gene expression

• mRNA


  Carries a complimentary copy of the DNA code from the nucleus to the ribosome
• Codon


  Each triplet of bases on mRNA is known as a codon and codes for 1 specific amino acid
• Amino acids are the subunits that make up a protein
• tRNA


  Folds due to complementary base pairing and has a triplet of bases exposed known as an anticodon
• Anticodon


  The triplet of bases exposed on tRNA that complementary base pairs with a codon on mRNA
• Amino acid attachment site

  The other end of the tRNA molecule where the specific amino acid is attached
• rRNA


  Together with proteins, forms the ribosome
• Translation


  1. Starts at a START codon and ends at a STOP codon

  2. The ribosome exposes one codon on the mRNA allowing tRNA to bring a specific amino acid

  3. The correct anticodon on the tRNA complementary base pairs with the codon

  4. Amino acids are joined by peptide bonds as the polypeptide is formed
• Translation ensures the entire polypeptide chain is produced without any amino acids missing
• Transcription and translation involves three types of RNA: mRNA, tRNA and rRNA
• RNA splicing forms a mature mRNA transcript by removing introns and joining the exons
• tRNA is involved in the translation of mRNA into a polypeptide at a ribosome
• RNA splicing involves removal or introns and spicing together of exons what molecule is produced in this process Mature mRna transcript
• Protein synthesis occurs at ribosomes, where tRNAs bring specific amino acids to the growing polypeptide chain based on their anticodon sequences.
• polypeptide chains fold to form a three dimensional shape which bond holds this three dimensional shape in place

  hydrogen bonds
• which rna molecule combines with proteins to form ribosomes

  rrna
• alternative splicing


  different mature mrna transcripts produced from one primary transcript
• three bases on trna molecule

  anticodon
• three bases on an mrna molecule

  codon
• enables different proteins to be expressed from one gene

  alternative splicing
• where does translation take place

  ribosome
• dna probes are short fragments of dna that


  are used to detect specific sequences in samples of dna