Cellular Biology
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Cellular Biology Chapter 1 1 Prokaryotes vs. Eukaryotes Prokaryotes Nucleus (single, circular chromosome) Cyanobacteria, bacteria, and rickettsiae Eukaryotes Complex cellular organization Membrane-bound organelles Well-defined nucleus Higher animals, plants, fungi, and protozoa 2 Mosby items and derived items © 2006 by Mosby, Inc. Cellular Functions Movement Conductivity Metabolic absorption Secretion Excretion Respiration Communication 3 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Cell Nucleus Nuclear envelope- Membrane around nucleus Nucleolus- organelles involved in cell division DNA- chemical blueprints of life DNA replication- semi conservative method, repair with nuclear enzymes in some cancers sometime defective repair enzymes, and transcription – making mRNA and tRNA and r RNA from DNA gene templates Histone proteins – bind to outside of DNA double helix and protect DNA as well as control what genes are expressed at what time. Cell division – mitosis – Prophase – metaphase – anaphase – telophase – interphase. Cell cycle 4 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Cell Nucleus 5 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Cell Cytoplasm Cytoplasmic matrix Cytosol Function Cytoplasmic organelles 6 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Cell Cytoplasm 7 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Ribosomes - organelles rRNA made from DNA and 2 protein subunits Free ribosomes – independent from reticulum Attached ribosomes associated with ER Endoplasmic reticulum – ER membrane complex inside cell Site of protein synthesis Smooth vs. rough endoplasmic reticulum 8 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Ribosomes involved with protein synthesis. Line up tRNA + aa, rRNA and mRNA with enzymes that attach aa’s into long polypetide strands Endoplasmic reticulum –site where ribosomes produce proteins Mosby items and derived items © 2006 by Mosby, Inc. 9 Eukaryotic Organelles Golgi complex – final processing site for proteins, especially those destined to be secreted from the cell. Flattened, smooth membranes Secretory vesicles Proteins from the endoplasmic reticulum are packaged in the Golgi complex Cisternae 10 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Golgi complex 11 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Golgi complex – usually associate with ER and outer cell membranes. Site of final processing of proteins to be secreted out of cell 12 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Lysosomes membrane bounded structures Originate from the Golgi and contain lytic enzymes Catalyze and breakdown proteins, lipids, nucleic acids, and carbohydrates Role in autodigestion Some vitamins can destabilize lysosome membranes (retin A anti wrinkle cream) and cortisone stabilizes membranes preventing cellular breakdown (part of antiinflamitory action Peroxisomes Contain oxidative enzymes Break substances down into harmless products Mosby items and derived items © 2006 by Mosby, Inc. 13 Eukaryotic Organelles Mitochondria Surrounded by a double lipid–bilayer membrane Participates in oxidative phosphorylation Increased inner membrane surface area provided by cristae Location where enzymes of the Krebs cycle are located and where ATP is produced in the Electro transport chain reactions 14 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Mitochondria 15 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Vaults Cytoplasmic ribonucleoproteins, shaped like octagonal barrels Cellular trucks 16 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Cytoskeleton “Bones and muscles” of the cell Maintains the cell’s shape and internal organization Permits movement of substances within the cell and movement of external projections Microtubules Centrioles Microfilaments 17 Mosby items and derived items © 2006 by Mosby, Inc. Eukaryotic Organelles Cytoskeleton 18 Mosby items and derived items © 2006 by Mosby, Inc. Plasma Membrane Controls the composition of a space or compartment they enclose Structure Caveolae Lipids Amphipathic lipids Hydrophilic and hydrophobic Phospholipids, glycolipids, and cholesterol Carbohydrates 19 Mosby items and derived items © 2006 by Mosby, Inc. Plasma Membrane 20 Mosby items and derived items © 2006 by Mosby, Inc. Plasma Membrane Proteins Integral, peripheral, transmembrane Functions Receptors Transport Enzymes Surface markers Adhesion molecules 21 Mosby items and derived items © 2006 by Mosby, Inc. Plasma Membrane Plasma membrane protein functions 22 Mosby items and derived items © 2006 by Mosby, Inc. Proteolytic Cascades Caspase-mediated apoptosis Blood coagulation cascade Matrix metalloproteinase cascade Complement cascade 23 Mosby items and derived items © 2006 by Mosby, Inc. Membrane Fluidity 24 Mosby items and derived items © 2006 by