Popular in Bil
Popular in Biology
This 41 page Study Guide was uploaded by Mikayla Farr on Thursday October 30, 2014. The Study Guide belongs to 150 at University of Miami taught by Mallery in Fall2014. Since its upload, it has received 137 views. For similar materials see Bil in Biology at University of Miami.
Reviews for BIL150NotesTest2.pdf
Report this Material
What is Karma?
Karma is the currency of StudySoup.
You can buy or earn more Karma at anytime and redeem it for class notes, study guides, flashcards, and more!
Date Created: 10/30/14
Lecture 10 Cellular Organization Cell Types Procaryotes amp Eu karyotes 93014 Cell Organization 3 basic parts of a cell 1 Membrane selectively permeable inout 2 DNA Region nucleoid or nucleus 3 Cytoplasm aqueous compartment and any of its subcell parts organelles 2 successful Cellular Plans of Organization prokaryotes examples archae blue green algae and bacteria are primitive simple versatile and have a unicellular life form make up 80 o 90 o of total biomass on planet earth genes are naked DNA with no protein complexes and no real chromosome lack complex membrane bound organelles eubacteria 3 common bacterial shapes cocci spherical bacillus rod shapedpill shaped spirochetes spiral categorized by gram staining a method for the differential staining of bacteria smears are fixed amp stained in a solution of crystal violet and then treated with iodine solution rinsed and then counter stained with safranin O Gram staining is useful in bacterial taxonomy and identification and also in indicating fundamental differences in cell wall structure Gram positive bacteria stain purple black walls contain peptidoglycans protein carbohydrates Gram negative bacteria stain pink thinner walls more membrane like lipopolysaccharides Often possess flagella for motility Can be pathogenic and cause diseases A lhurlriai while lalmm mill ugngulrs ir itifii ii llli393iri2quoti quotlta riit Sfaphyfacactus iiurErir5 i39iirI gmtItiI C i i Bar the Ssti39 ntf5t stair December 9 2213 l laczsillll us 5 pliirmlhetg5 l haped ttnacliiiiif ip iralI Sjpifteariical lEEtEEiI r o Cyanobacteria often called blue green algae but no relationshipare aquatic photosynthetic unicellular eubacteria have cytoplasmic membranes may catalyze N2 fixation N2 gt NH3NO2 NO3 for amino acids Eukaryotic Include the fungi algae protozoa slime molds and all plans and animals Contain many internal membrane bounded organelles Has 7 common characteristics Has a nucleus Genes in chromosomes Contains 1000x more DNA than prokaryotes Presence of flexible cell walls Extensive internal membranes Presence of cytoskeleton Presence of organelles Reproduce sexually Usually larger in cell volume 2 main types of eukaryotic cells animal metazoan cell heterotrophic feeder plant metaphytian cell autotrophic feeder contains chloroplasts large vacuoles cellulosic cell wall 2i l i1 F39earson Education Inc Table 2322 A Cemparison of the Three Drnains of Life CHAlRACTlERllSTlC DOMlAllN Bacteria Airchaea iiukarya ilurl ear envelope Absent Absent Presertt ii fiEfH1i3F lF1E eEiquotiCiDSEquotCi Absent Absent Presertt organlelles lP39eptidogiyclain in lP reser1t Absent Absent Ce lgiggwal I islelmbrane lipids Unlbranchled Some Unbranehtedl hydrecarblonsl brancited hlydliroiclarbions hydrecarbens RNA polymerase Onew lkind Several kinds Sletreral kiincls llinitiator amino acid lFermfy livlethieniine Mlethionline tor pretelin sylntlhesis niiE39thli39DininE llntrotns in genes Very rare Preseint in i3liESEillquotlii in some genes many genes Response to tlhe Grewtlh Glrowtlh not C rowtlh not antilbicutics inlhibited inlhibited inlhibitecl streiptomyeiin and icblloiramphvenieol lrllistone5 assocziated Absent li treseint in ii39lT ElSEili39lii with lDlNA seime species Circular iPi ESE39l l 1i lilreseint Absent chirerniosome Growth at temp ifiiD Some species No eratures 100 C Organeles a subcell part that has a distinct metabolic function Identification of Subcell Parts Light microscopy an ordinary microscope that uses light as distinguished from an electron microscope which uses a beam of electrons Microscopes have 2 key functions magnification how much larger objects appear For a light microscope it is typically 1000 fold Resolution distance between objects allows one to distinguish two dots 2 dots 200nm 02um Types of light microscopy Brightfield microscopy Standard transmission of light through a living cell has very little contrast A cell is 70 water thus most of the cell is basically colorless and translucent ie invisible to the eye Phase Contrast Microscopy Incident light iL is out of phase with transmitted light tL and when the phases of the light are synchronized by an interference lens a new image with good contrast is seen Nomarski phasecontrast is also known as differential interference contrast microscopy The different phases of incident and transmitted light are synced by a set of special condenser lens mounted below the stage of a microscope Dark Field Microscopy Here the illuminating rays of light are directed from the side so that only scattered light enters the microscope lenses consequently the cell appears as an illuminated object against the view trout amp melanocytes Fluorescence microscope a light microscope that views emitted fluorescent light from a fluorophore as GFP bound to a cellular molecule used for localizing specific proteins within cells fluorescent molecules absorb light of one wave length and emit fluoresce at longer wavelength Confocal microscopy a form of fluorescent microscopy but instead of flooding an entire cell sample with light to excite the fluorophore which results a blurred image a pinpoint laser light source is used to excite the fluorophore resulting in enhanced contrast Electron Microscopy a type of microscope that uses a beam of electrons to create an image of the specimen It is capable of much higher magnifications and has a greater resolving power than a light microscope allowing it to see much smaller objects in finer detail resolution of O2nm 20nm 3 types of electron microscopy TEM transmission stained w OsO4 metal that binds to lipids membranes SEM scanning 2nd electrons emitted by metal shadow cast from electron beam FEM freeze fracture Image summary Brightfield l Brightfield R E Phasecontrast Difter entiaI unstained 50 quot1 stained specimen interference contrast specimen Nomarski is 50 pm Fluorescence IE Confocal without Confocal with E 10 pm 3 Ti Deconvolution l l 3 l i WW I If i Super resolution Super resolution F Scanning Transmission i i without with electron 2939 electron 2 pm microscopy SEMI microscopy 39i39El lll 2014 Pearson Education Inc Electron Microscopy has given us major eukaryotic