LIVING SYSTEMS A attributes of living systems a reception and response to signals b capable of using an energy source c capable of movement development and replication d are typically evolving via mutations B the flow of information DNA RNA proteins sometimes RNA DNA but proteins NEVER RNA or DNA ORGANIC CHEMISTRY A functional groups alcohols ketones aldehydes carboxylic acids ethers amines esters phosphates phosphate esters disulfides present in carbohydrates sugars present in amino acids and other things present in lipids present in amino acids and other things present in lipids present in DNA biochemical cofactors and lipids present in polynucleotides present in some proteins B macromolecules polymers of organic compounds typically generated via enzymatic coupling reactions that remove water a proteins made of 20 common amino acids b polysaccharides made of monosaccharides sugars c nucleic acids DNA made of nucleotides d lipids mostly made of carbon and hydrogen associated with membranes CELLS PROKARYOTIC VS EUKARYOTIC A prokaryotic cells a group of organisms that lack a cell nucleus or any other membrane bound organelles single celled organisms such as bacteria a smaller than eukaryotic cells small size provides a high surface area to b less obvious internal organization most have no internal membrane c lack a nucleus DNA is packed in a region of the cytoplasm called the volume ratio compartments nucleoid d usually enclosed by an outer cell wall and a periplasmic membrane which separates the outer cell wall from the cell membrane e chromosomes usually contain a relatively small number of genes but they carry out most of the fundamental biological reactions found in all cells f 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 life WATER g diffusion an adequate mechanism for the distribution of nutrients in the prokaryotic cytoplasm B eukaryotic cells a group of organisms whose cells contain complex structures enclosed within membranes includes plants animals fungi and protists a the defining membrane bound structure that sets eukaryotic cells apart from prokaryotic cells is the nucleus b 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 cytoskeleton ii membrane enclosed organelles nucleus mitochondria chloroplasts lysosomes peroxisomes vacuoles endoplasmic reticulum Golgi apparatus genetic information chemical energy production housekeeping protein synthesis addresses trafficking A water is an excellent solvent for biological systems because of its a viscosity water does not impede the movement of dissolved molecules b size water molecules are small relative to the molecules of other solvents c specific heat water has a high specific heat which makes water resistant to temperature changes results in water having a high heat of vaporization d polarity water is polar which means water is capable of making H bonds this causes water to be cohesive and have a high surface tension e also all cells consist of mostly water 65 90 B water has a high melting point and a high boiling point C water can solvate highly polar compounds such as salts if water has solvated dissolved a compound then that compound is said to be hydrated D solvation vs hydration a polar substances are solvated b ionic substances are hydrated solvated much more heavily E because of its polarity water can weaken electrostatic forces between molecules F 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 water b charged solutes will bind to other compounds transiently in the cytoplasm retarding diffusion c solutes will collide with other solutes in the cytoplasm G 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 impermeable a 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 pressure b osmotic pressure depends on the total molar concentration of the solute not on the chemical nature of the solute c different types of solutions BONDING shared A 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 shared a polar covalent bonds covalent bonds in which electrons are not equally b 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 distances i the energy associated with electrostatic interactions is 1 200 kJ mol ii dielectric constant a measure of how easy it is to cause a shift in electrons HIGH dielectric constants suggest that shifting electrons through a medium requires LESS force LOW dielectric constants suggest that shifting electrons through a medium requires MORE force example salt bridges ion pairing the attractive electrostatic forces between 2 ions of opposite charge in a protein that adds to protein structure force q1q2 r2D where D is the dielectric constant