DNA replication

• What is the process called when DNA is copied?

  DNA replication
• When does DNA replication take place?

  During interphase
• What are the steps of DNA replication?

  1. Hydrogen bonds break, DNA separates
  2. DNA unwinds
  3. DNA polymerase adds free nucleotides
  4. Formation of two identical DNA molecules
• What enzyme catalyzes the addition of free nucleotides during DNA replication?

  DNA polymerase
• What do the two resulting DNA molecules consist of after replication?

  One new chain and one original chain
• What determines which amino acid a tRNA molecule carries?

  The sequence of bases on the anticodon
• What amino acid does the anticodon CCC carry?

  Glycine
• What codon does the anticodon CCC combine with on the mRNA molecule?

  GGG codon
• What is required for amino acid activation?

  Energy in the form of ATP
• What are the key stages of protein synthesis?

  1. Initiation: Ribosome attaches to start codon
  2. Elongation: Peptide bond forms between amino acids
  3. Termination: Ribosome reaches stop codon and detaches
• What is a polysome system?

  A group of ribosomes on mRNA
• What is produced each time a ribosome moves along an mRNA molecule?

  A polypeptide molecule
• How can a polypeptide be modified after synthesis?

  • Folded
  • Combined with other polypeptides
  • Modified in the Golgi body
• What does the one gene - one polypeptide hypothesis state?

  One gene codes for a single polypeptide
• How many genes are needed to code for the quaternary protein haemoglobin?

  Four genes
• How many alpha helices does collagen have?

  Three identical alpha helices
• How many genes are sufficient to code for collagen?

  One gene