Chapter 6: A Tour of the Cell. Technology to study cells. light microscopes – pass visible light through specimen and lenses. magnification – ratio of image size to actual size. resolution – clarity of image; minimum distance between two distinguishable points.
microvilli in intestine
increases surface area for absorption
helps in synthesis of secretory proteins (proteins made for secretion), especially glycoproteins – proteins that have carbohydrates on them
Also the membrane factory of cell; makes new membrane for itself that becomes vescicles; these eventually become part of cell membrane
vescicles from ER fuse with cis face and empy contents into lumen of cisternae
– modifies carbohydrates
– alters protein structure
vescicles bud off trans face and carry contents to cell membrane for export or to different parts of the cell
Cherry-red spot on retina identifies Tay-Sachs
– membrane: tonoplast
– outer membrane smooth
– inner membrane is stacks of sacs called
middle lamella – between primary cell walls of adjacent cells. Rich in pectins (sticky polysaccharides). Glues cells together.
fibronectin – another glycoprotein in the ECM that binds integrins on cell membraneintegrins – proteins that span the cell membrane and transmit info on changes outside the cell to the cytoplasm
desmosomes(animals) – fasten cells together into a strong sheet. Like rivets.