BIOMG 3300 - Unit 2 Objectives Study Questions
Solved 100% Correct
Why is 280nm the wavelength used to measure protein absorption? - Answer It is where the
max absorbance for W, Y, and F is. These are aromatic AAs, and proteins are the only types of
compounds that would have these molecules. If you see an abs. here, you can be sure that you
have some type of protein
what elutes first in size exclusion chromatography? - Answer larger proteins
posthetic group - Answer the non amino acid part of a conjugated protein
primary structure - Answer AA sequence
secondary structure - Answer regular repeating conformations (alpha helices and b sheets
tertiary structure - Answer 3D structure/folding of a protein
quaternary structure - Answer the arrangment of subunits in a protein (if applicable)
proteins with multiple polypeptides - Answer have multiple subunits and quaternary structure
order of atoms on a polypeptide chain - Answer N-C(alpha)- C(carboxyl)-N-C(alpha)-C(carboxyl)
Why can't peptide bonds rotate? - Answer there is resonance between the C and the N.
A double bond will exist there some of the time, and this prevents rotation
Is the peptide bond polar or nonpolar? - Answer Polar. Stabilized by H bonds in secondary
structure
, Position of H on amino group to O of carbonyl in a peptide bond - Answer trans
Ramachandran plot - Answer shows favorable conformations for peptides. Dark blue=favored,
light blue=unfavored, white=not allwed
2 bonds in polypeptides that have rotation - Answer pi (Calpha-C) and tsi (N-Calpha)
Is there a hole in the middle of the alpha helix? - Answer NO
Alpha helix - Answer a spiral shaped arrangement of a polypeptide chain. Residues stick out
perpendicular to axis
What stabilizes alpha helices? - Answer hydrogen bonds between the H on the N of the peptide
bond, and the carbonyl O on the 4th AA down
Hydrogen bonds in alpha helices are parallel or perpendicular to axis? - Answer parallel
How many AAs are in each turn of the alpha helix? - Answer 3.6
Beta sheets - Answer a structure with plana peptide bonds which can connect different areas of
a polypeptide, or different polypeptides
What stabilizes beta sheets? - Answer H bonds between adjacent chains
antiparallel beta sheet - Answer a beta sheet that includes neighboring regions of a
polypeptide, connected . The direction of amino-carboxyl will be opposite for each chain.
What connects antiparallel beta sheets - Answer beta loops (strand of hydrophilic AAs)
Solved 100% Correct
Why is 280nm the wavelength used to measure protein absorption? - Answer It is where the
max absorbance for W, Y, and F is. These are aromatic AAs, and proteins are the only types of
compounds that would have these molecules. If you see an abs. here, you can be sure that you
have some type of protein
what elutes first in size exclusion chromatography? - Answer larger proteins
posthetic group - Answer the non amino acid part of a conjugated protein
primary structure - Answer AA sequence
secondary structure - Answer regular repeating conformations (alpha helices and b sheets
tertiary structure - Answer 3D structure/folding of a protein
quaternary structure - Answer the arrangment of subunits in a protein (if applicable)
proteins with multiple polypeptides - Answer have multiple subunits and quaternary structure
order of atoms on a polypeptide chain - Answer N-C(alpha)- C(carboxyl)-N-C(alpha)-C(carboxyl)
Why can't peptide bonds rotate? - Answer there is resonance between the C and the N.
A double bond will exist there some of the time, and this prevents rotation
Is the peptide bond polar or nonpolar? - Answer Polar. Stabilized by H bonds in secondary
structure
, Position of H on amino group to O of carbonyl in a peptide bond - Answer trans
Ramachandran plot - Answer shows favorable conformations for peptides. Dark blue=favored,
light blue=unfavored, white=not allwed
2 bonds in polypeptides that have rotation - Answer pi (Calpha-C) and tsi (N-Calpha)
Is there a hole in the middle of the alpha helix? - Answer NO
Alpha helix - Answer a spiral shaped arrangement of a polypeptide chain. Residues stick out
perpendicular to axis
What stabilizes alpha helices? - Answer hydrogen bonds between the H on the N of the peptide
bond, and the carbonyl O on the 4th AA down
Hydrogen bonds in alpha helices are parallel or perpendicular to axis? - Answer parallel
How many AAs are in each turn of the alpha helix? - Answer 3.6
Beta sheets - Answer a structure with plana peptide bonds which can connect different areas of
a polypeptide, or different polypeptides
What stabilizes beta sheets? - Answer H bonds between adjacent chains
antiparallel beta sheet - Answer a beta sheet that includes neighboring regions of a
polypeptide, connected . The direction of amino-carboxyl will be opposite for each chain.
What connects antiparallel beta sheets - Answer beta loops (strand of hydrophilic AAs)
