structures of protein Flashcards

1
Q

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

A

tyrosine

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2
Q

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

A

the primary structure of a protein

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3
Q

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

A

london dispersion forces

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4
Q

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

A

disulfide bond

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5
Q

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

A

electrostatic attraction

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6
Q

unique structural feature of collagen

A

triple helix

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7
Q

what is the organic part of heme group called

A

protoporphyrin IX

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8
Q

true or false:
heme group affects conformation of the polypeptide

A

true

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9
Q

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

A

true

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10
Q

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

A

false - secondary

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11
Q

quaternary structure of proteins

A

more than 1 polypeptide chain

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

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12
Q

tertiary structure of proteins

A

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

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13
Q

difference between fibrous and gobular

A

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

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

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14
Q

it is the first chaperone protein to be discovered

A

hsp70

*exist in organisms from prokaryotes to humans

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15
Q

it aids in the correct and timely folding of many proteins

A

protein-folding chaperones

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16
Q

these are major factors in protein folding

A

hydrophobic interactions

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17
Q

why do folding occur

A

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

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18
Q

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

A

liposomes

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19
Q

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

A

denaturation

20
Q

denaturation is caused by

A

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

21
Q

difference between myoglobin and hemoglobin

A

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

22
Q

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

A

one O2
4 molecules of O2

*binding to hemoglobin = positive cooperativity

23
Q

tetramer

A

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

a2B2

*myoglobin are homologous

24
Q

molecules that are made up of smaller subunits (example)

A

oligomers (dimers, trimers, tetramers)

25
Q

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

A

allosteric

  • if 1 changes, all the other subunit will change too
26
Q

pertains to protein that consists of more than one polypeptide chains

A

quaternary

27
Q

arrangement of subunits with respect to one another

A

quaternary

28
Q

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

A

tertiary structure

29
Q

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

A

secondary

30
Q

order in which amino acids are covalently linked tgt

A

primary

31
Q

iron-containing cyclic compound

A

heme
* more than one molecule can bind to heme

32
Q

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

A

myoglobin
153 aa
heme

33
Q

heme compact structure

A

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

34
Q

heme group

A

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

35
Q

protein structure

A

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

36
Q

gobular protein

A

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

37
Q

contain polypeptide chains organized approx. parallel along a single axis

A

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

38
Q

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

A

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

39
Q

collagen triple helix

A

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

40
Q

repetitive super secondary structures

A

motifs

41
Q

common nonrepetitive irregular secondary motif in antiparallel B-sheets

A

B-bulge

42
Q

hydrogen bonds btwn peptide chains can be interchain or intrachain

A

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

43
Q

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

A

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

44
Q

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

A

true

45
Q

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

A

covalent peptide bonds

46
Q

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

A

false - higher

*BPG supply O2 to the growing fetus