Cell Structure and Membranes

4 cell structure membranes lipials proteins move laterally through membrane hydrophobic interior prevents diffusion of polar molecules through membrane Membra...

4 cell structure membranes lipials proteins move laterally through membrane hydrophobic interior prevents diffusion of polar molecules through membrane Membranes differ in chain length saturation polar groups nniais EE slower movement longer chains less fluidity Degree of saturation more double bonds more fluidity freeze that increases rate of diffusion 59sassfrition Temperature colder temp less fluidity some organisms alter composition double bond in cold enviro Membranes contain proteins proteins varies chloroplasts mitochondria have Integral membrane proteins  at least embedded partly Transmembrane proteins extend through bilayer c CP outside membrane could have diff functions on inside Peripheral membrane proteins only touch hydrophilic surface of membrane Anchored membrane proteins lipid groups to calently attached to fatty acids or anchor protein to membrane permonately attached Flycolipid carbohydrate attached Torport faces out Flipid fatty yup jihair Copotein protein w attached oligosaccharides 8 12 sugars normally carbonate Proteoglycan Toteinw covalently attached EI polysaccharide chains  rotein 4.2 p Selective permeability doesn't allow all substances to through pass of more ways transport passive no needed energy active need input of energy Diffusion movement of particles toward a state of equilibria from high to low concentrations 2 distance t 2 diffusion constant diffusion fast for short distances not good for long Things that affect diffusion size smaller molecules diffuse faster diffusion temp of solution temp concentration gradient faster diffusion area distance area to diffusion In diffusion of each a complex solution multiple solutes solute depends only on its own concentration  higher concentration inside cell causes solute to diffuse out vise versa simple diffusion Oz CO2 or smell nonpolar lipid solvable molecules can cross membrane unaided Isotonic equal solute concentrations 1Ectoni L.hn solution has lower solute concentration has higher solute concentration if1flution ons solute Facilitatedidiffusion passive transport of solutes down gradient w help of integral transmembra proteins ex aquaporin ion channel Ion channels Tostgated a open up when a stimulus causes the protein to change shape ex.li satedsve gated Active transport ATP needed to move substances against concentration gradient Twotypes active trans involves direct hydrolysis Primary ex Sodium potassium pump one ATP moves tw Kt 3 Nat  Secondary active energy stored in trans uses electrical gradientsconcentra which or are established by primtranspo Nat K gradient of Nat then passive pump create con diffusion of Nat back into cell provides for energy glucose transport 4.3 Lxocytosis moves materials out of cells I as macromolecules into eukaryotic cells Endocytosis brings 8 Foot hagocytosis engulfs large particles or a cell called a phagocome Pinocytosis vesicals smaller in fluids are bring dissolved substances Receptor mediated endocytosis brings specific large molecules into cell via specific receptors 4.4 diffusion moves most molecules around the cell some cells have follings to increase surface area Cytoskeleton meshwork of protein filaments support maintain cell shape maintain position of organelles particles in cell can more organelles or particles in cell interact w structures outside cell to keep it in place 3 types of cytoskeletal protein filaments 1 Microfilaments actin polymers made from actin monomers attach at plus end can shorten or quickly to assemble disassemble cytoskeleton lengthen help maintain cell shape movement to side walls of cytoplasm cytoplasmicsteaming actin filaments motor protein myosin responsible for cell contractions 2 Intermediate filaments IF made of fibrous proteins organized into tough repelike assemblages also help maintain shape more permanent than other filaments  not found in cells but in plant animal cells hast soluble components of cytoskeleton NOI polymers 3 Microtubules Kinesin polymers made up of tubulin protein microtyble made of alpha beta agg microtubules have a hollow core B.EE imer have pos neg ends dynamic instability d kinesin walks microtable ATP along releasing ADP accepting hydrolising each stem Extracellular matrix absorbed water to form mix of collagen gel like proteoglycans hold cells together in tissues part of cartilage skin bone help fitter material passing between different tissues ex kidney help orient cell movements during tissue repair Integrins connect cell membrane to extracellular matrix reversible binding sites connect to microfilaments or IF inside cell collagen in the extracellular matrix 3 types of cell junctions Tight junctions prevent substances from moving between cel ex in digestive track Desmosomes hold cells w stable protein connections but permit materials to move around them very small space ex in skin Gap junctions channels that run between membrane pores allow materials electrical signals to pass 4.5 Prokaryotes have to nucleus or membranenclosed internal compartments do use protein based capsules to separate substances Encatpsulin nanocompartments enclose single protein a ex ones that break down toxic substances some prokaryotes cyanobacterial have internal membrane for photosynthe DNA singular circular molecule in the nucleoid Prokaryote Ribosomes contain proteins RNAs also site of protein synthesis into peptide sequences Eukaryotes have nucleus each organelle specific role compartmentalization allow for regulation efficiency Sntain cell DNA site of DNA replication RNA transcription  pore unclear envelope Endomembrane system Tillison 0 0 armed 12HA it tRIV E ifi Isataonedonit protein synthesis 2 Smooth er interconnected sheets t tubules lipid synthesis i Shett i bemotithcant interact w phosphate vesicles move proteins Golicomplex g to solsi functionally linked w ER proteins so rough and salsi to O in vesicles get modified Ég resides fuser Cis golgi proteins exit solgi in resides trans that bad off medial otomy.mn lisosomor fusion of vesicles post solsi that contain enzymes that hydrolyze macromolecules 2types Primary originate from solsi Secondary vesicles formed by phagocytosisthat has been fused w primary lysosome a Non endomembrane system cris creates h gradient Y Ef harvested a stored as ATP has DNI ribosomes tRNA some folded into cristae for t surfaccreato MATP profginimmmembrane Plastids Chloroplast Tohave circular DNA 2 divide autonomously two membranes plus thylakoid membranes light energy chem energy carbohydrates synthesized in stroma sugars Peroxisomes break down Féroxides V.IEy plants fa convertstorediinsmd Y tt me funsi store waste toxic compounds Structure for water enters through osmosis creatingturgorpressure plant cells Reproduction in flowers