cells such as NUCLEUS envelope pore chromatin nucleolus nucleoplasm MITOCHONDRIA perimitochondrial space cristae mitoplasm matrix CHLOROPLAST peri choropast space thylakoids chloroplasm stroma RIBOSOME small subunit large subunit polysome ENDOPLASMIC RETICULUM smooth amp rough GOLGI BODY sided cis amp trans endomembrane pathway LYSOSOME hydrolytic enzymes MICROBODIES peroxisome amp glyoxysome CYTOSKELETON microfilaments microtubules intermediate filaments CENTROSOME centriole basal body flagella cilia INTERCELLULAR JUNCTIONS tight junctions desmosomes gap junctions plasmodesma PLANT CELL VACUOLE tonoplast cellular waste and osmoregulation CELL MEMBRANE selective transport barrier Lecture 11 Major Cell Organelles 10O62014 Animal Cell allitnizhiandlrin Flagellum l39393quot amprunial5rme Eanlinlimiles I C ll P t 0 Heifer 39 A m 39 p I h v C enwu E l A A A l C l P V V l3939 gtHLlIEILELl5 T T g V 1 X EI39llI Ia391Illl39lll39ll 139In rclllcxrru lanmente Q S N 0u J 5 1 7 Nlu lg lusg l Huugh iEll1l2IEliFlIIEfEllllll39 il a lr ti ill ll W FI 39llmesngnhuge L gI39iEiquotl391E l C Fiaenm mawlihiralnu a lgi K pmmtmg C Eamnnt erndnplasrimlin el 139lIllI9l I 1quoti39lnli39au39ulni39Ji 8 ha r ii luluml Plant Cell Lecture 11 Major Cell Organelles 10O62014 Taf39IIlZi I i5l HQhh 39l tirannIlule 39 Q lrllusclear I entwralnpa A P H 1 1 p IquotiltI3llEillE EI39Ifl3939l39I lI l39ll lr 0B 0 1 1 E quot iquotli lr ntuIules R tlttilampIltlts Ftouah 8 39Eiquot39lslquotiI3 Il ElTlquotiIZ W I EIllllllIlIIquotI1 39E 39 quot39 Fquot55 t Emiuntgh nensdnpllusmic r u Mm 2 Filsaslm nadasntta M 1 lPEarIuiiiE rIirtl1eE H Flrlt iliitittti s E5 hi 39 39ellwtttllJ 1 1 F 1 G1ulgi apparatus Plasma rrlrantllsrrainan rI 2Iti9H weaefa3 1 Ira Nucleus First described and named by Robert Brown in 1831 stamens of Tradescantia virginiana First localization of DNA in cells was by Frederich Meischer in 1869 from white blood cells and the sperm of trout The nucleus is the largest organelle Maximum diameter of 10um volume of up to 40 um3 10 of cell volume Found in all eukaryote cells Has evolutionary origin the membrane surrounded an early prokaryotes nucleiod Mesosomes folded invaginations in the plasma membrane of bacteria that are produced by the chemical fixation techniques used to prepare samples for electron microscopy Components of the nucleus Nuclear envelope nucleus is a double membrane bound organelle Nuclear pore complexes amp structure nuclearpore complex functional diameter of pores 10nm Responsible for nuclear transport Lecture 11 Major Cell Organelles 10062014 There were several nuclear transport experiments to determine pore sizes and transport mechanisms 1960s Carl Feldherr injected gold particles in unicellar amoeba s 1970s used fluorescent tagged proteins showed proteins less than 60000MW passed 1980s Ron Laskey studied a nuclear protein nucleoplasmin and used autoradiography to follow it s movement found that it holds a 17 amino acid sequence that targets transport into the nucleus known as the nuclear localization signal Chromatin the genetic stuff inside of the nucleus DNA complexed with histone proteins and acidic nuclear proteins Heterochromatin dense and inactive Euchromatin less dense and active Nucleolus site of rDNA genes which make rRNA Nucleoplasm soluble aqueous phase of the nucleus that contains enzymes RNA s solutes chromatin etc Role of the Nucleus It is the site of genetic information and controls cell divisions amp heredity Mitochondria Was first described in the 1900s with vital stains as Janus Green B Today it is best seen via TEM with fluorescent dies and false color scanning EMs Site of cellular respiration redox reactions oxidation of CH2O gt CO2 H20 Gas exchange in cell CO2is released and O2 is taken up and reduced KREBS cycle metabolic pathway oxidizes pyruvate Respiratory ETC chain and oxidative phosphorylation which makes up ATP Mitochondria plays a role in It is site of conversion of covalent bond energy of food molecules into ATP It couples redox transfers of electrons and hydrogen proteins to ATP synthase Structure of mitochondria Elongated cylinders to oblate steroids 35um long by 0510 um diameter 20 to 1000 per cell The more active a cell the greater their numbers Can make up to 2000 of a cell s volume Has it s own circular DNA 16569 nucelotide pairs and about 37 genes Has it s own ribosomes prokaryotic size and protein synthesizing ability Holds enzymes for cellular respiration Double membrane bound organelle Outer membrane contains transport protein porin which passes molecules up to 5K Inner membrane very selectively permeable and impermeant to most molecules Lecture 11 Major Cell Organelles 10O62014 Perimitochondrial space in between area where Htaccumulates Hydrogen Ion Pump H a membrane bound protein that transports hydrogen ions against a concentration gradient and creates a positive charge on one side of a membrane Cristae inner membranes that hold the respiratory assemblies of ETC Mitoplasm matrix aqueous compartment holds DNA ribosomes KC enzymes etc Plastids Group of a double membrane bound plant cell organelles found in all higher plants Produces all of the organics required by metazoan cells sucrose etc and stores polymers of carbon amp contains various pigments Proplastids A precursor plastid to all the other plant plastids Found in apical meristems dividing cells similar to stem cells of rootshoot tips Local cell environment defines the types of plastids to be made from proplastids Types of Plastids EtiooIasts plastid whose development into a chloroplast has been arrested stopped by lack of light They contain a dark crystalline bodies called prolamellar body which is essentially a cluster of thylakoid membranes in a somewhat tubular form Leucooasts non pigmentous 2x5um variable shaped plastids for storage Amyoplasts colorless plant organelle related to starch production amp storage Aleuroplasts colorless plant organelle related to protein production amp storage Elaioplasts colorless plant organelle related to oil amp lipid production amp storage Chromoplasts often red yellow or orange in color they are found in petals of flowers and in fruit Their color is due to two pigments carotene and xanthophyll Primary function in the cells of flowers is to attract agents of pollination and in fruit to attract agents of dispersal Chloroplasts Develops in the light from proplastids Site of autotrophic metabolism Has an oblate spheroid shape 23 um diameter by 510 um long with 15 100s of cells has an aqueous stroma chrloroplasm that holds internal memberane system made of thylakoid membranes scaning EM of chloroplast GRANA stacks and lntergranal membranes 70s ribosomes bacterial size Eukarya