Consequence Of Altering Code

Question 1

What is a point mutation

Answer 1

-changing of a single nucleotide in mRNA sequence

Question 2

Effects of point mutation and describe

Answer 2

1 silent mutation - changed codon may still code same aas

2 missense mutation - changed codon codes a diff aas

3 nonsense mutation - changed codon becomes termination sequence and produces truncated protein

Question 3

Other mutations ( non-point mutation ) List

Answer 3

1 tri nucleotide repeat expansion
2 splice site mutation
3 frame shift mutation

Question 4

Describe tri nucleotide repeat expansion

Answer 4

• codon repeated in tandem will be amplified

- too many copies of codon exist and too many aas inserted in protein

Question 5

Describe Huntington disease

Answer 5

• codon CAG repeats will add too many glutamine in huntingtin protein
• 2• protein structure changes leading to accumulation of protein aggregates

Question 6

Fragile X syndrome describe

Answer 6

• intellectual disease
• codon repeat expansion in UTR and decrease in protein made
• also leads to myotonic dystrophy

Question 7

Describe splice site mutations

Answer 7

• affects ways in which Introns are removed and they can be added to Exons or Exons removed
• change sequence and diff protein coded

Question 8

Describe frame shift mutations

Answer 8

• when 1/2 nucleotides are removed or Added from mRNA sequence
• alters reading frame ( sequence now mutated and read differently )

Question 9

How does frame shift mutation lead to truncated proteins

Answer 9

-leads to truncated protein is termination sequence added

Question 10

Effect of adding or removing a codon

Answer 10

• aas added

- aas lost

Question 11

Effect of reading frame by removing codon

Answer 11

-reading frame is maintained but aas lost

Question 12

Describe what type of disease cystic fibrosis is ,what it affects and ,how it’s comes about

Answer 12

• hereditary disease affecting pulmonary and digestive system
• loss of codon in gene
• loss of phenylalanine at 508th position ( DF508 ) of protein
• prevents normal folding of Protein CF transmembrane regulator ( CFTR )
• protein ubiquitinated
• production of thick sticky secretions in lungs and pancreas
• lung damage and digestive deficiencies

Question 13

Function of CFTR

Answer 13

-chloride channel in epithelium cells