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This 4 page Study Guide was uploaded by Stacy Downing on Saturday January 30, 2016. The Study Guide belongs to BIOL 190 at Towson University taught by preeti shah in Spring 2016. Since its upload, it has received 27 views. For similar materials see Introductory Biology for health professions in Biology at Towson University.
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Date Created: 01/30/16
Unit 3 Review- Cells Cell Basic unit of life 2 major cell types o Prokaryotes no nucleus, 1-10 um, circular DNA, no limiting membrane, few inclusions, smaller ribosome o Eukaryotes membrane enclosed nucleus, 10-100+ um, linear DNA, nucleus, many inclusions mostly enclosed with 1-2 membranes, larger ribosome 4 Basic Structural Feature common in ALL cells Plasma Membrane Cytoplasm Genetic center: DNA Ribosome Cellular Differentiation Normal process by which immature undifferentiated cells develops distinct structures and functions of specialized cells Begins with undifferentiated cell (stem cell) Undifferentiated o Non-descript morphology o Large nucleus, small cytoplasm o Absences of specialize protein Differentiated o Descript morphology o Small nucleus, large cytoplasm, o Has specific protein and function 2 Main categories of Stem Cells Embryonic o Source: surplus embryos during from in vitro fertilization o From inner cell mass of blastocyst stage embryo (5 days after fertilization) o Pluripotent Somatic o From fetus- adult tissue e.g. umbilical cord, bone marrow o Multipotent to unipotent Difference in Potency Level Zygote: Totipotent, All types of cells including placenta Inner Cell Mass: Pluripotent, nearly all cell types not placenta HSCs and MSCs: multipotent, many cell types, example: bone, cartilage Proerythroblast: unipotent, one cell type, example: RBCs Three features that define Stem Cells Unspecialized, undifferentiated Able to specialize/ differentiate into levels of potency Able to self-renew Induced Pluripotent Stem Cell (iPSC) Adult differentiated cell Treated with 4 genes to genetically reprogram the cells Result: cell acts like pluripotent stem cells Extracellular Matrix Mostly protein material at outer surface of cells (plasma membrane) and between cells o Allow cells to attach to other cells and to ECM o Includes receptors for hormones, growth factors o Provide cell recognition ECM between cells provide o Scaffolding for tissue architecture ECM acts as a signal for stem cells to differentiate Plasma Membrane P-L Bilayer Barrier between water (cytoplasm) and water (environment), allows few molecules to cross o Prevents loss of material from cells and entry of material into the cells Function: limiting boundary, transport, identification and recognition, communication Molecule present: Proteins, CHO, Cholesterol Cholesterol: membrane flexibility Glycocalyx: identity tag (recognition) CHO chain, outside of cell Proteins: receptors, enzyme, attach ECM, transport Membrane Transport Diffusion: movement of atoms/ions/molecules down their concentration gradient, from high to low concentration, no external energy input Concentration gradient: different in concentration across space, no gradient=equilibrium Types of barriers o Fully permeable o Semi/ selective permeable o Impermeable Tonicity o Isotonic: equal water leaving and entering the cell o Hypertonic: water leaving the cell causing shriveling o Hypotonic: water entering the cell cause burst Osmosis: movement of water molecule from high to low concentration thru a membrane What can get through a phospholipid bilayer? o Very small particles, no charge o Small particles, no charge o Large structure, no charge o CANNOT: charged, polymer o Limits ability: Size and polarity/ charge Membrane Up/Down Cell Transport Examples Size and transport gradient energy protein reqrd. Charge needed Simple DOWN NO NO O2, CO2, Small, neutral, diffusion Ethanol, hydrophobic H2O Facilitated DOWN NO YES Ions, AA’s, Channel protein- Specific Diffusion Monosaccri de for each ion Active UP YES YES Carrier Small molecule Transport (AGAINS Protein T) 2 routes of membrane transport o Endocytosis: into cell, energy required, e.g. Amoeba engulf food particle o Exocytosis: out of cell, energy required, e.g. Pancreatic cell releasing digestive enzyme Cellular material to be transported and packaged in a vesicle ID tag on cells CHO chains on the outside of the plasma membrane are responsible for cell recognition EX: ABO blood groups o If a person with type A blood receives a blood transfusion of B type blood, the patient’s immune system will recognize the transfused cells as “foreign” and will destroy them. Cell to cell communication Local Long distance o Via signal molecules which binds to specific receptor proteins Signal transduction Series of molecular changes that convert a signal received on the outsides of the cell’s membrane Domino effect: one molecule alters another which alters another Junction Tight: looks like adjacent membranes are sewn together, form watery type seal, prevents passage of material between the cells Anchoring: connecting intermediate filaments of cytoskeleton to adjacent cells, provide mechanical strength to the tissues by connecting many cells firmly together Gap: form pores that provide direct connection between the cytoplasm of adjacent cells, allow flow of molecules from one cell to the next, permits communication Membrane One: ER (SER and RER), Golgi, lysosome Two: nucleus, mitochondria No: ribosomes, fibers of cytoskeleton Advantages of compartmentalization Increased surface area Increase concentration of reactants used in chemical reactions Separation of incompatible reactions/ reaction environments Separation of products based on whether they are for internal use or export Organelles Nucleus: double membrane (nuclear envelope), continuous with ER, stores DNA Nucleolus: site of rRNA coding genes, ribosomal subunit assembly Chromatin: stretched out form of chromosome, active gene expression Nuclear Pore: protein and RNA traffic Ribosome: o Free: floating ribosomes in cytoplasm, making proteins in cytoplasm, translation of proteins used in cytoplasm o Bound: ribosomes attached to RER, involved with translation of membrane proteins Smooth Endoplasmic Reticulum (SER): single membrane, lipid synthesis, detoxification, Ca ++ ion storage Rough Endoplasmic Reticulum (RER): single membrane, membrane-associated proteins, proteins for delivery Golgi: single membrane, finishes, sorts, package, ships cell products Lysosomes: single membrane , contains HYDROLASES: acid enzyme that works in acidic conditions, cell’s recycling center Mitochondria: double membrane, cellular respiration (ATP synthesis) Cytoskeleton: 3D network of protein fibers in the cytoplasm Types of protein fibers: o Microfilaments: thinnest fibers, function cell shape, whole cell movement o Intermediate Filaments: function cell shape, reinforcement of cell junction, organelle placement o Microtubule: thickest fibers, function arrangement of organelles, cell motility Properties Plasma Membrane Cell Wall Chemical Mostly lipids(and some proteins and Mostly cellulose Composition carbs) Thickness Thin Thick Flexibility Flexible Stiff, rigid Permeability Selectively permeable Porous v. permeable Location Outer layer of cell External to P.M Function Gatekeeper Structural support Cell Type ALL! Plant cells, some fungi
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