Final answer:
The first three octets of a MAC address represent the OUI. In translation from an mRNA sequence, four codons result in a peptide that is four amino acids long. Nitrogen with an atomic number of seven has two electron shells.
Step-by-step explanation:
The number of octets of a MAC address that represent the Organizationally Unique Identifier (OUI) is three. An OUI is a 24-bit number that uniquely identifies a vendor, manufacturer, or other organization. This means that the first three octets (where each octet is 8 bits) of the MAC address are used for the OUI, specifying the organization that issued the address.
For the peptide translation from the given mRNA sequence (5'-AUGGGCUACCGA-3'), the length of the peptide that would be translated is four amino acids. This is because the sequence contains four codons (AUG, GGC, UAC, CGA), and each codon corresponds to one amino acid, except when a stop codon is present which signals termination of translation. In this case, there is no stop codon within these four codons.
Nitrogen, with an atomic number of seven, most likely has two electron shells. According to the electronic configuration rules, the first two electrons would fill the first shell, and the remaining five would be in the second shell.