micro 11.4 pt 2

Shine-Dalgarno Sequence

A ribosome-binding site on prokaryotic mRNA that helps position the ribosome at the start codon.

Kozak Sequence

A nucleotide sequence in eukaryotic mRNA that helps the ribosome recognize the start codon.

Initiator tRNA

The specialized tRNA that recognizes the start codon and begins protein synthesis.

Formylmethionine (fMet)

The modified amino acid used to initiate protein synthesis in bacteria.

Methionine (Met)

The first amino acid incorporated into proteins during translation in eukaryotes.

Translation Initiation Complex

The assembled complex of mRNA, ribosomal subunits, initiator tRNA, and initiation factors that begins translation.

Initiation Factors (IFs)

Proteins that assist in assembling the translation initiation complex in prokaryotes.

Elongation Factors (EFs)

Proteins that help deliver tRNAs to the ribosome and promote ribosome movement during elongation.

Release Factors (RFs)

Proteins that recognize stop codons and terminate translation.

Peptidyl Transferase

The catalytic activity of the large ribosomal subunit that forms peptide bonds between amino acids.

Translocation

The movement of the ribosome one codon along the mRNA after peptide bond formation.

Aminoacyl (A) Site

The ribosomal site where an incoming charged tRNA binds.

Peptidyl (P) Site

The ribosomal site that holds the tRNA carrying the growing polypeptide chain.

Exit (E) Site

The ribosomal site where an empty tRNA exits after transferring its amino acid.

Reading Frame

The grouping of nucleotides into consecutive codons during translation.

Open Reading Frame (ORF)

A continuous sequence of codons beginning with a start codon and ending with a stop codon that can encode a protein.

Wobble Hypothesis

The concept that the third base of a codon can pair less specifically with the first base of a tRNA anticodon.

Wobble Base Pairing

Flexible pairing between the third nucleotide of a codon and the first nucleotide of an anticodon.

Isoacceptor tRNA

Different tRNA molecules that carry the same amino acid but recognize different codons.

Chaperone Protein

A protein that assists newly synthesized proteins in folding into their correct three-dimensional structure.

Protein Folding

The process by which a polypeptide acquires its functional three-dimensional shape.

Primary Protein Structure

The linear sequence of amino acids in a polypeptide.

Secondary Protein Structure

Local folding patterns of a protein, such as α-helices and β-pleated sheets.

Tertiary Protein Structure

The overall three-dimensional shape of a single polypeptide.

Quaternary Protein Structure

The arrangement of multiple polypeptide subunits into a functional protein.

Cotranslational Folding

Protein folding that begins while the polypeptide is still being synthesized by the ribosome.

Post-Translational Processing

Chemical modifications made to a protein after translation, such as cleavage, phosphorylation, or glycosylation.

Proteolytic Cleavage

The cutting of a newly synthesized protein into its active form.

Glycosylation

The addition of carbohydrate groups to a protein after translation.

Phosphorylation

The addition of a phosphate group to a protein to regulate its activity or function.