structures of protein

Question 1

the side chain of which amino acids can form hydrogen bonds with asparagine

Answer 1

tyrosine

Question 2

what is the particular sequence of amino acids of a protein that are joined together by peptide bond called

Answer 2

the primary structure of a protein

Question 3

strongest type of interaction between side chains of an isoleucine amino acid and a phenylalanine amino acids in a protein

Answer 3

london dispersion forces

Question 4

strongest type of interaction between 2 cysteine amino acid side chains in a protein

Answer 4

disulfide bond

Question 5

what type of intramolecular forces exist between the side chains of glutamic acid and lysine

Answer 5

electrostatic attraction

Question 6

unique structural feature of collagen

Answer 6

triple helix

Question 7

what is the organic part of heme group called

Answer 7

protoporphyrin IX

Question 8

true or false:
heme group affects conformation of the polypeptide

Answer 8

true

Question 9

true or false:
gobular proteins are coiled into compact shapes with hydrophilic outer surfaces that make them water soluble

Answer 9

true

Question 10

true or false:
the a-carbon and the B-pleated sheet are examples of the tertiary structure of a protein

Answer 10

false - secondary

Question 11

quaternary structure of proteins

Answer 11

more than 1 polypeptide chain

that chain interact with one another noncovalently
each chain is called subunit

Question 12

tertiary structure of proteins

Answer 12

noncovalent interactions
backbone H bonding bbtwn polar side chain of aa
hydrophobic interaction btwn nonpolar sidechain
opp charged parts attract e/o
metal ion complexing (iron/zinc)
as central point to organize multiple parts of protein
disulfide bonds – stronger connections btwn aa (cysteines) that can link distant parts of proteins

Question 13

difference between fibrous and gobular

Answer 13

fibrous
- long and strike like
- not soluble in water
- provide structure n support

gobular
- compact balls
- soluble in water
-functions in cells

Question 14

it is the first chaperone protein to be discovered

Answer 14

hsp70

*exist in organisms from prokaryotes to humans

Question 15

it aids in the correct and timely folding of many proteins

Answer 15

protein-folding chaperones

Question 16

these are major factors in protein folding

Answer 16

hydrophobic interactions

Question 17

why do folding occur

Answer 17

inside n away from water - non polar hydrophobic side chain
outside n have access to aq enviro - polar side chain

Question 18

spherical aggregated of lipids arranged so that the polar side head groups are in contact with the water and the non polar tails are sequestered from water

Answer 18

liposomes

Question 19

unraveling of the 3D of a macromolecule caused by the breakdown of noncovalent interactions

Answer 19

denaturation

Question 20

denaturation is caused by

Answer 20

heat
large change in pH
detergents (sodium dodecyl sulfate)
urea and guanidine hydrochloride
B-mercaptoethanol

Question 21

difference between myoglobin and hemoglobin

Answer 21

myoglobin:
stores O2\
bind strongly to O2 at very low pressure
50% at 1 torr partial pressure if O2

hemoglobin:
transport O2
bind strongly to O2 n release easily
100% when O2 pressure is 100 torr

Question 22

one molecule of myoglobin binds -
hemoglobin can binds up to -

Answer 22

one O2
4 molecules of O2

*binding to hemoglobin = positive cooperativity

Question 23

tetramer

Answer 23

2 alpha chains (141 residues long)
2 B chains (146 residues long)

a2B2

*myoglobin are homologous

Question 24

molecules that are made up of smaller subunits (example)

Answer 24

oligomers (dimers, trimers, tetramers)

Question 25

property of multisubunit proteins such that a conformational change in one subunit induces a drastic change in another subunit

Answer 25

allosteric - if 1 changes, all the other subunit will change too

Question 26

pertains to protein that consists of more than one polypeptide chains

Answer 26

quaternary

Question 27

arrangement of subunits with respect to one another

Answer 27

quaternary

Question 28

3D arrangement of all atoms in a protein, including those in side chain and in prosthetic groups

Answer 28

tertiary structure

Question 29

ordered 3D arrangements in space of the backbone atoms in a polypeptide chain

Answer 29

secondary

Question 30

order in which amino acids are covalently linked tgt

Answer 30

primary

Question 31

iron-containing cyclic compound

Answer 31

heme * more than one molecule can bind to heme

Question 32

it consists of a single polypeptide chain of ____ amino acids and a prosthetic group, ____

Answer 32

myoglobin 153 aa heme

Question 33

heme compact structure

Answer 33

a-helical: 8 - stabilized by H bonding B-pleated sheets: absent exterior: polar side chains interior: non polar side chains and 2 histidine

Question 34

heme group

Answer 34

consists of metal ion, Fe (II) 6 coordination site forms 6 metal ion complexation bonds - 4: N atoms of the 4 pyrrole type of porphyrin -5th: N atoms of the imidazole of histidine - 6th: O2

Question 35

protein structure

Answer 35

pri structure (peptide bonds) sec (H bonding backbone) tertiary (polypeptide chains) quaternary (subunits)

Question 36

gobular protein

Answer 36

non polar - inside polar - outside have a-helix and B-sheets soluble in H2O and salt soln have compact structures, spherical

Question 37

contain polypeptide chains organized approx. parallel along a single axis

Answer 37

fibrous protein *long fibers, strong, insoluble in water and able to dilute to salt soln

Question 38

all three individual collagen chains are helices that differ from the a-helix

Answer 38

collagen triple helix (tropocollagen) * held tgt by H bond involving hydroxyproline n hydroxylysine

Question 39

collagen triple helix

Answer 39

organized in water-insoluble fibers of great strength repeating sequence of 3 amino acids

Question 40

repetitive super secondary structures

Answer 40

motifs

Question 41

common nonrepetitive irregular secondary motif in antiparallel B-sheets

Answer 41

B-bulge

Question 42

hydrogen bonds btwn peptide chains can be interchain or intrachain

Answer 42

B-pleated sheets - give rise to zigzag structure n perpendicular to the direction - polypeptide chain lie adjacent to one another (same direction - parallel opp direction - antiparallel) R groups alternate abv and below plane

Question 43

stabilized by H bonds parallel to the helix axis within the backbone of a single polypeptide chain

Answer 43

a-Helix - helical conformation allows linear arrangement = provide max. bond strength and make conformation stable

Question 44

true or false: changes in one amino acid residue in a sequence can alter biological functions

Answer 44

true

Question 45

biologically active protein are polymers that consist of amino acids liked by what type f bonds

Answer 45

covalent peptide bonds

Question 46

true or false: in the absence of bisphosphoglyceate, oxygen binding capacity of Hb wld be lower

Answer 46

false - higher *BPG supply O2 to the growing fetus