DNA and protein synthesis

• What is the genome


  The complete set of genetic information contained in the cells of an organism
• What is the proteome


  The complete set of proteins that can be produced by a cell
• Describe the structure of messenger RNA (mRNA)


  ~A long, single strand

  ~Its base sequence is complementary to the DNA it was transcribed from
• Suggest advantages of using mRNA rather than DNA for translation

  ~Shorter and contains uracil = breaks down quickly so no excess polypeptide forms

  ~Single stranded and linear = ribosome moves along strand and tRNA binds to exposed bases

  ~Contains no introns
• Describe the structure of transfer RNA (tRNA)


  ~A single strand of around 80 nucleotides that is folded over into a leaf shape

  ~On one end is an anti-codon, on the opposite end is an amino acid binding site
• What is produced by transcription

  mRNA
• Where does transcription take place

  In the nucleus
• Outline the process of transcription

  ~DNA uncoils into two strands with exposed bases. One used as a template

  ~Free nucleotides line up next to their complementary bases, and are joined together by RNA polymerase
• What happens to mRNA after transcription

  ~in eukaryotic cells, pre-mRNA must be spliced to remove introns, leaving only the coding regions

  ~Then it moves out of the nucleus and attaches to a ribosome
• What is produced by translation 


  Proteins
• Where does translation take place


  In the cytoplasm on ribosomes
• Outline the process of translation

  ~The anti codon of tRNA attaches to complementary bases on the mRNA

  ~Amino acids bonded to tRNA form peptide binds, continuing to form a polypeptide chain until a stop codon is reached

  ~This process requires ATP