lecture 5

Question 1

valine has what side group as a side chain?

Answer 1

isopropyl

Question 2

leucine has what as a side chain?

Answer 2

isobutyl

Question 3

isoleucine has what as a side chain?

Answer 3

isobutyl

Question 4

which amino acid has the largest side chain?

Answer 4

tryptophan

Question 5

what is responsible for 280nm absorbance?

Answer 5

trytophan

Question 6

which 2 amino acid has amphiphatic character?

Answer 6

tyrosine, threonine

Question 7

what properties do trytophan have?

Answer 7

fluorescent

Question 8

what measure absorbance? and which amino acid has highest?

Answer 8

beers law trytophan

Question 9

which amino acids are sites of post translational activity?

Answer 9

threonine and serine

Question 10

which amino acids so 0 glycosylation occur?

Answer 10

threonine and serine

Question 11

what type of bond does cyteine form with cysteine?

Answer 11

covalent bond

Question 12

what is most reactive group in proteins?

Answer 12

sulfhydryl

Question 13

which amino acid has nucleophilic activity?

Answer 13

cysteine

Question 14

cysteine must be what for effective anaylsis? it also reacts with what?

Answer 14

alkylated. metal ions

Question 15

what is precursor to antioxidant glutathione?

Answer 15

cysteine

Question 16

which aa can participate in acid/base reactions?

Answer 16

histidine

Question 17

which amino acid has guanino group? and what does it do?

Answer 17

arginine, can interrupt protein structure

Question 18

aa for deamidation reactions (protein ageing)

Answer 18

glutamine

Question 19

esterification reaction possible in which aa?

Answer 19

glutamate and aspartate

Question 20

which aa has cyclic imino acid?

Answer 20

proline

Question 21

amide bond resonance allows for what in the peptide bond?

Answer 21

stability and planar character

Question 22

which bonds in the peptide bond can rotate?

Answer 22

phi and psi

Question 23

phi is what?

Answer 23

in between N and alpha carbon

Question 24

psi is what

Answer 24

in between alpha carbon and carbon

Question 25

when it comes to forming peptide bond, equilibrium favors what? and kinetics are stable for how many years?

Answer 25

hydrolysis instead of synthesis. 1000

Question 26

what does phi bond prefer to be?

Answer 26

-120

Question 27

in alpha helices, how many residues separate h bonding atoms between N and C=O? residues rise at ____A and rotate ____. pitch is ____A

Answer 27

3.6, 1.5, 100 degrees, 5.4

Question 28

describe feeling of alpha and examples

Answer 28

stiff and rigid. fibrin (blood clots), keratin (hair), cytoskeleton, porcupine quills, tropomyosin (muscle)

Question 29

ferritin is what type of helice?

Answer 29

alpha

Question 30

which beta sheet is more stable and why?

Answer 30

antiparallel because of shorter hydrogen bonds between the nitrogen and C=O.

Question 31

when forming a loop what do you find?

Answer 31

glycine, proline and alanine.

Question 32

barrels are used usually for what?

Answer 32

nuclear pore complexes, allowing ions to pass through

Question 33

hairpin turn is what kind of sheer?

Answer 33

beta

Question 34

are omega loops common?

Answer 34

no

Question 35

which amino acids are no favored for alpha helices?

Answer 35

valine, isloleucine, threonine. serine, aspartic acid, asparagine

Question 36

explaine role proline plays in sheets?

Answer 36

disrupts alpha and beta sheets, so it is found in the turns usually in a cis formation

Question 37

urea does what to proteins?

Answer 37

denatures them by disrupting the water bonds.

Question 38

explain difference between simple dimer and hetero tetramer

Answer 38

dimer is quaternary structure with dimer of identical subunites. hetero tetramer is composed of different chains

Question 39

structural plasticity allows for what in hemoglobin?

Answer 39

cooperative oxygen binding

Question 40

what is a newtonian fluid?

Answer 40

viscosity is constant, even when flowing. when one pushes, viscosity does not change. examples are water, milk, vegetable oils, fruit juices, sugar, and salt solutions

Question 41

explain non newtonian fluid

Answer 41

viscosity changes when applied force changes. shear thinning- viscosity decreases when force is applied to the fluid. examples- latex paint, molasses, ketchup and saliva

Question 42

what is the Ph of saliva?

Answer 42

7.4

Question 43

what allows saliva to act as a lubricative film?

Answer 43

glycoproteins