have different sizes ribosomes 80s lipid droplets Lecture 11 Major Cell Organelles 10O62014 naked DNA pieces highly supercoiled and repetitive starch granules amp pyrenoids enzymes of CO2 reduction to CH2O Endosymbionts any organism that lives within the body or cells of another organism quotMitochondria amp Chloroplasts are derived from prokaryotes which were once free living but joined into a symbiotic relationship with eukaryotic aerobes during cellular evolutionquot Lynn Margulis Pelomyxa palustris is a eukaryotic amoeba that lacks mitochondria yet holds aerobic bacteria within its cytoplasm in a symbiotic relationship Similarities of Bacteria amp MitochondriaChloroplasts Both organelles are double membrane bound Both are semiautonomous Derived from themselves by divisional fission Replicate independently from their cell hosts Both have their own DNA a circular molecule like DNA of prokaryotes amp protein biosynthetic systems can make some of own proteins DNA sequence homology each has similar DNA sequences Mitochondria DNA related to aerobic bacterial DNA Chloroplast DNA related to cyanobacterial DNA Ribosomes are same size as bacterial ribosomes 70s in eukaryotes80s Ribosome A non membrane bound organelle A subcell ribonucleoprotein particle RNP A complex of RNA amp Proteins discovered by George Palade using TEM Site of cellular protein synthesis Spheroid shape 17 to 23nm diameter Composed of two subunits Small subunit and large subunit which binds tRNA s functional structional Prokaryotic vs eukaryotic compositin 35 protein and 65 RNA Email Euhun Found in 3 different places in cells Lecture 11 Major Cell Organelles 10062014 1 Free in cytoplasm as individual subunits or dimers 2 Membrane bound an outer surface of endoplasmic reticulum membranes 3 Attached to mRNA molecule in a polysome polyribosome Endoplasmic Reticulum set of internal membranes Found in all eukaryotic cells with a nucleus Has structural continuity with the nucleus ie it s contiguous E39tID F39LASMIE u39 tllhrrmratlm y w FET39lmCuLumEl 1 n p Hiuiteialus tlia lLlI Il392 LELl5 rt Nucleazr enuelapa rHnIugEl1E H armiesin an 391 p V lFIa39gElllI39l II lquotla H s 5 35 t lliCE lquotE l3939tl iI lFJE amen lquot39ilIlII39ir H imembiane inrur I1IJtrIlEazr39 EFI rl1emlmrane IEJFI E eni39trr asame3 g 1 lumen l ar afflfsarrttse quot 1 f jg i j jb quott tllhznanmes 1 Gulgqil aptpa rrrtutsa F fi iEEIEHT nuclear I fie p quotquot3939quott lMiilcrmriillIi 1 I T 3n 0 l Til i iiirliEnd k l1II ll asma membrane MlcrnfilammnI5quot 05g k Mnmmndrmn T Il niterrmadliarteflllaments P h e zlin 4ElI39IllTFi m EI x 5j j i 2 139uir39 eats llillcrqtluilbulles I IL grausntme Ea mmi Wang and m p vplast E1IrT 5 KE LET N Elilll 1llil lFIlmillfi d il i t makes up 50 of all internal membranes of a cell composed of flattened sheetsacs and tubes of membranes convoluted 32 membrane network enclosing internal spaces lumen is internal compartment of cisternae makes up 10 ofall ce s volume 2 types of ER Smooth ER SER tubular membranes without ribosomes Lipid and bile biosynthesis and drug detoxification oxidizes drug molecules Rough ER RER surface of cisternae with ribosomes Synthesizes transports and packages proteins into membrane vesicles Lecture 11 Major Cell Organelles 10O62014 ltlruclloaar lletsmm1 i Hill i i 1 quot 1 1 P Q ii Addlscct W e ay IQ Inn Q Q Signal sequence a short 530 amino acids long peptide present at the Nterminus of the majority of newly synthesized proteins that are destined towards the secretory pathway Bind to receptor protein and release into lumen Gycosylation adding carbohydrate groups to ER proteins glyooproteins which will help transport the proteins to specific cell sites proteins have many sorting signals Golgi Bodies A part of the endocytotic pathway The cell s internal membrane system for endocytosis packaging of extracellulr molecules for internal digestion exocytosis secretion packaging and delivery of newly synthesized proteinscarbohydrates for extracellular secretion have up to 100 per cell are about 1 to 3um in diamer and 4 to 7 membrane stacks high CIS side entry side faces RER proteins made on RER They then pass from ER lumen gt vesicles gt cis Golgi Lecture 11 Major Cell Organelles 10O62014 MEDIAL cisternae elements proteins are modified with sulfates carbohydrates amp lipids modifications gt quotaddressquot vesicles to a destination TRANS side exit Golgi side modified vesicles leave as export vesicles lysosomes other membrane bound vesicles E llgiic T apparaatus CIS face reteiuit1glquot side at Gleslgit app gs raturslr pA UqilcImmaHa 39tfaiIcilass 0 to T mi Mn r EH19 Ealgal 1quot uncut cits Bwolgalr i1iitiItruin G r ttfnictu also amln T psrwllallriwi in EIFIT clisttsranlaa E l f mImmlnn t etmmn ltnlr ttatlj rlurtlr In 9 Waterloo and quot tlaartna Galgjla j spaei r ltlmrftelinnz quotIto T 0 or to nam m cliniclit ipni ic TRAN5 ffilt 9 T TT plrmteiins u In I quot5I1Ipplng side ruff 2 T T T I Gail all Enlglli apparatuall TEM all Eolgli sapparaturs Lysosomes amp Proteasomes Organelles of Cellular Digestion Lysosomes a cytoplasmic single membrane bound vesicle containing hydrolytic enzymes with acid pH optima pH 50 lysosomal membrane has ATP driven membrane hydrogen ion pump faces in 1 Hamlin 19 lyssmull aE39 FiTTiquotEl39EquotlsE393 ENE MEquot P U EiiEVTtFi a TE rIt lrErii plltnshuf e inemwes tphnshafe rmzriizll t i aizlrigesf nucleic acids tZ iglE3939E I39 Trains Tgltuireie5i dquotiI5 e dl39 lE3939E I39 lljrtar1irliili39i d e haa phlinse pl1n5ha i pid5 5 tt1 IiEItltI1r tIt39tuE have diverse shapes mostly spherical functions in intracellular digestion phagasomes and autophagy Lecture 11 Major Cell Organelles 10O62014 Proteasomes Large barrel shaped protein complex found in all eukaryotes and archaea and in some bacteria that are responsible for intracellular protein digestion Ubiquitin binds to proteins and transports them into a proteasome Endocytotic Pathways Migration path through the various organelles of the endomembrane system first proposed by George Palade The endomembrane system is a complex part of the cell s compartmental organization Nuclear envelope is connected to the rough ER and smooth ER Vesicles made by the ER flow as transport vesicle to the Golgi for modifications and from the Golgi to intracellular location or extracellular release Exocytosis golgi modifies the molecular composition and metabolic function of the endomembranes as they flow from the ER through the Golgi Golgi in turn pinches off vesicles that give rise to lysosomes and vacuoles Plasma membrane can fuse with vesicles born in the ER and Golgi resulting in the release of proteins to the secretory protein pathway and other products to the outside of the cell in exocytosis Endocytosis external material is pinched off into a vesicular endosome which can fuse with a lysosome for intracellular digestion Vesicular transport a major transport system in cells 2013 Nobel Peace Prize Winners Rothman Schekman and Sudhoff identified 3 classes of genes that regulate proteins binding vesicles to targets including signal hormones and neurotransmitters Protein sorting proteins bound for different destinations have different carbohydrate tags Know of 3 different ways to tag proteins for transport Nuclear localizing signal Signal sequence Carbohydrate tags Cytoskeleton Network of protein fibers running throughout the cytoplasm of all cells prokaryotes and eukaryotes that give a cell its shape and provide a basis for movement cytoplasmic streaming Proteins that make up the cytoskeletal network include 1 Microfilaments actin 7 to 8nm diameter and of indefinite lengths o Actin is a universal contractile eukaryotic protein Lecture 11 Major Cell Organelles 10062014 0 Makes up 5 of total cell protein 0 Linear filaments F actin of polymerized monomeric globular proteins of G actin a conserved polypeptide of 375aa with ATP molecule recognition site 0 3 types of G Actins alpha actins of muscle cells actin myosin beta and gamma actins make up cytoskeleton and are involved in cell motility o microfilaments make up microvilli of epithelia o microvilli of epithelia cellular membrane protrusions that increase the surface area of cells 2 Intermediate filaments 10nm diameter ie keratin vimetin and lamin protein fibers that are rope like with an intermediate diameter Spans cytoplasm providing framework for mechanical strength made from a hetergenous family of filamentous proteins 3 Microtubules Tubulin proteins also highly conserved evolutionarily 21 25 nm diameter May be up to several um long Make long fibrillar helical protein complexes that form spontaneously Made of repeating globular units 2 different proteins alpha and beta tubulin Lecture 11 Major Cell Organelles 10O62014 Table 61 The Structure and Furlction of the Cytoskeleton Property Microtubules lTubIuIin P oIyrners Microfilaments Actin Filaments s intermediate Filaments Structure Hollow tubes 39lfwo intertwined strands of actin Fibrous proteirts coilecl into cables Diameter 25 nm with 1S nm llllT IEl39l rim Bl2 nm Protein subunits Tutbulin a dimer consistirtg of Actin if One of several different proteins o tubuin and Ertuhulin such as keratins ltelain quotfunctions Maintenance of cell shape Maintenance of cell shape ter1sion Maintenance of cell shape tension compre5siortresisting quotglirders bearing elements changes in bearing elements anchorage of cell motility as in cilia or flagella cell sltape muscle contraction nltucleus anld certain other organu chromosome motremerlts in cell cytoplasmic streaming in plant elles lorn1a tion of nuclear larrlirla Cll tfl SlOl39l organelle l39ll39lCquot tl39Elquot lquotlEl lIl5 cells cell mo tili ty as in amoeltaoid movement division of animal cells lluoresceme micro graphs of fibroblasts l ilroblasts are a favorite cell type for cell biology studies ln eaclt the strtlcture of interest has been tagged with fluorescent molecules 39l39l1e DNA in the rlucleus has also been tagged in the first micrograph blue and third micrograph orange 1 Column of tubulln dimers V i llteratin proteins g Acllll 5UbU ll Fibrous subunit lkeratins 39 39 39 39 quot g e coiled together if k cu t H Tubullin dimer 2014 Pearson Education Inc Other Cytoskeletal Elements and or Organelles Centrosome Microtubule Organizing Center found in most eukaryotic animal cells from which MTs emerge site of MT nucleation organizes cilia and flagella and the mitotic spindle facilitates spindle fibers formation Flagella microtubule extensions projecting from cells usually used for propulsions via an unduating like motion ex sperms and algae Cilia microtubule extensions held in place in tissues that move fluids over the tissues acting like cars via alternating powerrecovery stroke cycles Plays 2 roles 1 motion as in clearing trachea of foreign substances 2 some diseases missing dyein arms leads to infertility in human sperms Both have same structure 9 microtubule doublets surrounded by 2 singlets in center collectively allied an axoneme Basal body a centriole found at the base of flagella or cilia quot1 a 1 quotw a 39 n N u 1 139 Rxquot K 2 Lecture 11 Major Cell Organelles 10O62014 Dynein dyne for force and in for protein hydrolyzes ATP Discovered by Ian Gibbons in 1965 Cytoskeletal Protein Elements amp Cell Motility Actin filaments bear the tension wires forces of the cytoskeleton Microtubules are the compression rods units providing internal structural support for cell organelles Contractile force of muscles myosin amp actin microfilament are motor proteins that via repeated cycles of binding amp release contraction Amoeba s crawl along a surface via pseudopodia due to the assemblydisassembly of individual actin subunits on microfilaments shifting between solgel phases Cytoplasmic streaming in plant cells occurs via actinmyosin interactions and solgel transformations which results in a circular flow of cytoplasm around the cell Cells respond to pressure by building and branching actin filaments Motor proteins movements of organelles via the cytoskeleton ie kinesin a dimeric motor protein powered by ATP lntercellular junctions Cell surface regions specialized for intercellular contact multicellularity especially prominent in epitheial cells of animals Has 3 major functions 1 impermeabilize areas 2 adhering junctions 3 communication Tight junctions they impermeabilize regions prevent leakage of materials between epithelial cells Desmosome an adhering junction anchors cells together Spot desmosome spot weld with keratin amp cadherin proteins Belt desmosome zona adherens wide band of desmosomes Gap junctions intercellular channels for communication Allows ions electric impulses etc to pass between Plants have no intercellular junctions as above due to polysaccharide cell walls Plasmodesma cytoplasmic strands between plant cell walls MT can pass through The plant vacuole A membrane bound torroplast vacuolar membrane sac that plays roles in intracellular digestion and the release of cellular waste products In animal cells vacuoles are generally small In plant cells vacuoles tend to be large and play a role in maintaining turgor pressure Lecture 11 Major Cell Organelles 10062014 When a plant is well watered rigidity When water is insufficient wilts Vacuoles accumulate toxic wastes Vacuolar membrane holds transport proteins mostly active transport carriers for one way accumulation of toxics into the vacuolar spaces Endodermis and Casparian Strip in plant roots Endodermis an innermost layer of cells in the cortex of plant roots Forms a cylinder of tissue that separates the outer root cortex from the inner vascular stele Contains a waterproof Casparian Strip made a wax like insoluble molecules that runs completely around cell making the cells impermeable to exterior flow thus all materials must move into and through the endodermis cells to reach the transport cells of the inner cortex of the root Symplastic route internal via plasmodesma Adoplastic route external via intercellular space Lecture 12 Membranes and Cell Communication 10062014 The Cell Membrane how things get inout of cells Two ways to study membranes and transport of solutes across membranes a nature of membrane itself molecular makeup and permeability studies physiological properties of membranes Fluid Mosaic Model two major molecular components Lipids amp proteins Proteins integral intrincsic denatured upon release from peripheral extrinsic which easily extractable from membrane Physiological Properties of Membranes Solute movement movement of molecules across a membrane is based upon lipid solubility more lipid soluble greater transport Movement of Water is polar not lipid soluble yet readily permeable weird Bulk flow hydrodynamics or mass flow of water due to potential energy of water Water potential the chemical energypotential of water and is a measure of energy available for reactions or movement Measures the ability of water to move Water always moves from areas of high water potential pure water to an area of low water potential diluted water hwp to lwp Osmosis net movement of water from HWP to LWP Energy is usually required except in passive transport Solutions comparing one solution to another Hypertonic solution more solute less water hypersmotic Hypotonic solution less solute more water hypoosmotic lsotonic solution equal solute and water isosmotic Plasmolysis loss of cytoplasmic structure due to water loss Turgidity swollen cells due to water gain Aquaporins water channel proteins Membrane Solute Transport ion or molecule transport 4 ways for solutes molecules to get across a membrane Lecture 12 Membranes and Cell Communication 10062014 through a pore made by proteins embedded in bilayers by dissolving in membrane by carrier proteins by membranes engulfing particles into membrane vesicles endocytosis exocytosis Membrane Transport Diffusion net thermal motion of solute down a concentration andor electrical gradient is passive requires no energy Carrier mediated transport a special type of diffusion also called facilitated diffusion Defined as protein mediated passive transport facilitated by either channel proteins or carrier proteins Active transport cells expend energy to move a solute against a concentration gradient often spitting of ATP In animals a sodium pump and in plants a proton pump Both are electrogenic and move charge only one way Cotransport movement of 2 solutes together often moves 1 solutely passively down and other actively up gradient Uniport single solute in one direction Symport two solutes simultaneously in same direction Antiport 1 solute in and 1 solute out opposite directions Exocytosis releases out bulk material to outside Endocytosis takes in solutesparticles by vesicles Cell Communication Receptors protein contained in the cell membrane that binds and transmits extra cellular signal molecules converting signals into specific cellular responses Signal transduction the most common method of cell communication where an exogenous molecule is received by a cell and converted transduced into a response by the receiving cell Signaling can be local or distant Paracrine local signaling local regulator chemical messengers are targeted to specific receptors Often includes growth factor proteins that promote cell division and growth amp neurotransmitters that move across synapses to other neurons Lecture 12 Membranes and Cell Communication 10O62014 Endocrine distant signaling specialized cells release molecules often hormones into blood vessels of circulatory system hormones move to distant target cells elicit response 3 stages of cell signaling process reception only one receptor protein bound within a cell membrane transduction leads to a conformation change in receptor Inactive enzymes to active enzymes Response usually a cellular activity as enzymes catalysis or the rearrangement of cytoskeleton movement or specific gene activity Generic example G Protein Receptors receptor proteins that bind GTPGDP amp convert between active amp inactive forms R Lefkowitz amp B Kobilka 2012 Nobel Prize 0 G protein receptor structure has 7 transmembrane oc heicies amp has site for signal molecule and G protein to bind a signal molecule binds to a receptor gt conformation change thusly gt an inactive G GDP protein now binds GTP replacing GDPand active G GTP protein stimulates other inactive enzymes if G Protein has its GTP hydrolyzed gt it inactivates G proteinbind to G protein keeping it active Lecture 13 Bioenergetics and Cell Metabolism 10O62014 Fundamentals of Cell Metabolism Design of metabolism how biological order comes about how cells transform energy Metabolism the catalytic reactions run by enzymes in cells most often via metabolic pathways ABCDE Classifications of cellular catalytic reactions are Anabolism biosynthesis often via coupled reactions energetically unflavored with favored reactions Photosynthesis synthesis of ATP and NADPH amp reduction of CO2 to CH2O Catabolism chemical oxidation of food stuffs or cell respiration Digestion of polymers carbs via hydrolysis reactions often to glucose Glycol lysis glucose pyruvate Anaerobic splitting of glucose Krebs cycle aerobic oxidation of acetyl CoA Electron transfer ATP synthase uses hydrogen proton gradient to phosphorylate Energy Transformation the change from one type of energy to another type while making something happen which often releases energy as heat Energy is often defined as capacity or ability to do work and work is a measurement of change in a system over time Types of energy Kinetic energy of motion Potential stored energy capacity to do work Heat association with movement of molecules in a body of matter most random form of energy wasted Chemical bond energy molecules in living cells with chemical potential energy to do work because of the arrangement of their atoms in space Energy in cells is stored in the covalent bonds of their molecules Most of cellular energy is needed to maintain homeostasis a steady state condition that keep cells away from equilibrium Lecture 13 Bioenergetics and Cell Metabolism 10O62014 Bioenergetics the study of energy