1.1. Table 1 shows the amino acids coded for by each of the mRNA codons. It also shows the properties of some of the amino acids. 

Table 1

Key

+ Represents amino acids with a positive charged R group

- Represents amino acids with a negative charge R group

Use information from Table 1 to explain, using an example, why the DNA code is said to be degenerate. 

1.2. A scientist investigated the structure of an enzyme containing 647 amino acids. She looked at mutations that commonly occurred and their effects on the protein structure.The mutations were all single base substitutions. 

One of the changes she discovered was at position 389 where Asp was substituted for Glu. 

Use Table 1 to suggest the likely effect of this mutation on the protein structure. 

1.3. Table 2 shows the positions of three different single base substitutions.  

Table 2

The mutation at position 531 did not affect the enzymes structure but the mutation at position 109 did. Using your knowledge of protein structure and information from Table 2  to explain this. 

1.4. Use information from Table 1 to tick one box that shows which single base mutation below would result in the amino acid Leu being replaced with the amino acid Arg. 

Table 1