Final answer:
The correct statement regarding transcription and translation is that the nucleotide sequence in a mRNA codon is an exact match to the DNA triplet that coded for it, but with uracil replacing thymine. This process involves transcription to generate mRNA and translation to synthesize proteins.
Step-by-step explanation:
The correct statement regarding transcription and translation, and the one that most accurately reflects the cellular processes, is option 2: The nucleotide sequence in a mRNA codon is an exact copy of the DNA triplet that coded for it, except that uracil is substituted for thymine. During transcription, the enzyme RNA polymerase builds an mRNA strand by adding nucleotides that are complementary to the DNA template strand. As a result, adenine (A) pairs with uracil (U) in RNA instead of thymine (T) as in DNA, guanine (G) pairs with cytosine (C), and vice versa. Then, during translation, the mRNA sequence is decoded by tRNA molecules which have anticodons complementary to the mRNA codons. These tRNAs bring the appropriate amino acids to the ribosome, where the protein is synthesized according to the sequence specified by the mRNA.