transformations changes in biological systems based upon Equilibrium thermodynamics 15 law conservation of energy energy is constant and cannot be created nor destroyed only transformed 239 law energy transformations favor reducing the order of the universe thus entropy is a measure of disorder in a system entropy is directional toward equilibrium toward maximum disorder cells become more highly ordered as they divide and grow for part of a system to become more ordered lose entropy its surroundings must become more disordered gain entropy heat most disordered form of energy max entropy Josiah Gibbs Free energy equation measures energy changes in metabolism in cells AG AH T AS free energy enthalpy entropy AG a measure of change in amount energy in a system that is able to do work a numerical measure of how far a chemical reaction is from equilibrium Entropy increases disorder increases when useful energy that which could be used to do work is dissipated as heat AH enthalpy is internal heat often measured as heat released in a reaction but cells are isothermal thus AH above is approx 0 It is essentially negligible in the equation Chemical Reactions Exergonic reaction one which releases free energy Product B ltlt energy REACTANT A energy stored in covalent bonds is lost Cell respiration cellular burning of glucose molecules Slower multistep process that captures as conserves some energy such as ATP Endergonic reaction requires input of energy for A B Product B gtgtgt energy than REACTANT A Cell Metabolism is then a mix of exergonic and endergonic reactions that occur inside of cells Coupled reactions often involve the linking of the hydrolysis of ATP a favored rx to a thermodynamically unflavored reaction thereby creating biological order greater molecular structure ATP adenosine triphosphate its structure is its source of energy Lecture 14 Bioenergetics and Cell Metabolism 10062014 How Cells make ATP by phosphorylation adding a phosphate to ADP ADP P ATP Substrate level phosphorylation where a substrate molecule donates its P to ADP making ATP Chemiosmosis food substrates donate e and protons to acceptor molecules via oxidation NADH passes on electrons and protons are pumped out of mitochondria Protons diffuse back into mito thru an enzyme ATP synthase The ATP synthase enzymes makes ADP P ATP Photophosphorylation e of light energy instead of food covalent bonds are captured by chlorophylls to make a proton gradient across the chloroplast membranes Protons move through a chloroplast ATP synthase enzyme to make ATP Oxidative Metabolism occurs in heterotrophic organisms that consume foods Organisms oxidize consume foods to make energy because it removes and captures electrons Energy is mostly in the covalent bonds So metabolism is cells capturing e via redox reactions Redox reaction e passed from one molecule to another in a chemical rx energy is transferred into the new molecule a redox couple by holding e Oxidation removal of electron ampor protons from food covalent bonds Reduction gaining electron ampor protons adds an electron to an acceptor molecule The more reduced the more energy it holds AH EG Etr A BOH il tntr39A nccsepfn rt 2 H EEp3939Etlquot iliinir 0 Mam if mun reducing i i idili g becomes hemmzas ingenf ng En 139 nrtidizEil PEdu r d an emttlmple mzcapfnrr E EH1 fH1 r39ed7itc ro ufilE i H i f h JADH Thus mE39ltnboli 5 m Izrnerznrttngs fhae 539139napwise m iilulison inf iiiI 5 if erquotL39lr rnequires mqrgen hiE eliecfran rlEEiEF39T l if anaerobic requiiraes nu bmrgen uses nfhagr nquot actEp39139nrs Lecture 14 Bioenergetics and Cell Metabolism 10O62014 Cell Respiration is Series of enzyme rx s in biochemical pathways in the cytoplasm and mitochondria Oxidation of glucose pyruvate Oxidation of pyruvate CO 2 H2O amp reduction O2 to H2O Called oxidation because e removed from glucose substrate Called reduction because e passed to O2 making water Passed e to acceptor molecules redox coenzymes Electron transport and phosphorylation of ADP via ATP synthase Terminology oxidative phosphorylation chemiosmosis GLYCOLYSIS iTPYFlUlVATE po o 1 OXIDATIVE OXllDAT ll0N g PlHOSPH0lBYLATlON Guco5e 9 pyruvate P O rElectror1 transport pT V 1 and chemiosmosis V CYTOSOL p 0 o o o 0 o t Substratelevezl Substratelevel Oxidative 2014 Pearson Education Inc Enzyme Pathways of Cell Respiration Glycolysis Pathway converts 1 glucose C6 to 2 pyruvate C3 yield 2 C3 2 NADH and 2 ATP Occurs in the cytoplasm amp is anaerobic Ferment KEY REACTIONS OF GLYCOLYSIS Substrate level phosphorylation occurs twice Redox reaction Reaction paths investment phase amp payoff phase Lecture 14 Bioenergetics and Cell Metabolism 10O62014 EUMMAFW of ErLH39C39DLquot Jquot5T5 Figure4 2 ATP to i ni39l39i 139e E substrate E39iIquotEl Jquot39lvD 3939IDlquot1uiquot39 1 DI1i sfepa E 4 ATP grass ATP net 1 re ux squotl39eg molding NADH thus E iycnlysis l39l39l kES what goes in 5 came out 2 may 2 MAoH and E P RUVlTES remember the rule of H1E Fer39men39tntinn5t 6 5hu139J39e5r KREBS Cycle Oxidizes 2 pyruvates to CO2 H20 Produces 8 NADH 2 GTP 2 FADH2 Releases 6 CO2 Occurs in the mitochondria is anaerobic requires 02 ETC Electron Transport Chain Uses carrier proteins ie cytochromes to pass e and H from NADH amp FADH2 to 02 making H20 and generates a protein gradient chemiosmosis across the inner mitochondria membrane ATP Synthase The enzyme of the inner mitochondrial membrane that passively carriers H back into mitoplasm and makes ATP directly Glycolysis Key reactions Substrate level phosphorylation occurs twice Redox reaction involving NAD Reaction paths investment phase amp payoff phase Lecture 14 Bioenergetics and Cell Metabolism 10O62014 Eii 4EFtmr IrItraEsTrlilElliT up l lASiE EllulensE two V J geanp EuruteauatrFizi39r IiFF PHASE 4 ADP q q q quotThe El Pyruivme Ell1ticusa 0 p 2 Fyrru1rata 2iltgl239J 2 A1P 2 j3y 2 ATP m 2 IltilillD Io 2 Hl i i 2H 2 1quotquot quot6 u ll 1 392 lquot39n39i xi 11 riI us I rquotnL Fates of pyruvate if anaerobic alcohol fermentation amp lactic acid respiration If aerobic pyruvate dehydrogenase Krebs cycle Fate of NADH holds captured e energy Some cells use it in the mito membrane which is impermeable to NADH creates cytoplasmic and mitoplasmic pools Purpose is to move electrons captured into cytosolic NADHc into mitochondria Oxidative phosphorylation amp electron transfer chain The coupling of oxidation substrates e to the phosphorylation of ADP to make ATP most of the energy of glucose s bonds is now carried in NADH and FADH2 These series of electron carrier proteins occur in 4 membrane subnits NADH reductase succinate dehydrogenase cytochrome reductase cytochrome oxidase Chemiosmosis amp ATP synthase Creation of a hydrogen