MCQs

Low pH and high CO₂ reduce oxygen affinity, promoting oxygen delivery.

Glycine's small side chain allows conformations inaccessible to other amino acids.

Oxygen binding at one site increases affinity at other sites through conformational change.

β-turns reverse the direction of the polypeptide chain and are stabilized by hydrogen bonding.

Substrate binding induces conformational changes that optimize catalysis.

Myoglobin has a high oxygen affinity and releases oxygen only at low oxygen tension.

pI = (2.34 + 9.60)/2 = 5.97.

Hydroxyproline stabilizes the collagen triple helix through hydrogen bonding.

Tryptophan and tyrosine absorb ultraviolet light strongly near 280 nm.

RNase A spontaneously refolded after denaturation, proving sequence determines structure.

Hydrophobic residues at heptad repeat positions interlock to stabilize the coiled-coil.

Amphipathic helices possess hydrophobic and hydrophilic faces suited for membrane environments.

Domains are independently folded structural units within one polypeptide.

Burying hydrophobic residues releases ordered water molecules, increasing entropy.

The genetic code in DNA determines the amino acid sequence through transcription and translation.

Branched β-carbon side chains create steric hindrance in α-helices.

Binding of oxygen to one subunit increases affinity of the remaining subunits.

These repetitive sequences allow close packing of antiparallel β-sheets.

The φ (phi) and ψ (psi) angles define backbone conformation in proteins.