucleus (jelly like material) Nucleus Nucleus - Contains nearly all the cell's DNA (genetic information) Sends orders to the organelles (the boss). Nuclear Envelope Nuclear Envelope - Layer of two membranes that surrounds the nucleus of a cell Dotted with thousands of nuclear pores, which allow material to move into and out of the nucleus (such as DNA or proteins) Nucleolus Nucleolus - Small, dense region within most nuclei in which the assembly of proteins begins Chromatin & Chromosomes Chromatin - granular material visible within the nucleus; consists of DNA tightly coiled around proteins Chromosome - Threadlike structure within the nucleus containing the genetic information that is passed from one generation of cells to the next When a cell divides chromatin condenses to form chromosomes Ribosomes Ribosomes – Where proteins are assembled Are small particles of RNA and protein found throughout the cytoplasm Like a small machine in a factory that produces proteins Endoplasmic Reticulum Endoplasmic Reticulum (ER) - Internal membrane system in cells in which lipid components of the cell membrane are assembled and some proteins are modified Rough Endoplasmic Reticulum Rough ER- The portion of the ER involved in the synthesis of proteins Given this name because of the ribosomes found on its surface. Abundant in cells that produce large amounts of protein for export. Smooth Endoplasmic Reticulum Smooth ER – Endoplasmic reticulum where ribosomes are not found on its surface Contains collections of enzymes that perform specialized tasks including: 1. 2. synthesis of membrane lipids detoxification of drugs Golgi Apparatus Golgi Apparatus - Modify, sort, and package proteins and other materials from the endoplasmic reticulum for storage in the cell or secretion outside the cell. Finishing touches are put on proteins before they are ready to leave the “factory.” Lysosomes Lysosomes - Cell organelle filled with enzymes needed to break down certain materials in the cell Functions: Digestion of lipids, carbohydrates, and proteins into small molecules that can be used by the cell Breaking down organelles that have outlived their usefulness Vacuoles Vacuoles – Sac like structure that stores materials such as water, salts, proteins, and carbohydrates. Plants contain large vacuoles Mitochondria Mitochondria - Organelles that convert the chemical energy stored in food into compounds that are more convenient for the cell to use. Chloroplasts Chloroplasts - Organelles that capture the energy from sunlight and convert it into chemical energy in a process called photosynthesis. Like a solar power plant. Contain the green pigment chlorophyll. Centrioles Centrioles – Direct the formation of the mitotic spindle in cell division Rod-shaped bodies that lie at right angles to each other Lie close to the nucleus Paired Cytoskeleton Cytoskeleton Network of protein filaments within some cells that helps the cell maintain its shape and is involved in many forms of cell movement Cytoskeleton Continued Examples of Cytoskeleton 1. Microfilaments - Threadlike structures made of a protein called actin Used for support and movement Cytoskeleton Continued Examples of Cytoskeleton 2. Microtubules - Hollow structures made up of proteins known as tubulins; help maintain shape and used to separate chromosomes in cell division Centrioles - Structure located in the cytoplasm of animal cells near the nucleus and help to organize cell division. Also help to build projections from the cell surface, which are known as cilia and flagella Enable cells to swim rapidly through liquids Cell Membrane Cell Membrane - Thin, flexible barrier around a cell; regulates what enters and leaves the cell Cell Wall Cell Wall - Strong supporting layer around the cell membrane in plants, algae, and some bacteria Most are made from fibers of carbohydrate (cellulose) and protein Cell Specialization Cell Specialization - Separate roles for each type of cell in multi-cellular organisms Cells throughout an organism can develop in different ways to perform different tasks. What is the organelle labeled #9? What is the organelle labeled #5? What is the organelle labeled #6? What is the organelle labeled #14? What is the organelle labeled # 2?