ion gradient H by e flow through the ETC and make ATP Review Lecture 14 Bioenergetics and Cell Metabolism sugars p ecide acids Fe39I lquotr pcilzls 0a Sub refes E lycel39feiSl l rlele Cycle ETC 5 eyn ll1t1 e ere Llnirelreel he tells HEB anl energy NADHl FlAlDrlgl 5 ATP 1 F39rp lLlr39l39s 4 pnrf DF pmceee is Anner39ebie deeen 139 require 02 EL3 quot 6lL 39luquot5I5 5 H includie uleehel 31 lm39l39ne fermen139e39l39i7er1539 Weneerp bi39c reefpim1ripn Krebs ele freqluiree 1 DE gl yeely5 i39e 5 purl is Aerobic E 0I llleecfipn wpee i39mlud e exid39equotl39ien5 redquotuc1ripne 5ubera1re level jphesfpherye139i39en5 clecerbp qrl u1rienSl eeyln ilen 5 hyrdrelyeis pr d e pha5 phnr3rl nian l n l39hase P Energy ca p139ulr39e is via el ee39l39rnn fran5Fer39e gred39i39en1395 prpfan pumps 5 I Regulefipzn is by Feedback inhibi139ian 5 alliasfepic maduIe39l39i39an hue hpr ucfekineee of key enzjrme 3 I1n39racellult1r39 lemfpurlmene39lipn l gl yeelr539i e pcculrs in Hue erlrep n5m Krebs C yrel e is masfly in H1e l39lquotll39139nlfFIll39ZI5 v l39l39l of mifachelndrin ETC is in fhe crie139ee mernbreneS pf rni 139echend39r39in ll 39melboli39c pefhwuye in elle quot quot quot W s chm pmceee ie een139r39al I IfE aquot39 la 1 IUEMB NIrhp5nn Mefabellle Pafh 10O62014 Lecture 15 Photosynthesis 10O62014 Photosynthesis autotrophic metabolism Photosynthesis is a light driven phosphorylation ADP P lightATP Autotrophic metabolism occurs in organisms which produce all their organic nutrients from inorganic materials through conversion of light energy into covalent bond energy Chemotrophic uses oxidation of small inorganics phototrophic uses light energy to make organics Cellular process occurs in living cells prokaryotes bacteria cyanobacteria blue green algae and eukaryotes all plant cells with chloroplasts Why do animal cells not photosynthesize Chlorophyll vs hemoglobin Molecular processes within photosynthesis Capture of light energy via pigment molecules chlorophylls and accessory pigments ie carotenes and phycobilins Redox reaction Includes photolysis splitting of water Captures e into cytochromes via plant ETC like carrier proteins It produces oxidizing power O2 and it produces reducing power NADPH Cells have separate pools of NAD cytoplasm and mitochondria and NADP chloroplasts Produces ATP via photophosphorylation Couples e transfer to H gradients amp ATP ADPPATP Reduction of CO2 to CH20 Source C e donororganic C oxidized donor 2 fundamental reaction mechanisms of photosynthesis light reactions photochemical reactions molecular based The molecular excitation of chlorophyll by light results in a charge separation across a membrane with generation of ATP via proton motive force H gradient amp reduction of NADP via an ETC to NADPH dark reactions thermochemical reactions via enzymes carbon dioxide reduction fixation occurs in 3 stages carboxylation reduction and regeneration Lecture 15 Photosynthesis 10O62014 Tihylakoid A Chloroplast 20l4 PEBYSOTI EULIDEIIOFE I116 The Chloroplast morphological basis of photsynthesis Leaf cross section Chloroplasts Vein palisades 1 2 quot Mesophyll x 39 spongy p Q Chloroplast Ivlesophyll NP NP ceII P Outer quot membrane Intermembrane Ia space 20 Mm Inner membrane 1pLITI Plastids double unit membrane bound organelles classified by pigment content and derived from Proplastids in meristematic undifferentiated cells give rise to all other plastids Leuooplasts Amyloplasts synthesize and store starch Aleuoplasts contain stored protein crystals Elaioplasts contain oil and fat globules fat biosynthesis Lecture 15 Photosynthesis 10O62014 Chloroplasm stroma contains Pyrenoids starch coated protein granules 70s ribosomes prokaryotic size naked DNA to bacterial cells DNA highly supercoiled amp repetitive enzymes of CO2 fixation and liquid droplets Pigments of Photosynthesis Accessory pigments any non chlorophyll pigments that absorb light carotenoids and phycobilins Chlorophylls abcd etc embedded in thylakoid disk membranes Light absorption in photosynthesis Electromagnetic spectrum directly absorbing Spectroscopy retracting Absorption spectra plot of amount light absorbed vs wavelength Action spectra plot of physiological activity 02 released vs wavelength Molecular excitation of chlorophyll absorption of light energy blue amp red light results in electrons being excited into higher orbitals Fates of absorbed energy photo excitation Reradiates as vibrational heat Reradiated as fluorescence Reradiated as phosphorescence slower far red light reemission Induced resonance vibrational e excitation is passed Photoionization takes part in photochemical reactions electron is passed to an acceptor ionized chlorophyll Light reactions photoionization take place in Photosystems complex protein and pigments that catalyze photosyntesis Includes chlorophylls reaction center molecules and primary e receptors Has two photosystems PS1 and PS2 PS1 captures e into coenzyme NADP making NADPH PS2 splits water photolysis releasing O2 and H Photosynthetic ETC path of e in photosystems Non cyclic ATP NADPH and cyclic only ATP Dark reactions take place in Lecture 15 Photosynthesis 10062014 the chloroplasm stroma consumes the ATP and NADPH made in light reactions Reduces CO2 into CH2O sugars C3 Pathway Calvin cycle known as this because the first molecule made is a 3 carbon carbohydrate 1CO2 5C RuBP rubisco23C Sugars It is the reverse of reactions of glycolysis C4 Pathway 1 CO2 PEP 3C combine into 4C acid OAA in mesophyll cells 4C acid breaks down into PYR 3C CO2 in bundle sheath cells amp this CO2 is now fixed into CH2O in the Calvin cycle as described above These are pathways to make sugarl Lecture 16 Cell division 10O62014 Key concepts of the cell cycle The CELL CYCLE 1 asexual cell division results in genetically identical 2 the 3 phases of life cycle of a cell are a lnterphase G1 S G2 b mitosis nuclear division c cytokinesis 3 the cell cycle is regulated by regulatory kinase active proteins and passes through Checkpoints Genetics and development Cell division physical basis of inheritability Mechanisms of cell reproduction egg cells and sperm cells Cells reproduce identically yet with variations Cell differentiation how one cell becomes different from another Differential gene activity genes are active at different times Totipotency and cloning exact genetic copies of cells Methods of cell reproduction Fission binary split into 2 equal halves Budding outgrowths detach into a new organism unequal split Mitosis asexual identical genetic copies cytokinesis Lecture 16 Cell division 10O62014 Meiosis sexual produces sperm and egg cells with 2 chromosome number and new gene combinations Mitosis asexual reproduction cell cycle