Mutations

Question 1

What happens if a base is substituted?

Answer 1

• may have no effect due to degeneracy of the genetic code.
• sometimes one amino acid is changed but this doesn’t always change the protein.

Question 2

What happens if you insert or delete a base?

Answer 2

• A frameshift is caused.
• Every triplet downstream from the mutation is changed.
• Often a STOP codon is introduced, leading to the production of a shorter amino acid sequence.
• Making the protein non functional.

Question 3

How could a mutation produce ……….. ?

Answer 3

1. A change in the DNA base sequence occurs in the …. gene.
2. When the gene is transcribed, one or more codons in the mRNA are changed.
3. When the mRNA is translated, the …. protein contains a different sequence of amino acids.
4. The change in the primary structure means that there is a different sequence of R-groups.
5. This changes the bonding between R- groups.
6. This changes how the protein folds.
7. This changes the tertiary structure of the …… protein.
8. This means that the …… protein is non functional.
9. use info from question to answer…….

Question 4

What is the most common mutation that causes CF?

Answer 4

(triangle)F508-CFTR

deletion of 3 bases so doesn’t fold normally.

Question 5

how long is the CFTR gene?

Answer 5

230,000 base pairs