The cytoskeleton is a meshwork of protein filaments that provides support and

The cytoskeleton is a meshwork of protein filaments

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The cytoskeleton is a meshwork of protein filaments that provides support and movement Cytoskeletal proteins (Actin, myosin, tubulin and others) are responsible for cell movement and cell shape Muscle cells are special cells with exceptional cytoskeleton that allows for contraction ° Cell junctions (connections) Specializations of the cell membrane that attach neighboring cells and allow materials to move between them The cell is a complex and confusing place. And the ultimate explanation for it must be chemical and molecular February 20, 2015 The chemistry of life is the chemistry of carbon Carbon’s almost unlimited ability to bond to itself makes it possible to form macromolecules of great length and complexity ° Carbon chemistry can be understood in terms of functional groups: Amino, carbonyl, carboxyl, hydroxyl, phosphate, sulfhydryl Carboxyl groups are acids: H+ ion donor = organic acids o Carbon double bonded to oxygen and single bond to OH Amino: H+ ion acceptor = organic base ° The presence of similar chemical groups in two molecules tells us that they will have some properties in common (Example: amino and carboxyl groups in both of these molecules) ° Living things are based on “macromolecules”: No precise definition (MW > 1,000 d)
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Usually assembled from simpler subunits by the process of polymerization: o Monomer, dimer, trimer, tetramer, polymer If all the same, the polymer is a homopolymer If all different, the polymer is a heteropolymer ° Four major classes of biological macromolecules: ° Lipids Basis: hydrocarbon chain – made up of hydrogen and carbon Constructed from fatty acids Triglyceride (a lipid) – cooking oils Fats (lipids) are macromolecules that are waxy or oily and soluble in organic solvents (such as ethanol, acetone, benzene) Many lipids have water-loving and water-hating portions o Have polar heads (hydrophilic) o Nonpolar tails (hydrophobic) Making them particularly good at forming membranes  phospholipid bilayer, or membrane Stearic acid – a saturated fatty acid (maximum number of hydrogens for each carbon) Oleic acid – unsaturated acid (in the middle there is a double bond therefore we cannot have the maximum # of hydrogens) Linolenic acid – poly-unsaturated (tells us how many double bonds there are) ° Carbohydrates (sugars  polysaccharides) Have the general formula: (CH 2 O) n where n>3 o Glucose C 6 H 12 O 6 o When the linear form closes to form a ring, the position of the – OH group on carbon #1 determines if it will close in the α (alpha) or β (beta) form Glucose is a monosaccharide (simple sugar)… which can be joined to other sugars to form disaccharides – or polysaccharides Starch – a polymer of glucose o Tens of thousands of glucoses linked together
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o Starch and cellulose are both polymers of glucose. Monomers of starch are linked by α (alpha)-1,4 glycosidic bonds o Cellulose uses β (beta)-1,4 glycosidic bonds – oxygen is in β We do not have enzyme to break down β bond ° Nucleic acids (nucleotides  nucleic acids) Nucleic acids are polymers of nucleotides
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