Beginning in the nucleus, the DNA molecule of the eukaryotic cell will be transcribed. The enzyme RNA polymerase separates the two strands of DNA and attaches the complementary nucleotides. The section of DNA being transcribed is the transcription unit. The RNA grows in a 5' to 3' direction. The initiation site for RNA synthesis is bound to by RNA polymerases. The promoter is the initiation site, and nucleotide sequences that RNA polymerase need transcription factors (specific proteins) to recognize. After the enzyme reaches the segment that is a termination signal, it stops adding nucleotides. This primary transcript is then processed to be functional mRNA. The ends are modified to protect, lengthen, and help the strand be recognized. A 5' cap of guanine and a Poly (A) cap (added to the 3' end) of adenine are attached. This messengerRNA now leaves the cell to give the message from the DNA to make polypeptides.

Translation occurs with the transferRNA (tRNA). It goes to the aminoacyl-tRNA synthetase, which joins an amino acid to its specific tRNA. The initiation is where mRNA, the tRNA with the first amino acid, and the two subunits of a ribosome come together. The mRNA molecule is in triplets known as codons. The tRNA matches up complementary triplets of anticodons. Elongation occurs with codon recognition where hydrogen bonds form with the mRNA codon and the tRNA anticodon. Then a peptide bond forms so that the new polypeptide is added to the growing chain. Translocation occurs so that the tRNA goes to the exit site and then leaves. Once the tRNA codes for the terminating (or stop) codon, elongation stops. The chain of amino acids then goes where it needs to (e.g. with others, an organelle, etc.)

A deletion or addition in DNA nucleotides would throw off the reading frame. Wrong triplets will be formed, and the wrong amino acids will be coded for. This would form an incorrect polypeptide chain and mess things up. A substitution in one of the nucleotides might not be as bad. It would only mess up its particular triplet. Even then, wobble may allow the tRNA to still code for the correct amino acid and there wouldn't be a problem.

P.S. Yes, this is all me...