The Cell membra-WPS Office.docx

**[The Cell membrane]** **[Introduction]** \_ cell is the building block for all living things. \_ perform necessary maintenance recycle parts , dispose of wastes and adopt to change in its environment replaced itself. \_ differ in size can be large ( froge\'s egg) or very small to see by naked...

**[The Cell membrane]** **[Introduction]** \_ cell is the building block for all living things. \_ perform necessary maintenance recycle parts , dispose of wastes and adopt to change in its environment replaced itself. \_ differ in size can be large ( froge\'s egg) or very small to see by naked eye ( light microscope) \_ some of are single cell ( bacteria). \_ can still for billions of years to a wide array of environment and functional rules (nerve cell long thin extension can reach for meters and transmit single rapidly). \_ plant cells have rigid (closely fitting brick shape) outer layer providing structural support. \_ muscles cells are long tapered provide contracting and relaxing biceps. \_ Cells are small ( needs for fast , easy , food) must are between 1 and 100 micrometer in diameter. **[Types of Cell ]** \_ Classify according to how Genatic material is packaged into : A\\ **Prokaryotes** \_ the Genatic material not separated from the cytoplasm of cell , single cell and small. \_ consisting cytoplasm surrounding by plasma membrane no distinct interior compartment. \_ no true nucleus,  ribosomes not surrounding by membrane. \_ metabolic function carried out by prokarute found in membrane. \_ unicellular and have cell wall ( structural support,  barriers against outside forces) ,  some of have capsule ( stick to surface). \_ are between 1 to 10 micrometer in diameter,  the first type of cells in earth. \_ DNA forms a circular molecule with ribosomes. B\\ **Eukaryotes** \_ Genatic material found in nucleus,  single or multicellular,  all plants and animal cells are eukaryotes cell , organized into complex structures \_ it\'s name come from the Greek means true nucleus \_ nucleus ( is a membrane closed organelles that contain DNA) , the DNA organized in one or more linear molecules Chromosome **[Cell Structure]** \_ all living organism contain different type of cells ( function maintain a proper homeostasis in the body and environment of body in constant state \_ common things between differ types of cells : 1- cell membrane 2- cytoplasm 3- ribosome 4- DNA **[Plasma Membrane]** \_ separate internal environment of cell from outside environment \_ allow for certain molecules pass into and out of cell ( selective permeability, semipermeability ) \_ act as attachment point for bath , is a Lipids bilayer ( double layers of closely packed Lipid molecules. \_ contain Lipids (phospholipids and sterols) and proteins( helps channels). \_ cytosol and extracellular fluids are made of water **[Membrane Protein ]** \_ protein molecules attached to cell membrane \_ the protein maybe glycoprotein \_ provide mechanical support for membrane \_ function: as anchor for integral membrane proteins. \_ Classify into 2 groups based on how Proteins attached to membrane : 1-**Peripheral Membrane Protein** \_ not embedded in membrane cytoplasmic or extracellular side \_ associated more lossly with polar heads at inner or outer surface \_ have surface function enzyme specialized factor transmit transmembrane signal 2- **Integral Membrane Proteins** \_ embedded with plasma membrane , act as cell receptor \_ function: transporting molecules across the membrane \_ Classify into: 1\\ **Transmembrane proteins**    found in all types of membrane 2\\ **Integral monotopic proteins**    permanently attached to membrane from only one side **[\*Cell Membrane Protein]** \_ found in Lipid bilayer \_ passage way to allow substance to cross membrane \_ nit fixed in position ( crowded with protein or sparsely distributed) \_ contain : A\\ **Transporters** :- \_ selective membrane allow certain substance enter or leave cell ( channels or carriers) B\\ **Enzymes**  :- \_ carry out many chemical reactions on interior surface of plasma membrane C\\ **Cell Surface Receptors** :- \_ sensitive to chemical messages,  act as antenna D\\ **Cell Surface Identify Markers** \_ carry cell surface maker that identify them to other cell E\\ **Cell Adhesion Protein** \_ cells use specific protein to glue themselves to one other,  or act like velcro or form permanent bond F\\ **Attached To Cytoskeleton** \_ surface proteins attached to other cell are anchored to cytiskeleton by linking proteins **[Transportation Across Cell Membrane ]** \_ separate cell from outside environment \_ 2 Types of transportation:- A\\ **Passive Transportation:** 1\\ **Diffusion**:- \- net of movement , transport substance from region with high concentration to region with low concentration, no energy needed **  High \-\-\-\-\-\--\> low** 2\\ **Facilitated diffusion** \- some molecules are polar can not pass through the phospholipids bilayer ( nonpolar) they pass through channels ( insof it is polar) 3\\ **Osmosis** : \- movement of molecules from region with high concentration to region with low concentration through similar permeable membrane,  determined by comparing total solute concentration B\\ **[Active Transport]** : 1\\ **Bulk passage into and out of cell** \_ **Endocytosis** :- plasma membrane extends outward and envelope food particles Types: 1- **Phagocytosis**: fuse with lysosome for digestion 2- **Pinocytosis**: non specific processes 3- **receptor endocytosis** : triggered by molecular signal \_ **Exicytosis** discharge of material from vesicles at cell surface , provide digestive enzyme and secreting hormones  2\\ **Active Transportation Of ions and molecules:** \_ process requires the expenditure of energy typically ATP \_ Involves highly selective protein carriers within the membrane \_ the molecules used in synthesis of DNA,  cells may need to move molecule against concentration gradient from : **Low \-\-\-\-\-\-\-\--\> High** \_ shape charge transport solute from one side to another (cost = ATP) protein pump