Practical

Question 1

autoionization of water

Answer 1

ability of water to act as bronsted acid or bronsted base

water donating proton to another water molecule

Question 2

bronsted acid

Answer 2

proton donor

Question 3

bronsted base

Answer 3

proton acceptor

Question 4

concentration of H+ in pure water at 25*C

Answer 4

1.0 E-7 M

Question 5

Kw

Answer 5

1.0 E-14

H*OH

Question 6

narrow range pH paper

Answer 6

2 pH units

Question 7

wide range pH paper

Answer 7

12 pH units

Question 8

pH meter

Answer 8

glass electrode connected to meter
voltage produced depends on pH of solution
electrical potential produced is linear function of pH

voltage produced is read by the meter and calibrated to .01pH units

must be standardized with buffer solutions with known pHs

Question 9

titration

Answer 9

measured amounts of base are added to measured amount of acid or vice versa

Question 10

equivalence point

Answer 10

point in titration in which acid is exactly neutralized

moles acid = moles base

Question 11

pH = pKa

Answer 11

inflection point

Question 12

BUFFER PROBLEM 3

Answer 12

learn it

Question 13

first level of p structure

Answer 13

primary structure; linear sequence of AA linked by peptide bonds

Question 14

second level of p structure

Answer 14

sterical arrangement of amino acid residues in specific parts of polypeptide chain

Question 15

secondary structure elements

Answer 15

parallel/antiparallel b sheets
a-helices
b-turns

Question 16

tertiary structure

Answer 16

3D structure of pp chain

Question 17

function of protein is dependent on

Answer 17

correct 3D structure (tert)

Question 18

2 abundant classes of proteins based on tert structure

Answer 18

fibrous

globular

Question 19

fibrous proteins

Answer 19

simple, repeating elements of secondary structure and have structural roles

silk fibroin

Question 20

silk fibroin

Answer 20

layers of antiparallel b-sheets

Question 21

globular prtoeins

Answer 21

several types of secondary structure in same pp chain

myoglobin

Question 22

quaternary structure

Answer 22

protein has 2 or more pp subunits that can interact w each other

hemoglobin

Question 23

protein native state

Answer 23

functional folded conformation

lowest Gibbs free energy

Question 24

native state represents

Answer 24

most thermodynamically stable state

Question 25

proteins conformation is stabilized by

Answer 25

weak molecular interactions (van der waals, H bonding, hydrophobic interactions, ionic interactions)

covalent and noncovalent contribute to native state

Question 26

most stable conformation of protein will have

Answer 26

max weak interactions

easily disrupted; only marginally stable

Question 27

charged or polar AA on

Answer 27

surface of a protein

promote appropriate folding by interacting w water molecules via h bonds

Question 28

h bonds

Answer 28

between atoms on 2 diff side chains

water and AA on surface

carbonyl and amide groups in peptide backbone that give rise to a-helix and b-strand conformations

Question 29

hydrophobic interactions

Answer 29

major driving force for native fold

forms solvation layers

solvation layer is highly ordered; unfavorable decrease in entropy of water

nonpolar AA cluster together, increases entropy because less solvation

Question 30

soluble prtoein

Answer 30

hydrophobic residues in interior

h bonds maximized