MCQs

Six moles of water are formed from four moles of ammonia. The ratio simplifies to 3:2.

Since one mole contains Avogadro's number of atoms, dividing the molar mass by this constant gives the mass of one atom.

Every mole contains 6.022 × 10²³ particles regardless of the substance.

One mole of propane requires 5 moles of oxygen. Therefore, 2 moles require 10 moles of oxygen.

The balanced equation shows that 1 mole of nitrogen reacts with 3 moles of hydrogen, giving a mole ratio of 1:3.

Digestive enzymes are secreted as inactive zymogens to protect tissues from self-digestion.

Most φ and ψ angle combinations are sterically forbidden for amino acids other than glycine.

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.