Mosby, Inc. Cell-to-Cell Adhesions Extracellular matrix Production Fibroblasts Collagen Elastin Fibronectin 25 Mosby items and derived items © 2006 by Mosby, Inc. Cell-to-Cell Adhesions Extracellular matrix 26 Mosby items and derived items © 2006 by Mosby, Inc. Cell-to-Cell Adhesions Cell junctions Desmosomes Tight junctions Gap junctions Gating 27 Mosby items and derived items © 2006 by Mosby, Inc. Cell-to-Cell Adhesions Junctional complex 28 Mosby items and derived items © 2006 by Mosby, Inc. Cellular Communication Direct linkup Gap junctions Hormonal Neurohormonal Paracrine Autocrine Neurotransmitters 29 Mosby items and derived items © 2006 by Mosby, Inc. Cellular Communication 30 Mosby items and derived items © 2006 by Mosby, Inc. Signal Transduction Extracellular messengers Convey instructions to the cell’s interior Transfer, amplify, distribute, and modulate Channel regulation Second messengers Two pathways Adenosine monophosphate (cAMP) Ca++ 31 Mosby items and derived items © 2006 by Mosby, Inc. Signal Transduction 32 Mosby items and derived items © 2006 by Mosby, Inc. Cellular Metabolism Metabolism Chemical tasks of maintaining essential cellular functions Anabolism Energy using Catabolism Energy releasing 33 Mosby items and derived items © 2006 by Mosby, Inc. Adenosine Triphosphate Created from the chemical energy contained within organic molecules Used in synthesis of organic molecules, muscle contraction, and active transport Universal fuel for all cell functions The Electron Transport Chain (cytochromes) are involved with the production of ATP 34 Mosby items and derived items © 2006 by Mosby, Inc. Cellular Energy Digestion Glycolysis - first step in the breakdown of glucose (6 Carbons) Citric acid cycle Occurs in the cytoplasm results in Pyruvate (2x 3Carbons) Anaerobic – no need for oxygen like mitochondria reactions. If no O2 present pyruvate converted to Lactate Also called Krebs cycle or the tricarboxylic acid cycle (TCA) in the mitochondria Oxidative phosphorylation Occurs in the mitochondria 35 Mosby items and derived items © 2006 by Mosby, Inc. Cellular Energy 36 Mosby items and derived items © 2006 by Mosby, Inc. Membrane Transport Gradient Passive transport Diffusion – follows concentration gradients Passive mediated transport – no energy needed Filtration – just like making coffee Osmosis – movement of water across membranes Osmolarity vs. osmolality Tonicity – describes hoe living cells react to solutions Isotonic (same size), hypertonic (shrinks cell), and hypotonic (cells will swell when exposed to this kind of solution) 37 Mosby items and derived items © 2006 by Mosby, Inc. Membrane Transport 38 Mosby items and derived items © 2006 by Mosby, Inc. Membrane Transport 39 Mosby items and derived items © 2006 by Mosby, Inc. Membrane Transport Active transport Active transport pumps require ATP move charged ions and substances across membranes Transport by vesicle formation Endocytosis Pinocytosis Phagocytosis Potocytosis 40 Mosby items and derived items © 2006 by Mosby, Inc. Active Transport Ions and charged molecules As well as large chemicals Like proteins need to be Transported across the Membrane barrier. 41 Mosby items and derived items © 2006 by Mosby, Inc. Membrane Transport 42 Mosby items and derived items © 2006 by Mosby, Inc. Electrical Impulses Resting membrane potential – caused by the distribution of charged ions like Na & K Action potential – the flow of ions when the membrane is disturbed Depolarization Threshold potential Repolarization Refractory period Absolute and relative 43 Mosby items and derived items © 2006 by Mosby, Inc. Propagation of an Action Potential 44 Mosby items and derived items © 2006 by Mosby, Inc. The Cell Cycle Mitosis vs. cytokinesis Chromatin vs. chromosomes Interphase G1 phase S phase G2 phase 45 Mosby items and derived items © 2006 by Mosby, Inc. The Cell Cycle 46 Mosby items and derived items © 2006 by Mosby, Inc. The Cell Cycle Prophase Metaphase Anaphase Telophase 47 Mosby items and derived items © 2006 by Mosby, Inc. Influences on the Cell Cycle Cellular division rates Growth factors 48 Mosby items and derived items © 2006 by Mosby, Inc. Tissue Formation Founder cells Chemotaxis Contact guidance Cellular reproduction 49 Mosby items and derived items © 2006 by Mosby, Inc. Tissue Formation 50 Mosby items and derived items © 2006 by Mosby, Inc. Types of Tissue Epithelial tissue Simple vs. stratified Squamous Cuboidal Columnar Pseudostratified Structures Cilia and microvilli 51 Mosby items and derived items © 2006 by Mosby, Inc. Types of Tissue Connective tissue Ground substance Fibers Loose and dense connective tissue Elastic and reticular connective Cartilage, bone, vascular, and adipose 52 Mosby items and derived items © 2006 by Mosby, Inc. Types of Tissue Muscle tissue Smooth Striated (skeletal) Cardiac 53 Mosby items and derived items © 2006 by Mosby, Inc.
