The Genetic Code and Translation

This set of flashcards covers key vocabulary related to the genetic code and the process of translation in protein synthesis.

Genetic Code

The set of rules by which information encoded in genetic material is translated into proteins, consisting of codons that correspond to specific amino acids.

Codon

A sequence of three nucleotides in mRNA that specifies a particular amino acid.

Start Codon

The codon AUG, which signals the beginning of translation and codes for the amino acid methionine.

Stop Codon

Codons such as UAA, UAG, and UGA that signal the end of protein synthesis and do not code for any amino acids.

Reading Frame

The way nucleotides in mRNA are grouped into codons, starting from a specific start codon.

Substitution Mutation

A mutation that involves the replacement of one base in the DNA sequence with a different base, leading to changes in the resulting protein.

Silent Mutation

A type of substitution mutation where the new codon still codes for the same amino acid as the original codon.

Missense Mutation

A substitution mutation that results in a codon coding for a different amino acid, potentially altering protein function.

Nonsense Mutation

A substitution mutation that changes a codon to a stop codon, leading to a prematurely shortened polypeptide.

Insertion Mutation

A mutation that involves the addition of one or more nucleotide bases into a DNA sequence, which can disrupt the reading frame.

Frameshift Mutation

A mutation caused by insertions or deletions that shift the reading frame, altering all downstream codons.

Transfer RNA (tRNA)

Molecule that carries amino acids to the ribosome during translation and has an anticodon that pairs with the corresponding codon in mRNA.

Charging of tRNA

The process of attaching an amino acid to the 3’ end of a tRNA, facilitated by aminoacyl-tRNA synthetases.

Wobble Hypothesis

The theory suggesting that the third base in a codon can be flexible, allowing some tRNAs to pair with more than one codon.

Ribosome

A cellular structure composed of ribosomal RNA and proteins that facilitates the translation of mRNA into a polypeptide.

Initiation of Translation

The first step of translation where mRNA binds to the ribosome and the first tRNA binds to the start codon.

Elongation of Translation

The process during translation where the polypeptide chain is extended by adding one amino acid at a time, as dictated by the mRNA codons.

Termination of Translation

The final step of translation where the ribosome encounters a stop codon, leading to the release of the completed polypeptide.

Polyribosomes

Structures formed when multiple ribosomes simultaneously translate a single mRNA strand.