Alpha helices are a type of secondary structure in proteins. What is the length of a 33.0 kDa single‑stranded α‑helical protein segment? Assume a mean residue mass of 110 Da . length: Å

450 Å

Explanation:

The amino acids in an α-helix are arranged in a right-handed helical structure where each amino acid residue corresponds to a 100° turn in the helix, and a translation of 1.5 Å (0.15 nm) along the helical axis

Mass of protein= 33.0 kDa

33.0 kDa ×(1000Da/kDa) × ( 1 residue/ 110 Da)

=33.0 ×1000 × 0.0091

= 300 residues

300 residues × (1.5Å /residue)

=450 Å

the equation that correctly represent the reaction for formation of ammonia is

n2+ 3h2 → 2nh3 (answer d)

1 mole of nitrogen gas (n2) react with 3 moles of hydrogen gas (h2) to form 2 moles of ammonia ( nh3). this is in a process known as haber process were iron is used as a catalyst and reaction take place that a higher temperature and pressure. the process is exothermic hence energy is released.