The Cell Ch 2 14 01 2010 19 08 00 Robert Hooke early microscopists in 1665 discovered the cell by shaving a piece of cork and named it Used a simple microscope made the microscope by hand Anton van Leeuwenhoek first person to see living cells through algae from pond water Later observations lead to the idea that all living things have cells Matthais Schleiden 1804 1881 a botanist looked at plant cells Theodore Schwaan 1810 1882 a physiologist looked at animal cells Over a couple bottles of wine realized that both cells had nucleus Cell theory All organisms are composed of one or more cells Cells are only produced by the division of pre existing cells Cells are the smallest units that perform all vital functions Rudolf Virchow a physician studied human tissues studied pathology Came to conclusion that all living thing are composed from cells Two types of cells Sex cells germ cells that are derived from the testis or ovary Somatic cells all other kinds of cells Light microscopic compound microscope Uses a visible light source Some sort of glass a mirror Can magnify 1000x Electron Microscope Metal cylinder has a vacuum High power of current that displays the electrons Specimen is extremely thin and in something really hard like plastic so it doesn t vaporize away Cooling apparatus the reduce the heat Can magnify 100 000x Cell environment Plasmalemma thin membrane that separates the extracellular space from the inside o Phosolipid bilayer heads on the outside hydrophilic and tails on the inside hydrophobic Cytoplasm fluid medium inside the cell Extracellular fluid cations Membrane has two protein o Integral proteins through the membrane o Peripheral proteins either inside or outside the membrane Permeability the membrane controls what goes through and what doesn t Some just pores that let all through Some are specific and only let some through Involveds both active and passive processes Passive transpirt o No energry needed to complete o Simple diffusion Goes from high concentration to low concentration o Osmosis Same as diffusion but in water o filtration o Facilitated diffusion Active transport o Energy needed in form of ATP o Independent of concentration gradients o Involves transporter protein or carrier linked to an ATP motor o Endocytosis Brings ECF into cell with a vescile Pinoctosis fluids Phagocytosis engulfs foreign bodies into cell to break down and then remove by exocytosis Receptor mediated endocytosis Has coated vesicle and meet and fuse with a lysosome Uses what is needed and removes the rest Needs lignands Exocytosis removing ECF from the cell Cytoplasm combo if ICF cytosol limited by the plasma membrane look it up has organelles Two types of organelles Nonmembraneous organelles o Cytoskeleton element Form and structure of the cell Microfilaments Actin Anchor cytoskeleton to integral proteins of plasma membrane Microtubulues Hollow tubes that give shape but help with movement Intermediate filaments Stabilize position of organelle o Microvilli Finger like processes all the same length Increase surface area involved in absorption Contain actin Below glycoccyx o Celia Beat to move material over surface of the cell not move the actual cell Not dense but longer in length 9 2 arrangement of microtubules 9 along the edge and two microtubules in the center o Centrioles Important in cell division Organize tubules to exert traction on the chromosome Composed of nine sets of three microtubules Can kill cancer by destroying microtubules o Flagellum Like cilia but longer and move powerful Makes the cell mobile not the fluid it 9 2 arrangement o Ribosomes Composed of RNA Primary site of protein synthesis Exist in two forms Fixed on RER Free in cytoplasma in a string like formation Polyribosomes used to make protein inside the cell RER makes protein intended for use outside the cell RER must pass through golgi apparatus before released by exocytosis Membrane bound organelles o Surrounded by lipid membrane o Isolated from cytosol o Mitochondria Double membrane one within the other Outer is smooth like balloon Inner has cristae Has little bumps enzymes Makes ATP 95 Same cells have same number of mitochondria Can migrate from one cell to another Have own DNA can increase their own division and make their own proteins with their own ribosomes Evolved from symbiotic relationship Only not present in RBC ad terminal skin cells o Nucleus Has nuclear membrane associated with ER rough or smooth for easy transfer and protein production Nuclear pores Control what proteins are made and in what quantities Only present in eukaryotic cells not bacteria Two operations Transcription use DNA to make mRNA Translation mRNA move to cytoplasm to synthesize new proteins o Endoplasmic Reticulum Cisternae tube like chambers RER have ribosomes attached Protein secreting cells SER no ribosomes attached Make cholesterol or steroid compounds Synthesis storage transport and detox o Golgi Apparatus Never have ribosome and curved but look like ER Have transport vesicles on forming cis face closer to ER Transport from ER to GA And secretory vesicles on maturing trans face facing the edge of cell Transport from GA to membrane through exocytosis Functions Package material for lysosomes Create membrane segments Form secretory vesicles o Lysosomes Primary formed at GA and contain inactive enzymes Secondary when lysosomes reacts with something brought in by endocytosis and the excess is released by exocytosis Can recycle organelles Intercellular attachments Occluding junctions o Zonula occludens Tight seal blocks h20 or other substances b w cells Anchoring junctions o Zonula adherens Sheet like junctions that are linear Bw epithelial cells actin o Macula adherens More of a spot weld b w cells desmosome Like a button reinforce with metwork of intermediate filaments Communicating junctions o Gap junctions electrical or nexus junctions Prevent direct passage os signaling molecules ions b w cells Narrow channels connet adjacent cells Connect at connection either closed or open Often combo all intercellular attachements 14 01 2010 19 08 00 14 01 2010 19 08 00