Molecular Biology Module 7: The Genetic Code

The genetic code is a degenerate triplet code, which means that multiple codons can code for the same amino acid. For example, six different codons can code for the amino acid alanine. This degeneracy is primarily determined and maintained by interactions between amino acids and tRNA.

The ability of the third base of a codon to pair with more than one base in the anticodon of tRNA. This allows for flexibility in codon recognition and contributes to the degeneracy of the genetic code.

A specific sequence of three consecutive nucleotides that codes for a particular amino acid. The genetic code is read in sets of three.

A type of RNA that carries amino acids to the ribosome during protein synthesis. It has an anticodon sequence that pairs with the codon on mRNA, ensuring that the correct amino acid is added to the growing polypeptide chain.

The ability of an organism to translate its genetic information into proteins. This process involves the interactions between mRNA, tRNA, and ribosomes. The code is universal and shared by all living organisms.

A molecule that carries a specific amino acid to the ribosome for protein synthesis, where it binds to the corresponding codon on mRNA.

The region on tRNA that recognizes and binds to a specific codon on mRNA.

The genetic code is degenerate because multiple codons can code for the same amino acid.

The process of deciphering the genetic code and synthesizing proteins based on the mRNA sequence.

A continuous sequence of codons starting with a start codon (AUG) and ending with a stop codon.

Enzymes that attach the correct amino acid to each tRNA molecule.

The ability of some tRNAs to recognize more than one codon, making the genetic code even more degenerate.

The genetic code was deciphered using experiments that identified the specific amino acid encoded by each codon. One pioneering experiment involved using synthetic RNA molecules to create polypeptides.

A codon is a sequence of three nucleotides in mRNA that specifies a particular amino acid. These three-letter 'words' are the language of the genetic code.

The sequence of codons in mRNA determines the order of amino acids in a protein, ultimately defining the protein's structure and function.

tRNA (transfer RNA) acts as a molecular adaptor, recognizing specific codons on mRNA and bringing the corresponding amino acid to the ribosome for protein synthesis.

To participate in protein synthesis, tRNA needs to be attached to its specific amino acid. This process is called aminoacylation.

A stop codon signals the end of protein synthesis. Three codons (UAA, UAG, UGA) do not code for any amino acid and act as 'stops' in the protein-building process.

Each codon in mRNA corresponds to a specific amino acid, allowing the cell to build a protein with the correct sequence. This code is universal across most organisms.

A complex molecular machine composed of two subunits, a large subunit and a small subunit, responsible for protein synthesis.

The subunit of the ribosome where the mRNA binds and decoding takes place. It is responsible for recognizing the start codon and laying the foundation for protein synthesis.

The subunit of the ribosome where the polypeptide chain is assembled. It contains the peptidyl transferase center, where peptide bonds are formed.

A measure of the sedimentation rate of particles in a centrifuge. It is used to describe the size and shape of molecules, including ribosomes.

A conserved sequence found in prokaryotic mRNA that interacts with the 16S rRNA of the 30S ribosomal subunit to identify the start site of protein synthesis. It helps position the ribosome for correct translation initiation.

A conserved sequence found in eukaryotic mRNA that interacts with the small ribosomal subunit (40S) to identify the start site of protein synthesis. Similar to the Shine-Dalgarno sequence in prokaryotes.

A type of tRNA that carries the formylmethionine amino acid to the ribosome during initiation of protein synthesis in prokaryotes.

A complex formed by the binding of initiation factors (IF1, IF2, IF3) and GTP to the 30S ribosomal subunit.

An initiation factor that blocks the A site on the 30S subunit, preventing premature binding of tRNA to the A site.

An initiation factor that tags the initiator tRNA (tRNAi-Met) with GTP and guides it to the ribosome, ensuring accurate initiation.

An initiation factor that prevents premature association of the 30S and 50S ribosomal subunits, stabilizes 30S, and checks for accurate tRNAi-Met binding.

A complex formed by the binding of an aminoacyl-tRNA, EF-Tu, and GTP.

An elongation factor that mediates the entry of aminoacyl-tRNAs into the ribosome A site.

An elongation factor that mediates the translocation of the ribosome along the mRNA, moving the peptidyl-tRNA from the A site to the P site.

A site on the ribosome where incoming aminoacyl-tRNAs bind during protein synthesis.

A site on the ribosome where the peptidyl-tRNA (tRNA carrying the growing polypeptide chain) is located.

A special protein factor that recognizes stop codons on mRNA and triggers the release of the polypeptide chain from the ribosome.