All the quizzes are online Cell shapes and Sizes Squamous o Fried egg Flat o Line the esophagus and forms the surface layer epidermis of the skin Cuboidal o Squared egg o Liver cell Columnar o Columns with egg in the middle o Lining cells of stomach and intestines Polygonal o Bunched Fried eggs squished o EX Stellate o Splatted fried egg Starlike shape o Cell bodies of many nerve cells Spheroid o Planets o Egg cells o White blood cells Discoid o RBC s o In red blood cells Fusiform Spindle shaped o Whicker shaped o Smooth muscle cells Fibrous o Worms o Skeletal muscle and axons nerve fibers of nerve cells Cell size and basic components of a cell Human cell size o Most from 10 15 micrometers um in diameter Egg cells very large 100 um diameter o Light microscope Good but limited o Resolution of electron microscopes reveals ultrastructure Basic components of a cell o Plasma cell membrane made from proteins and lipids Forms the border of the cell Intracellular face o Inside each cell is the bottom The areas below and above the brown line 98 of molecules in plasma membrane are lipids o Phospholipids Phospholipid bilayer Two heads that like and don t like water o Cholesterol Can stiffen the membrane make it less fluid in spots Can also increase membrane fluidity by preventing phospholipids form becoming packed closely together o Glycolipid Contributes to glycocalyx More carbohydrate than liquid Helps catch things Micro organisms o Transmembrane Proteins 2 Membrane Proteins Functions of membrane proteins o Transmembrane Proteins Receptor Binds to chemical messengers such as hormones send by other cells Enzyme Breaks down a chemical messenger and terminates it s effect Ion Channel Constantly open and allows solutes to pass in the and out of the cell Gated ion channel Opens and closes to allow solutes through only at certain times Cell identity marker Glycoprotein Proteins for each cell that distinguish them Cell sorting Cell adhesion molecule CAM Allows cells to come together and stick Second messengers Chemical first messenger epinephrine binds to a surface receptor o Receptor activates G protein aka GTP binding protein G protein relays signal to acetylate cyclase which converts ATP to cAMP second messenger o Take one molecule and binding can affect 1000s are activated Amplification of a signal Membrane Transport o o o o Plasma membrane a barrier and a gateway between the cytoplasm and extracellular fluid ECF Selectively permeable Passive transport mechanisms require no ATP No energy needed Filtration Diffusion osmosis Active transport mechanisms consumes ATP Requires energy Carrier mediated mechanisms o o Extracellular o Cytoplasm Extracellular fluid ECF