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CELL STRUCTURE PRESENTED BY: Melanie P. Guillermo, RPh  EUKARYOTIC CELL STRUCTURE NUCLEUS ❖ Contains the cell genome ❖ bounded by a membrane, which is composed of two lipid bilayer membranes DOWN SYNDROME EDWARD SYNDROME Tur...

CELL STRUCTURE PRESENTED BY: Melanie P. Guillermo, RPh  EUKARYOTIC CELL STRUCTURE NUCLEUS ❖ Contains the cell genome ❖ bounded by a membrane, which is composed of two lipid bilayer membranes DOWN SYNDROME EDWARD SYNDROME Turner’s  EUKARYOTIC CELL STRUCTURE NUCLEAR MEMBRANE ❖ exhibits selective permeability because of pores EUKARYOTIC CELL STRUCTURE NUCLEOLUS ❖ an area rich in RNA that is the site of ribosomal RNA synthesis Write a brief description here. Cytoplasmic Structures ❖ endoplasmic reticulum (ER) ❖ Golgi complex ❖ Plastids ❖ Lysosomes ❖ Peroxisome ❖ cytoskeleton Cytoplasmic Structures Endoplasmic reticulum (ER) is a network of membrane-bound channels continuous with the nuclear membrane ❑ Rough ❑ Smooth Cytoplasmic Structures Golgi complex consists of a stack of membranes that function in concert with the ER Cytoplasmic Structures Plastids ❑ Mitochondria ❑ Chloroplasts Cytoplasmic Structures Lysosomes are membrane enclosed vesicles that contain various digestive enzymes that the cell uses to digest macromolecules such as proteins, fats, and polysaccharides Cytoplasmic Structures ❖ Peroxisome is a membrane enclosed structure whose function is to produce H2O2 from the reduction of O2 by various hydrogen donors. Cytoplasmic Structures Cytoskeleton is a three-dimensional structure that fills the cytoplasm ❖ Microfilaments ❖ Intermediate filaments ❖ Microtubules Cytoplasmic Structures Cytoskeleton is a three-dimensional structure that fills the cytoplasm ❖ Microfilaments ❖ Intermediate filaments ❖ Microtubules  EUKARYOTIC CELL STRUCTURE CELL WALL SURFACE LAYER ❑ which may be composed of a polysaccharide such as cellulose or chitin or may be inorganic (eg, the silica wall of diatoms) MOTILITY ORGANELLES Flagella or Cilia PROKARYOTIC CELL STRUCTURE NUCLEOID ❑Prokaryotes have no true nuclei; instead they package their DNA in a structure known as the nucleoid. PROKARYOTIC CELL STRUCTURE CELL ENVELOPE ❑ protect the organisms from hostile environments, such as extreme osmolarity, harsh chemicals, and even antibiotics  PROKARYOTIC CELL STRUCTURE PLASMA MEMBRANE ❑ Also called bacterial cytoplasmic membrane BACTERIAL PLASMA MEMBRANE  FUNCTIONS of Cytoplasmic Membrane (1) selective permeability and transport of solutes; (2) electron transport and oxidative phosphorylation in aerobic species; (3) excretion of hydrolytic exoenzymes; (4) contain the enzymes and carrier molecules that function in the biosynthesis of DNA, cell wall polymers, and membrane lipids; and (5) bear the receptors and other proteins of the chemotactic and other sensory transduction systems.  Permeability and Transport A. Passive B. Active C. Group Translocation D. Special Transport Processes A: Passive Transport. This mechanism relies on diffusion, uses no energy, and operates only when the solute is at higher concentration outside than inside the cell. ❖ Simple Diffusion ❖ Facilitated diffusion ❖ Channel proteins form  B: Active Transport 1. Ion coupled transport systems move a molecule across the cell membrane at the expense of a previously established ion gradient such as proton or sodium motive force.  B: Active Transport 1. Ion coupled transport  B: Active Transport 1. Ion coupled transport  B: Active Transport 1. Ion coupled transport  B: Active Transport 2. ABC Transport This mechanism uses ATP directly to transport solutes into the cell  C: Group Translocation (vectorial metabolism) is not active transport because no concentration gradient is involved. D: Special Transport Processes. Iron (Fe) is an essential nutrient for the growth of almost all bacteria. Under anaerobic conditions, Fe is generally in the +2 oxidation state and soluble.  THE CELL WALL A. Peptidoglycan Layer three parts: 1. a backbone, composed of alternating Nacetylglucosamine and Nacetylmuramic acid connected by β1→4 linkages; 2. a set of identical tetrapeptide side chains attached to Nacetylmuramic acid; 3. a set of identical peptide crossbridges THE CELL WALL THE CELL WALL THE CELL WALL THE CELL WALL