ACTUAL Exam Questions and CORRECT
Answers
primary protein structure consists of ____ - CORRECT ANSWER - a linear sequence of
amino acids in a chain
(ie. gly-x-y-gly-x-y)
4 main types of secondary protein structure - CORRECT ANSWER - 1. alpha helix
2. beta pleated sheets
3. bends / turns
4. loops
which is more stable: alpha helices or beta sheets?
what stabilizes these secondary strucutres? - CORRECT ANSWER - beta sheets are more
stable (more H-bonds)
H-bonds stabilize these structures
___ are formed between carbonyl oxygen bonds and the amide nitrogen of another peptide 4
residues ahead - CORRECT ANSWER - alpha helices
what is not typically found in alpha helices (ie. what substance) and why? - CORRECT
ANSWER - proline
it kinks the helix
___ are formed when beta-strands are connected laterally by 2-3 hydrogen bonds (ie. 2+ peptide
chains) - CORRECT ANSWER - beta sheets
they're connected by H-bonds between C-O and N-H groups
, beta sheets can be either parallel or antiparallel - CORRECT ANSWER - true
short, non randomized stretches of polypeptide chains that join two secondary structures -
CORRECT ANSWER - bends, turns, loops
stabilized by: H-bonds, salt bridges, hydrophobic reactions
tertiary protein structures are ___ - CORRECT ANSWER - interactions between
secondary structures
examples: motifs, domains
domains: protein section sufficient to perform a task (defined regions w specific functions;
conserved functions across proteins)
motifs: common arrangements of secondary structures to generate a tertiary arrangement
quarternary protein structures are ___ - CORRECT ANSWER - interactions of 2+ tertiary
subunits to form a functional enzyme / unit
what do myoglobin and hemoglobin bind?
and why? - CORRECT ANSWER - bind oxygen
homologous proteins (similar primary sequence and function)
they bind oxygen because oxygen is nonsoluble in many fluids (like blood) so we need an
oxygen transporter
what are tertiary and secondary protein structure stabilized by? (3 things) - CORRECT
ANSWER - hydrophobic interactions
hydrogen bonds