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Stack #23559
Question | Answer |
---|---|
What is an Amino acid | compound that contains an amino group and carboxylic group |
protein/polypeptide | polymer of amino acids |
Amino acids to protien / polypeptide | condensation, peptide bond |
Exergonic | G negative, spontaneous |
Endergonic | G positive, nonspontaneous |
How can non - spontaneous rxn still occur | Cells couple nonfavorable metabolic processes to favorable ones so that the net change in free energy is negative |
Why is water molecule polar | uneven distribution of charge, O neg, H positive |
How many hydrogen bonds can water form | Can form 4, since it has 2 hydrogen atoms to donate to H-bond, and 2 pairs of electrons to accept |
Relative strengths of bonds in biomolecules | covalent>ionic>hydrogen>vanderwalls |
Vander walls interaction between 2 polar molecules | dipole -- dipole interaction |
Vander walls interaction b/ween 2 nonpolar molecules | london dispersion forces |
hydrophobic | water fearing, compound that lacks polar groups and is insoluble |
What happens to entropy when hydrophobic molecule is dissolved | Entropy decrease, because water molecule not free to form H bonding |
How can hydrphobic molecules increase entropy | aggregate |
Hydrophobic effect | Water molecules repelled from nonpolar molecule form shell |
amphipathic | molecule w/ both polar and non-polar regions |
What happens when amphipathic molecules are added to water | polar molecules orient themselve toward water, and nonpolar aggregates due to hydrophobic effect |
What are the concentration of H and OH in pure water | 1 x 10 ^ -7 M |
What is the relationsip b/ween Ka and pKa | larger Ka, or lower pKa = stronger acids |
Buffer | system of weak acids and its conjugate base, resist changes in pH |
What happens at midpoint of titration | pH = pKa and [acid] = [conj.base] |
how do you make a good buffer | pH needs to be w/in 1pH unit of pKa |
physiological pH of human body | 6.9 - 7.4 |
Enzyme for H2CO3 buffer | carbonic anhydrase |
Why are ATP bonds called high energy bonds | cleavage of the bond has a large negative free energy |
Why cleavage of ATP bonds release eneryg | ATP hydrolisis products are more stable |
the joining of Ala - Tyr is a | amide bond |
under normal physiological conditions the N term of plypeptide chain looks like what | NH3+ |
whe pH > pKa what form is dominate | conj base, NH2 COO- |
When pH < pKa what form is dominate | Acid, NH3+, COOH |