RNA and protein synthesis

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RNA and protein synthesis
2011-09-21 13:18:12
RNA protein synthesis biology

Higher biology - RNA and protein synthesis
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  1. What does RNA stand for?
    Ribonucleic acid
  2. State three differences between DNA and RNA
    • DNA contains deoxyribose sugar but RNA contains ribose sugar
    • DNA contains a double strand (double helix) but RNA contains a single strand
    • DNA contains thymine but RNA contains uracil
  3. What are the two types of RNA?
    • mRNA - messenger RNA
    • tRNA - transfer RNA
  4. What are the two stages of protein synthesis?
    • Transcription - involving mRNA
    • Translation - involving tRNA
  5. Describe protein synthesis
    • In the nucleus DNA is unzipped by an enzyme
    • One section of one strand of DNA is exposed and a molecule of mRNA is transcribed using free nucleotides present in the nucleus. Complementary base pairing (G-C, C-G, A-U, T-A) determines the sequence of the bases on the mRNA molecule. When the mRNA molecule is complete, it leaves the nucleus through the nuclear pores and enters the cytoplasm
    • In the cytoplasm there are tRNA molecules which bear a triplet (anticodon) of bases corrosponding to a particular amino acid. Each tRNA molecule picks up the appropriate amino acid from the cytoplasm.
    • The mRNA molecule becomes attached to a ribosome. Its triplet code is read and a tRNA anticodon links with each complementary codon of bases on the mRNA molecule.
    • Peptide bonds form between adjacent amino acids.
    • The completed protein is then released into the cytoplasm