MCB 2000 Exam Questions With 100% Correct Answers

MCB 2000 Exam Questions With 100% Correct Answers Brownian motion - answerthe movement of molecules powered by random fluctuations of environmental energy Brownian motion of what molecule initiates many biochemical interactions? - answerwater Is water polar or non polar? - answerpolar Polarity enables what type of. bonding between H2O molecules? - answerhydrogen bonding Polarity of water accounts for what? - answerthe cohesiveness of water and its ability to dissolve many biochemicals. Hydrophobic effect - answerInability of water to dissolve nonpolar molecules Electrostatic interactions are between? - answerelectrical charges What is another name for electrostatic interactions? - answerionic bonds salt bridges Are ionic bonds weaker or stronger than covalent bonds? - answerstronger The energy of an electrostatic interaction between two charges is given by what? - answerCoulomb's law Coulomb's Law - answerE=K q₁*q₂/Dr What is the dielectric constant in a vacuum? - answer1 What is the dielectric constant in water? - answer80 When do hydrogen bonds occur? - answerwhenever hydrogen is covalently bonded to an electronegative atom How does water disrupt hydrogen bonds between two molecules? - answerby competing for the hydrogen-bonding capability Nonpolar and uncharged molecules can interact electrostatically with - answervan der Waals interactions Basis of van der Waals interaction - answertransient asymmetry in the electron distribution of one molecule will induce complementary asymmetry in a nearby molecule Hydrogen bonds contribute to the stability of what? - answerthe DNA double helix Hydrogen bonds can be broken down by what? - answerthe enzymes of DNA metabolism What type of molecules cluster in aqueous solutions? - answerhydrophobic molecules What is the term for clustering of hydrophobic molecules in aqueous solutions? - answerHydrophobic effect The hydrophobic effect is powered by - answerthe increase in the entropy of water that results when hydrophobic molecules come together Phospholipids have what properties? - answerhydrophobic and hydrophillic amphipathic - answerhaving both a hydrophilic region and a hydrophobic region amphilic - answerboth hydrophilic and hydrophobic What do phospholipids form when exposed to water? - answermembranes The hydrophobic effect powers what? - answerprotein folding Functional groups - answerarrays of atoms that have distinctive chemical properties Phospholipids are - answeramphipathic Amino acids have - answerside chains of differing hydrophobicity pH - answerthe measure of H+ concentration of a solution pH of any solution is defined as - answerpH=log10(1/[H+])= -log10[H+] pKw = - answerpH + pOH = 14 Acids ionize to form - answera proton and a base Conjugate base - answerThe chemical formed upon ionization of an acid Conjugate acid - answerthe acid formed when a base binds a proton The ionization equilibrium of a weak acid is given by - answer The equilibrium constant for this reaction is - answerKa = [H+][A-]/{HA] The larger the Ka - answerthe smaller the pKa, the stronger the acid pH = - answerpKa + log [A-]/[HA]