RNA: Structures and Functions Biology 9

RNA Base Pairing RNA –> DNA Base Pairing: A ---- U G ---- C 4 Nitrogen Bases in RNA: Adenine Guanine Uracil Cytosine RNA –> DNA Base Pairing: A ---- U G ---- C

RNA vs. DNA 3 major differences Deoxyribose Sugar Ribose Sugar Double Strand Single Strand (generally) Uses Thymine (T) Uses Uracil (U)

Messenger RNA (mRNA) Basic Structure: Basic Function Single Strand of RNA Basic Function Make a copy of DNA instructions to make a protein Takes those instructions from DNA to Ribosome to make a protein Every 3 bases is a Codon Small enough to leave the nucleus. DNA is too big!

mRNA (in orange)

Transfer RNA (tRNA) Basic Structure: Basic Function: Coiled RNA strand Amino Acid attached to the top Anti-codon on the bottom Basic Function: Transfer amino acids to the ribosome to make a protein Anti-codon on tRNA matches/ reads codon on mRNA

tRNA

tRNA: Molecular Model

Codons and AntiCodons Anticodon Codon Polypeptide Codon Anticodon 3 base sequence on mRNA that specify a single amino acid to be added to the polypeptide (protein) Anticodon 3 base sequence on tRNA that are complimentary to the mRNA codon t RNA mRNA Polypeptide Anticodon Codon

The Genetic Code The 64 Codons that code for Amino Acids

Transcription and Translation Animation Video Website: http://207.207.4.198/pub/flash/26/transmenu_s.swf

Transcription Detail Overview: Steps: mRNA Overview: A DNA gene is copied in the form of mRNA Steps: RNA Polymerase separates DNA strands RNA Polymerase moves along one of the DNA strands (template) RNA Polymerase makes mRNA by attaching RNA nucleotides that match the DNA template

Transcription - Translation

Translation Detail Overview: Steps: mRNA copy provides instructions for assembling amino acids into a protein Occurs at the ribosome Steps: mRNA enters the ribosome tRNA molecules bring amino acids to the ribosome tRNA anticodons match with mRNA codons to put amino acids in the right order According to the Genetic Code

Translation