Mdule 2 Chapter 4 Anatmy f the Cell The Prkarytic and Eukarytic Cells Prkarytic cells and eukarytic cells Cmpsed f carbhydrates, prteins, nucleic acids, lipids Perfrm f chemical reactins Differences are primarily in internal, external Shapes Average size: Mst bacteria are Maintain thrughut lifetime A few are Adpt Mre difficult t based n shape alne Three basic shapes Cccus Bacillus Bacillus à Bacillus à Spiral Have twists Vibri Spirilla Helical, shape Rigid bdies Spirchetes Helical, Other shapes include: Star shaped Rectangular, flat
Structures external t the cell wall Glyccalyx A plymer f cell wall Tw general types f glyccalyx Capsule Slime layer Can be imprtant in cntributing t (ability t cause disease) allws cell t attach - Capsules prevent Flagellum, flagella Lng appendage(s) that Allws fr Ability t Outside f Made f Arrangement f flagella Peritrichus Mntrichus Lphtrichus Amphitrichus Atrichus Taxis mvement frm envirnment Psitive taxis envirnment Envirnment called Negative taxis frm envirnment Envirnment called Envirnment includes chemicals, light Mvement twards light taxis Mvement away frm chemical taxis Axial filaments Bundles f that cell AKA Uniquely in cause cell t mve in Fimbria, fimbriae appendages Nt used
Fimbriae allw fr Neisseria gnrrheae sticks t N, n Pilus, pili Used t between bacteria Prcess called Als can be used fr The Cell Wall Surrunds Bacterial cell wall made f Peptidglycan Plymer f (NAM r NAG), frms backbne Linked by Arrangement f peptidglycan used t classify bacteria int 2 grups bacteria bacteria Gram-psitive cell walls ; layers f peptidglycan next t cell membrane acids - nly in Gram-psitive cell wall acid links t teichic acid links t Gram-negative cell walls layer f peptidglycan membranes In between uter and inner ( ) membranes Outer membrane cntains (LPS) Prtectin frm, immune system Prvides t is an frm thrugh uter membrane Atypical cell walls Acid-fast cell walls Like bund t peptidglycan frm immune system Fund in Archaea
Wall f (lack ) Mycplasmas Lack in plasma membrane, prvide The plasma membrane Thin layer, enclses f cell Cnsists primarily f Arranged in parallel rws called heads n tw surfaces f membrane tails in f membrane Membrane is as viscus as within membrane perfrm varius functins Channels, structure, transprt Phsphlipids and prteins are Referred t as fluid msaic mdel Functins f membrane: barrier fr materials int and ut f cell mlecules can pass barrier pass t big t squeeze thrugh pass n phsphlipids repel ins mlecules (ie xygen, carbn dixide,) pass passes thrugh channels ( ) prteins allw specific mlecules t pass The mvement f materials acrss membranes In rder t generate energy, fd must crss membrane Mst resurces are t crss membrane prcesses Mlecules mve frm an area f cncentratin t area f cncentratin the cncentratin gradient Requires prcesses Mlecules mve frm an area f cncentratin t area f cncentratin the cncentratin gradient Requires Passive prcesses 3 mechanisms: Simple diffusin Facilitated diffusin Osmsis Active Prcesses (1 mechanism) Active Transprt
Simple diffusin Net verall mvement f mlecules frm an area f cncentratin t area f cncentratin Equilibrium the pint when Simple diffusin acrss plasma membrane imprtant fr small mlecules like, Facilitated diffusin Similar t simple diffusin, ie the cncentratin gradient Uses t crss the membrane Mlecules cannt crss membrane Osmsis Mvement f acrss a membrane frm an are f cncentratin t and are f cncentratin Osmtic pressure the pressure needed acrss the membrane Imprtant fr cell t balance smtic pressure Tnicity - measure f cncentratin in a slutin relative t a membrane Slute cncentratin f ( ) cmpared t inside f (acrss the ) Measured as Affects transprt f ( can t crss membranes) Istnic slutin - slute cncentratin f a slutin is t the slute cncentratin in a cell Hyptnic slutin - slute cncentratin f a slutin is than the slute cncentratin in a cell Hypertnic slutin - slute cncentratin f a slutin is than the slute cncentratin in a cell Active Prcesses Smetimes cell needs t mve mlecules Cell uses Requires
Inside the prkarytic cell The Cytplasm is the substance f the plasma membrane Cntains: - fluid and disslved prtin f cytplasm, rganic mlecules, inrganic ins Specialized structures Nucleid The area that cntains the Called the Takes up inside the cell The prkarytic ribsme Respnsible fr Ribsmes are cmpsed f prteins and (rrna) Bacterial ribsmes ( ) cnsist f tw subunits: Small subunit; subunit Large subunit; subunit S a reference t size Inclusins used fr varius purpses Can include stres f, prvide varius Endspres cells Resistant t desiccatin ( ), heat, - endspre frmatin - return t vegetative (grwing) state The Eukarytic cell Typically, structurally mre than prkarytic cells The plasma (cytplasmic) membrane t prkarytic membrane Cmpsed f a bilayer Includes embedded in the bilayer Eukarytic plasma membrane cntains Nt fund in prkarytic cells (exceptin: Sterls are fund in which prkaryte?) The cell wall and glyccalyx Cell wall is generally than prkarytic cell walls, nt peptidglycan Plants, algae have cell wall Fungi have cell wall Many eukarytes have cell walls Sme eukarytes have Help strengthen cell surface, attach cells tgether
Cytplasm Everything, utside f : prtin f cytplasm Majr differences: Presence f Prvides supprt, shape, mvement (ie, metablism) that are fund in Organelles Structures with specialized functins Nt fund in prkarytic cells Nucleus: Strage f DNA Ribsmes: 80S (40S + 60S); different size cmpared t bacteria; same functin Endplasmic Reticulum (ER): Synthesis f mlecules Glgi cmplex: Transprt f mlecules Lyssme: Degradatin & recycling f mlecules Vacule: Strage f mlecules Mitchndrin: ATP generatin Chlrplast: Phtsynthesis Perxisme: Degradatin f txins Chemtherapy Use f t (kill r stp grwth f) Antimicrbial drugs display - acts within withut substance prduced by that inhibits grwth f ther micrbes spectrum Affects spectrum Affects cells harder t inhibit Prtected by Drugs must be and t pass thrugh Penicillins (Beta-lactams) with similar mechanism Penicillin (ns), ampicillin (bs), xacillin (bs) Prevent synthesis f Weakens ; cell ( ) Affects nly cells Plypeptide antibitics Bacitracin Inhibits bacteria
nly Vancmycin Very narrw (Staphylcccus) Last effective antibitic against Methicillin resistant Appearance f vancmycin resistant (VRE) a cncern Antimycbacterial antibitics layer mst chemicals Isniazid inhibits f myclic acid Used in with ther drugs Prtein Synthesis Inhibitrs Prkarytic ribsme frm eukarytic ribsmes (30S + 50S) vs (40S + 60S) antibacterial target Chlramphenicl binds t inhibits activity (bs), simple t make (cheap) used nly when necessary Tetracyclines prevent trna binding t (very bs) Can and inhibit intracellular pathgens Nemycin changes Shws serius side effects, s nly