Genetic Code and Translation

These flashcards cover key terms and concepts related to the genetic code and the process of translation.

Codon

A three-nitrogenous base sequence of DNA that codes for an amino acid.

Start codon

The codon AUG, which codes for methionine and indicates the start of translation.

Stop codons

UAA, UAG, and UGA, which do not code for any amino acids.

Reading frame

A linear sequence of codons in a nucleic acid defined by a start codon and ending with a stop codon.

Unambiguous

Characteristic of the genetic code where each of the 61 triplets code for only one of the 20 amino acids.

Degenerate

Most amino acids are encoded by more than one codon.

Universal

Most living organisms use the same genetic code, with some exceptions.

Commaless

There are no breaks between the codons in a reading frame.

Non-overlapping

Triplets in a reading frame are in a tandem sequence and do not overlap.

Substitution mutation

Occurs when a base is replaced with a different base in DNA, resulting in a permanent single-codon change.

Silent mutation

The new codon codes for the same amino acid as the original codon.

Missense mutation

The new codon codes for a different amino acid.

Nonsense mutation

The new codon is a stop codon, resulting in a shorter polypeptide.

Frameshift mutation

Results from the insertion or deletion of bases, altering the reading frame.

mRNA

Messenger RNA that carries genetic information from DNA for translation.

tRNA

Transfer RNA that carries amino acids to the ribosome during translation.

Wobble hypothesis

The third position of the codon and the first position of the anticodon can pair in a relaxed manner.

Aminoacyl tRNA

tRNA molecule that is charged with its corresponding amino acid.

Ribosome

Large particle of rRNA and proteins where translation occurs.

Initiation factors

Proteins required to facilitate the initiation of translation.

Elongation factors

Proteins that assist in the elongation phase of translation.

Termination of translation

Occurs when a stop codon reaches the A site of the ribosome, leading to the release of the polypeptide chain.