Translation (L.20)

What is translation?

The process of using the information in mRNA to synthesize a protein.

What is a codon?

A sequence of three mRNA nucleotides that codes for a particular amino acid or signals translation termination.

How many different codons exist?

64 total codons.

How many sense codons are there, and what do they encode?

61 sense codons that encode the 20 amino acids.

What is the start codon?

AUG, which signals the beginning of translation and codes for methionine.

What are the three stop codons?

UAA, UAG, and UGA. They signal the end of translation.

What is the genetic code?

The system by which nucleotide sequences in nucleic acids are translated into amino acid sequences. It is conserved across all life forms.

How are codons read during translation?

mRNA codons are read sequentially, three nucleotides at a time.

What is the function of tRNA during translation?

Transports the appropriate amino acid to the ribosome and uses its anticodon to pair with the complementary mRNA codon.

What is an anticodon?

A sequence of three nucleotides on tRNA that base-pairs with a complementary codon on mRNA.

What type of bond joins amino acids during translation?

Peptide bonds.

What are the two bacterial ribosomal subunits?

The 30S small subunit and the 50S large subunit.

What are the four components assembled during bacterial translation initiation?

The 30S ribosomal subunit, 50S ribosomal subunit, initiator tRNA, and mRNA.

What is the Translation Initiation Region (TIR)?

A dedicated sequence on mRNA where translation begins. It consists of the Shine-Dalgarno site and AUG start codon.

What is the Shine-Dalgarno site?

A sequence on bacterial mRNA that helps position the ribosome for translation initiation.

What happens during translation elongation?

The ribosome moves sequentially along mRNA, and appropriate amino acids are delivered by tRNA based on codon-anticodon pairing. Amino acids are joined by peptide bonds to lengthen the protein.

What is the role of EF-Tu during translation?

Delivers the appropriate aminoacyl-tRNA (amino acid-loaded tRNA) to the ribosome.

What is the role of EF-G during translation?

Translocates tRNA further through the ribosome as the ribosome moves to the next codon.

What happens during translation termination?

Translation ends when a stop codon enters the ribosome's A site, signaling termination and release of the newly made protein.

Why can transcription and translation occur simultaneously in bacteria?

Bacteria lack a nucleus, so transcription occurs in the cytoplasm and ribosomes can begin translating newly made mRNA before transcription is complete.