genetic code

• what is the definition of the genetic code?

  The rules by which triplets in a DNA base sequence code for the sequence of amino acids in a polypeptide chain.

  • The genetic code is degenerate, universal and non-overlapping
• What does the genetic code consist of ?

  triplets of bases
• What is a codon?


  a sequence of 3 bases on mRNA that codes for a specific amino acid
• What does each triplet of bases code for?

  a particular amino acid
• How are the amino acids joined together and what do they form?

  by PEPTIDE BONDS and they form a POLYPEPTIDE CHAIN
• What is the location of a gene called?


  the locus
• what's the definition for a gene?

  : A length of DNA on a chromosome that codes for the production of one or more polypeptide chains and functional RNA.
• Does all the genome code for proteins?

  NO - non-coding sections of DNA = introns
• what are the non-coding sections of DNA called?

  introns
• what are the coding regions of DNA called?

  exons
• How many nucleotide bases are there?

  4
• there are 4 nucleotide bases which code for 20 different amino acids
• How many amino acids do the 4 nucleotide bases code for?

  20
• What were scientists able to conclude?

  That each amino acid is coded for by one or more combination of triplets.

  Therefore there are 64 possible triplets (4 cubed) meaning that each amino acid is represented by more than one triplet
• how many possible triplets are there?

  64
• what are the types of mutation?

  deletion, substitution , insertion
• give an example of a harmful mutation?

  for example the mutation which leads to the production of sticky mucus and causes CYSTIC FIBROSIS
• what can a change in the base sequence of DNA cause?


  a change in the base sequence of DNA alters the amino acid sequence and the protein and therefore it can have various effects
• What does the genetic code contain?

  start and stop codons
• is DNA in prokaryotic and eukaryotic cells the same?


  no