LIVING SYSTEMSA. attributes of living systems:a. reception and response to signalsb. capable of using an energy sourcec. capable of movement, development, and replicationd. are typically evolving via mutationsB. the flow of information:DNA  RNA  proteinssometimes RNA  DNA, but proteins NEVER  RNA or DNAORGANIC CHEMISTRYA. functional groups:alcohols, ketones, aldehydes present in carbohydrates (sugars)carboxylic acids present in amino acids and other thingsethers present in lipidsamines present in amino acids and other thingsesters present in lipidsphosphates present in DNA, biochemical cofactors, and lipidsphosphate esters present in polynucleotidesdisulfides present in some proteinsB. macromolecules = polymers of organic compounds; typically generated via enzymatic coupling reactions that remove watera. proteins = made of 20 common amino acidsb. polysaccharides = made of monosaccharides (sugars)c. nucleic acids (DNA) = made of nucleotidesd. lipids = mostly made of carbon and hydrogen; associated with membranesCELLS: PROKARYOTIC VS. EUKARYOTICA. prokaryotic cells = a group of organisms that lack a cell nucleus or any other membrane-bound organelles; single-celled organisms, such as bacteriaa. smaller than eukaryotic cells – small size provides a high surface area to volume ratiob. less obvious internal organization – most have no internal membrane compartmentsc. lack a nucleus – DNA is packed in a region of the cytoplasm called the nucleoidd. usually enclosed by an outer cell wall and a periplasmic membrane, which separates the outer cell wall from the cell membranee. chromosomes usually contain a relatively small number of genes, but theycarry out most of the fundamental biological reactions found in all cellsf. the genes of many prokaryotic cells have been sequenced, which has helped scientists determine which genes are responsible for the biological reactions that are essential to lifeg. diffusion = an adequate mechanism for the distribution of nutrients in the prokaryotic cytoplasmB. eukaryotic cells = a group of organisms whose cells contain complex structures enclosed within membranes; includes plants, animals, fungi, and protistsa. the defining membrane-bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleusb. larger than prokaryotic cells (most are 1000x greater in volume)c. contain 2 types of partitioning within the cell:i. cytoskeleton = fibers connected by movement; provides the cell with structure and support– the diffusion of large molecules, such as enzymes, is greatly slowed by the presence of the cytoskeletonii. membrane-enclosed organelles:nucleus genetic informationmitochondria & chloroplasts chemical energy productionlysosomesperoxisomes housekeepingvacuolesendoplasmic reticulum protein synthesisGolgi apparatus addresses traffickingWATERA. water is an excellent solvent for biological systems because of its:a. viscosity – water does not impede the movement of dissolved moleculesb. size – water molecules are small, relative to the molecules of other solventsc. specific heat – water has a high specific heat, which makes water resistantto temperature changes; results in water having a high heat of vaporizationd. polarity – water is polar, which means water is capable of making H-bonds… this causes water to be cohesive and have a high surface tensione. also, all cells consist of mostly water (65 – 90%)B. water has a high melting point and a high boiling pointC. water can solvate highly polar compounds, such as salts… if water has solvated (dissolved) a compound, then that compound is said to be hydratedD. solvation vs. hydration:a. polar substances are “solvated”b. ionic substances are “hydrated” – solvated much more heavilyE. because of its polarity, water can weaken electrostatic forces between moleculesF. cellular diffusion – the diffusion of solutes in the cytoplasm is different than in a pure solvent because:a. the viscosity of the cytoplasm is higher than in pure waterb. charged solutes will bind to other compounds transiently in the cytoplasm,retarding diffusionc. solutes will collide with other solutes in the cytoplasmG. osmotic pressure = the pressure which needs to be applied to a solution to prevent the inward flow of water across a semipermeable membrane; the phenomenon arises from the tendency of a pure solvent to move through a semipermeable membrane into a solution containing a solute, to which the membrane is impermeablea. the molecules of a cell possessing a semipermeable membrane (with differing concentrations of solute on both sides of the membrane) will diffuse across the membrane… the pressure required to prevent solvent from diffusing across a membrane is called the osmotic pressureb. osmotic pressure depends on the total molar concentration of the solute, not on the chemical nature of the solutec. different types of solutions:BONDINGA. ionic bonds = formed between 2 atoms where one atom gives up an electron to another atom; each atom making the bond retains a local charge; not typically the strongest type of bond that 2 atoms can make (when the bond is not placed in solution)B. covalent bonds = formed between 2 atoms where electrons are shared between the 2 atoms; electrons are not always equally shareda. polar covalent bonds = covalent bonds in which electrons are not equally sharedb. polarity = arises when there is a displacement of charge between 2 atoms… this displacement gives rise to what is known as a dipole moment(the displacement of charge between 2 atoms participating in a covalent bond and having a large difference in their electronegativities)C. non-covalent intermolecular forces = the forces responsible for the structure of most biomacromolecules (e.g., DNA and proteins)… there are 4 major non-covalent intermolecular forces:a. electrostatic (charge-charge) interactions = potentially the strongest non-covalent interaction; involves the attraction between 2 oppositely charged atoms; linear forces (orientation of the charged groups does not matter); can be experienced over large distancesthe energy associated with electrostatic interactions is 1 – 200 kJ/moldielectric constant = a measure of how easy it is to cause a shift in electronsHIGH dielectric constants suggest that shifting electrons through a medium requires LESS forceLOW dielectric constants suggest that shifting electrons through a