Outline of Last LectureOutline of Current LectureCurrent LectureThe CellHow to Study:1. Observation:2. Microscopic Examination:3. Cell Fractionation:Cell TypesProkaryotic CellEukaryotic CellsNucleus:RibosomeEndomembrane System:Endoplasmic Reticulum (ER)Rough ERGolgi bodySmooth ERSmooth ERLysosomesPhagocytosisAutophagyApoptosisVacuolesPeroxisomeMitochondriaChloroplastCytoskeletonMicrotubulesMicrofilamentsIntermediate filamentsCell MembraneCell WallCell Cell JunctionsMembranesPurposeTo StudyStructurePermeabilityFacilitated DiffusionActive TransportCotransportLarge MoleculesBIO SCI 150 1st Edition Lecture 5Outline of Last Lecture 1. Macromoleculesa. Propertiesb. Carbohydratesi. Structuresii. Starchc. Lipidsi. Fatsii. Phospholipidsiii. Steroidsd. Proteinsi. Amino Acidsii. Structureiii. Denaturationiv. Functione. Nucleic AcidsOutline of Current Lecture 1. The Cella. How to Studyi. Observationii. Microscopic Examinationiii. Cell Fractionationb. Cell Typesi. Prokaryoticii. Eukaryoticc. Membrane, Wall, and Junctions2. Cell Membranea. Purposeb. To Studyc. Structurei. Permeability1. Kinds of Transportd. Large MoleculesCurrent LectureThe CellHow to Study:1. Observation:- colony growth- size, type and appearance- nutritional requirements2. Microscopic Examination:- Light magnification 1,500 resolving power 0.2 pm stain may be necessary to see biological structureso Brightfield = illumination passes through objecto Darkfield = illumination lights object against dark backgroundo Phase contrast = illumination passes light through object at an angle tohighlight boundary regions of different densitieso Confocal microscopy uses lasers and image analysis to visualizeonly a thin slice of an objecto Fluorescence uses stains that emit light when exposed to differentwavelength light. Allows different cell structures to glow withdifferent colors- Electron magnification 100,000 resolving power 0.1 - 2 nmo TEM: transmission electron microscope  electron beam is focused and passed through objectmost objects must be stained with heavy atoms to be detectedstain may be applied directly to structure, or sprayed at anangle to produce 3-dimensional image and shadowo SEM: Scanning electron microscope Subject is coated and electrons are focused and bounced off the coated surface, producing 3-dimensional image, wholeorganisms, cell fractions, freeze fractured cells, or large macromolecules may be visualized3. Cell Fractionation:Cells are broken and cell components are separated by physical orchemical means.- Centrifugation:o Velocity: Objects are centrifuged in solution, separation is bymass and shape. Objects with greater mass will movethrough the tube more quickly. More compact objectswill move more quicklyo Density: Objects are centrifuged in solution with heavy atoms,like cesium.A gradient of different densities isproduced along the tube and the objectwill move downthe tube until it reaches the point at which its owndensityis equal to the density of the surroundingsolution. The object will remain at that position. Thisseparates objects of different densities; size and mass areless important- Electrophoresis:o Size: Objects are separated by overall molecular weight, largerobjects move more slowly through the medium. Proteinsand Nucleic acids are separated and sized by thismethod.o Charge: Objects are separated according to the surface chargethey present. Conditions can be created to separateacidic, neutral and basic molecules. This separation canbe combined with size separation to produce a twodimensionalgel with the ability to resolve thousands ofdifferent proteins from a cell.- Chromatographyo Column: Objects may be separated by size, shape or charge orother properties. Separation is based on differentialaffinity of column material for molecules passed throughit. Applications range from simple size exclusion to precise DNA hybridization or antibody-based affinities.o HPLC: Separations are done at high pressures, numerousapplications including aqueous/organic solvent mixturesmake this a powerful separation technique.Cell TypesProkaryotic Cell - lacks a nucleus- Bacteria, blue-green algae- Divide rapidly,, doubling time of 20 min- smallest - mycoplasmas 0.1 - 1 pm- most - l-10 pin E. coli M l-2)o As the size of a cell increases the surface area / volume decreases- plasma membrane surrounds cell- cell wall- DNA - circular chromosome “nucleoid region”- Many import enzymes bound to plasma membrane, which may fold in- pili - attachment- flagella -- movement- ribosome - protein synthesis (antibiotics work here)- plasmids - mobile “mini-chromosome” may give antibiotic resistanceEukaryotic CellsNucleus:- size = 5 pm- nuclear envelope encloses nucleus- nuclear pore allows passage of large molecules to nucleus- chromosome (chromatin) DNA and proteino Information stored in DNA on chromosomes as genes contains: Work Order how many, when and where to make a protein Blueprint how to assemble and process a proteino 46 chromosomes in humanso M 50,000- 100,000 genes in humano Total length = 2M per cell- nucleolus - region in nucleus for ribosome synthesis and assembly- nucleolus organizer region (NOR) chromosome region with many genesfor ribosomal RNA (rRNA) in a rowDNA information in the nucleus is copied (transcribed) into RNA messengerRNA (mRNA).This travels to cytoplasm, joins ribosome, the site of proteinsynthesis, where it is translated into protein.Ribosome- Organelle made of RNA (rRNA) and many proteins M 80-100- 2 subunits, large and small- newly made: protein (polypeptide) exits thru channel in ribosome- Free ribosomes synthesize protein for inside cell, enzymes- Bound ribosomes synthesize protein that is passed into the Endoplasmico Reticulum (ER) where it is processed. Often these are secreted proteins.Endomembrane System:- Internal versions of plasma membrane which do specific jobs- Membrane is continuous and may break and fuseEndoplasmic Reticulum (ER)- network of sacs. cisternaeRough ER- protein processing, addition of carbohydrates for glycoproteins- important for function and secretion- breaks off to form transport vesicles- makes more membrane, which can fuse with plasma membraneGolgi body- Next stop for transport vesicles from rough ER proteins are processed here.o Cis Face - Receivingo Trans Face - shippingo Sorting - recognizes phosphate protein and sugar “tags”for direction to ultimate locationSmooth ER- Site of o lipid synthesiso carbohydrate