2.7 Genetic code

Question 1

How is the genetic code a triplet code?

Answer 1

• GC is made of a 3 letter base code
• Each triplet of bases forms one amino acid
• Some triplet codes code for stop or start signals
• Stop/start signals tell the cell where to start and stop reading to produce the correct amino acid

Question 2

How is the genetic code non-overlapping?

Answer 2

• Each base is only read once
• The same letter is not used for 2 different codons
• Adjacent codons do not overlap

Question 3

How is the genetic code degenerate?

Answer 3

• Multiple triplet codons will code for the same amino acid
• This limits the effect of mutations

Because the mutation may affect one set of codons but not all of them

Question 4

What is the definition of a gene?

Answer 4

A sequence of nucleotides that codes for a sequence of amino acids in a polypeptide chain
Genes control protein structure as they determine where amino acids join