Answer:
1
ADNA sequences use the nucleotides A, T, G, and C, while mRNA sequences use the nucleotides A, U, G, and C.
B It was easier to decode the messages written in mRNA sequences because these sequences could be translated directly into the amino acid sequence.
2
A The cellular enzyme that carries out transcription is RNA polymerase.
B The cellular machine that carries out translation is the ribosome, which is composed of both rRNA and ribosomal proteins.
C In a eukaryotic cell, an mRNA transcript often has additional untranslated regions and a poly-A tail. A eukaryotic mRNA transcript would need to be transported from the nucleus to the cytoplasm before it could be translated.
3
A Some amino acids are encoded by several codons. If a single nucleotide mutation still encodes for the same amino acid, the resulting amino acid sequence would not be affected. This happens most often with nucleotides in the third position of a codon.
B If a single nucleotide mutation changes the amino acid encoded, the resulting amino acid sequence would be affected. This happens most often with nucleotides in the first and second positions of a codon.
C Nucleotide insertions and deletions cause frameshift mutations, which change the reading frame of translation and will encode completely different amino acids from that point forward.
4
A There are only 20 canonical amino acids, so the letters B, J, O, U, X, and Z are not used as one-letter codes.
B It was a little difficult to not use the letters B, J, O, U, X, and Z at first, but there are messages to write without these six letters.
Step-by-step explanation: