Bio

• How many stages in protein synthesis : 2
• Where does each stage of protein synthesis take place?

  1st stage in nucleus

  2nd stage in cytoplasm
• Name of the first stage in protein synthesis?

  • Transcription
  • Base sequence of genes copies into a complementary template molecule
  • Molecule is called mRNA: a single-stranded molecule
  • It passes out of the nucleus into cytoplasm
• Name of the second stage in protein synthesis?

  • Translation
  • mRNA molecules attaches to a ribosome
  • Amino acid are brought to ribosomes on carrier molecules
  • Carrier molecules are called tRNA
  • Ribosome reads triplets of bases on mRNA
  • Uses this to join correct amino acids in the correct order
• What happens when the chain is complete in the 2nd stage?

  Protein chain folds into its unique shape

  Allow it to do its job
• What is a change to a base called?

  Mutation
• What are proteins?

  Polymers of amino acids
• What does the order of amino acid determine?

  Determines the protein's shape and function
• What determines order of amino acid?

  Sequence of bases in the gene for the protein
• How does a cell read a DNA sequence?

  As triplets of bases

  Each triplet encodes for a specific amino acid
• Why does a mutation not change amino acid sequence somtimes?

  Different base triplets can sometimes encode for same amino acid
• What effect can a mutation have?

  Creates a different amino acid - which alters the shape

  Can have a huge effect on its function

  Active site of enzyme can change shape - so the it could lose its strength
• Define non-coding parts of DNA?

  These are found in the chromosome

  These regions switch genes on/off

  Tell genes when to produce proteins