Results in copying and equal duplication of parental ce s DNA and the equal division of chromosomes into 2 daughter cells Cell cycle life cycle of a cell has 3 stages lnterphase period between successive cytokinetic divisions of a cell Has 3 parts G1 before S DNA synthesis and G2 period after S Mitosis nuclear division phase separation of duplication of chromosomes Cytokinesis physical division of cell into two parts BWst g as a Mitosis calar sumanus In asiirmatian Ililitasis Plquot39lZI39Fl39hI E Clil39I1 Ei l aiEi39iIiqi 113 V an A n 39 1 u I 2lquotLr tlt39I39ttZl39l39lr1 carndsnsas lrlta chaamasamas animatian mmm Pramstaphasa altr39a masa39ms l39U39l lquotquots attach ta lsinataclaaras Fig 12 sash ltamalag has 2 shrarnatrials ME39l39ElPl391EIE lZaa1taiHiti39aitig391II 239 AaA 1 i ilI slwamasamss align at esqu39atar Fig ltaquotmal ags align inaaparndsntltr at sash athsrquot Anaphss g p MT attacltaazl ta lFnstasharr s htquotamatids firgt29 H l arts pulled apart 5 pal ss n fatrs2 apart Tslaphass at appasita pales at calls as cytak inssis starts ax animal calls 5 cantaacarl alas anian raat ti calls daujgalttar 39alls fasrm by syrtarkltnss is aniart t sls next mitasis aaimatsian EzialFliit anvil atian am itasris E quot 3 quot Stag as ampFi39aviaw Genes occur in the chromatin of the nucleus which condense into chromosomes visible only during mitosis Humans have 46 chromosomes 23 homologous pairs 23 maternal chromosomes and 23 paternal chromosomes Control of cell division and the cell cycle regulated by growth factors proteins that promote cell division MPF mitotic promoting factor complex of two proteins cdk cyclin MPF is a kinase enzyme that switches onoff target cell cycle proteins by phosphorylating them adding a phosphate group Lecture 16 Cell division 10O62014 cdk a cell division control protein cyclin dependent kinase active only when bound to cylcin cyclin a protein who varies cyclically when in high concentrations binds to cdk and makes MPF favors mitosis promotes entrance into mitosis from the G2 phase by phosphorylating multiple proteins during mitosis including one that leads to destruction of cyclin itself growth factors are regulated at critical points in mitosis Lecture 16 Cell division 10O62014 Meiosis sexual cell reproduction nuclear division phase of sexually dividing cells Key concepts 1 Fertilization and meiosis alternate in sexual life cycles 2 meiosis reduce number of chromosomes present by one haf from diploid to haploid 3 meiosis allows new combinations of genes that did not exist in either parent 4 genetic variation is the result of sexual life cycles and contributes to evolutionary selection distinct differences between meiosis and mitosis 4 pmggeiny calls i1 1 E 1 41 139htLIIs E E VIi5lt IlT39l5 2 El LIghquotI39ElIquot39 telll5 unyr 391rhLt5 1 cell division ll ll imeinsiis ii ll ll uirtehnh number art chlnamn5umes swims f thr musme5 parent cell imeinsiis ii llli ll ll new iimbintItiuns rt games not in parents Pf ihrquotnmmsuimes sort l d lmlllf of each izatrher laughter EEIIE are genaticnlllly itdEnri cml intleitzisiis llll mitosis S lllIulHi it Fl ENE UEEHTE I litfiltlQ i lfl llli f 0 d illquotlquotIl39lIQl lt ill lflillli l r IEEEETE meiosis I EEQJITIS repvliiieatianenu miller39l15 line iris lltlurrmhar inl39 ns inutlludilnQ prrurphase imartaphaize eacsh including prrnphase matauphsasa arIElphEltE39 dl I2 Iiiiil ililr 1 IlquotI pI39i E EH Eflid l ll ph IIEa IEplIquotlEaEJE39 Strnapsls of a tures mutt amour ccuirs luirilnglipir 1Pi1H a i aallunig wiirth cmassill gi Wat h mt g u nm1ilE39lEar ctlmmatlids ra395urltlilngtll1a3rrIrata crmrumummas Iltltit iill ipIrs tiegather due to sitar chromattdl Eeheston HIL liIbvEf at Two each diploid Zn and rgem1atirallifgr Fm r Each hiapIlia d tin eantailining halt tits many tzhmmaasom s laIlJ f llEiquot cells ilv l iilti vall to the parant EEIAII as the v sell IEI39tTlEillll1iE39ll li rdli erant them the mntanit and ganiEllc EiBIi I and frum each other G m lilfl Hole in the Enables muiittilcelilTular dullt ID arisa fimm Ff dlll i gaimetas iI39E39dlll IEE nrumbar f39Ehif tl139li E mE l halli art7lI39trtat body EyIgtIt pirxndums cnellils tor girnwtlti rapallzn and I39I39IIl39quotl39Idllll392 gzerliatltlt valrtnhilllttyr amiuziitrgi the gametes am In some sumIn5 asmtuall rrtmmduetI39an Lecture 16 Cell division 10O62014 George Arlene O Sandra Tom Sam Wilma Ann Michael Carla Daniel Alan Tina Mendelian Genetics provides I a mechanism to explain the Christopher inheritance of this trait uvu L J 39 nc Modern interpretation of Mende s hypothesis which is scientifically testable particles are genes entities definable in molecular terms represented by alphabetical taxonomy Aa Bb etc Upper case is a dominant trait and lower case is a recessive trait A trait as a shape may have different morphological forms called alleles which is a gene that codes for different forms of a similar protein Alleles occur on chromosomes at a specific place known as a gene locus Some alleles mask expression of others dominant and recessive allelic traits Recessive traits disappears in the F1 generation and dominant traits do not disappear in the F1 generation Each individual posses only 2 alleles for a specific trait thus RR homozygous dominant only 1 allele round Rr heterozygous dominant allele round rr homozygous recessive both alleles to be wrinkled Mendenial Monohybrid Genetic Cross Punnett square V3YE Y Yy Yy Y V3 V3 results of a monohybrid cross phenotype appearance 3 round to 1 wrinkled genotype allele makeup 1 Rr to 2 Rr to 1 rr Mendel s Law of Independent Assortment a dihybrid cross demonstrates principle of independent assortment which involves 2 characters or traits in which a new combination of traits not exhibited by either parent are seen parentals progeny look like parents Lecture 16 Cell division 10O62014 Crossing over during meiosis will allow one to map position of genes Mapping frequency of cross over exchange is proportional to relative distance between 2 genes linked vs unlinked for recessives ry linked or not all gametes will get same alleles crossing over homologous recombination the process by which two non sister chromatids paird up during synapsis of meiosis 1 exchange equal distal portions of their chromosomal DNA Frequency of crossover exchange 17 Proportional to relative distance between 2 linked genes the greater the frequency the farther apart 2 genes are 1 crossover frequency 1 centiMorgan
Are you sure you want to buy this material for
You're already Subscribed!
Looks like you've already subscribed to StudySoup, you won't need to purchase another subscription to get this material. To access this material simply click 'View Full Document'