University:
Mississippi College
Course:
BIO 305 | Cell Biology
Academic year:

2022
Views:

14

Pages:

2
Author:

Abby D.

4.1 Notes/TB-Chaptercells- membrane enclosed structures that cell Theory- - three componentare capable of producing other cells,cells are the fundamentalunit of lifeCytoplasm-everything in the cell w/oLiving organisms are compsthe nucleus.water inside, otherof cellsSubstances.cells come from pre cells.determine the cells structure and function.Cell membrane- keeps the internal chemicals of a cell + which helpslife functions different from the chemical composition outside thecell.Structure and functions of membrones are similar betweenorganisms.Biological membrone Characteristicsdetermined by the chemical properties of its lipid and protein.phospholipid bilayerproteins embedded in it or attatched tuiton the outside or inside.not a solid,unchanging structureThey move laterallyFluid Mosaic modeldescribes it as random movement"fluid" and the seperation of the proteins and lipids "mosaic"membrane proteins integral,anchured and peripheralPhospholipidsmajor lipid component of biological membranes.thin bilayers (8nanometers) thickphospholipid headshydrophillicreacts wr the H2O environment.phospholipid tailshydroprobic P reacts with each other on the insideaccts as a barrier prevents diffusionof polar molecules and ions.IF an4Fatty acid chain leng th can differ Number of carbon atomsdegree of consaturation CH of double bunds in their Fatty acidsin the phosphate group presentsaturated fatty acids - no double bondsgood for packingof phospholipids"Kinks"in unsaturated by double bondsless packingless fluid membronesGlycolipidscan alter membrane fluidityL impobes phospholipids bond w one another to form Van derWaals Interactions move laterally weak bondscarbs associated M membranes attates to liptosglycolipdsglycoproteins -or to proteins 3 (few carb residue)Membrane Fluidity imp. factors in PnospholipidsLipid Composition- - longer fatty chains havemore bonds togetherthan Shorter chainslower fluidity.Cholesterolalter interactions and membrane fluidity,ahightemp.decreases fluidity.Phytosterols - In Plants similar Structure to cholesterol Gmodifies fluidity(lower)Temperature- fluidity declines in cold conditionsmovesslowlyalters function OF membrane (increases Flaicility)ex: fingers numb after contact W ice, blocks off nerveactivity.LDIncoldertempsaturated can be replaced tounsaturatedIncrease fluidity - in animals during colder monthsless saturatedProteins are in membranes1 protein molecute for every 25pnospholid molecules.Mitochondria - energy production -D 1 protein for every 5 lipidsmyelin -1 protein for every 70 lipids.