Allosteric regulation Correct Answers Regulation of a protein's
activity by binding of a molecule at a site other than the active
site that induces a conformational change altering function.
Allosteric site Correct Answers A specific location on an
enzyme distinct from the active site where effectors bind to
modulate enzyme activity.
Amyloid Correct Answers A fibrous aggregate formed by
misfolded proteins adopting β-sheet-rich structures, often
associated with disease.
cDNA Correct Answers Complementary DNA synthesized
from mRNA using reverse transcriptase; represents expressed
genes.
Chaperone Correct Answers A protein that assists other proteins
in folding correctly and prevents aggregation or misfolding.
Chromatin Correct Answers The complex of DNA and histone
proteins that forms chromosomes within the nucleus.
Cooperative binding Correct Answers The phenomenon where
binding of one ligand affects the affinity of remaining sites,
producing a sigmoidal response curve.
Define primary structure. Correct Answers The linear sequence
of amino acids in a polypeptide chain.
, Define protein domains. Correct Answers Independently folded,
functional modules within a polypeptide.
Define secondary structure and give examples. Correct Answers
Local folding stabilized by H-bonds between backbone atoms;
examples: α-helix, β-sheet.
Define tertiary structure. Correct Answers The overall 3D
folding of a single polypeptide; stabilized by noncovalent forces
and sometimes disulfide bonds.
Disulfide bond Correct Answers A covalent link between two
cysteine residues (S-S) that stabilizes protein tertiary or
quaternary structure.
Exonuclease Correct Answers An enzyme that removes
nucleotides one at a time from the ends of a DNA or RNA
strand.
Feedback inhibition Correct Answers A regulatory mechanism
in which the end product of a pathway inhibits an enzyme earlier
in that same pathway.
Helicase Correct Answers An enzyme that unwinds the DNA
double helix using ATP hydrolysis.
Histone acetylation Correct Answers The addition of acetyl
groups to lysine residues on histones, reducing positive charge
and loosening chromatin for transcription.